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  • richardmitnick 9:24 pm on July 31, 2021 Permalink | Reply
    Tags: "Geologists take Earth’s inner temperature using erupted sea glass", , , Geologists at MIT have analyzed thousands of samples of erupted material along ocean ridges and traced back their chemical history to estimate the temperature of the Earth’s interior., , , , , , Plate Tectonics   

    From Massachusetts Institute of Technology (US) : “Geologists take Earth’s inner temperature using erupted sea glass” 

    MIT News

    From Massachusetts Institute of Technology (US)

    July 29, 2021
    Jennifer Chu

    1
    A map of the World Ocean Floor
    Credits: Library of Congress, Geography and Map Division.

    If the Earth’s oceans were drained completely, they would reveal a massive chain of undersea volcanoes snaking around the planet. This sprawling ocean ridge system is a product of overturning material in the Earth’s interior, where boiling temperatures can melt and loft rocks up through the crust, splitting the sea floor and reshaping the planet’s surface over hundreds of millions of years.

    Now geologists at MIT have analyzed thousands of samples of erupted material along ocean ridges and traced back their chemical history to estimate the temperature of the Earth’s interior.

    Their analysis shows that the temperature of the Earth’s underlying ocean ridges is relatively consistent, at around 1,350 degrees Celsius — about as hot as a gas range’s blue flame. There are, however, “hotspots” along the ridge that can reach 1,600 degrees Celsius, comparable to the hottest lava.

    The team’s results, appearing in the Journal of Geophysical Research:Solid Earth, provide a temperature map of the Earth’s interior around ocean ridges. With this map, scientists can better understand the melting processes that give rise to undersea volcanoes, and how these processes may drive the pace of plate tectonics over time.

    “Convection and plate tectonics have been important processes in shaping Earth history,” says lead author Stephanie Brown Krein, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “Knowing the temperature along this whole chain is fundamental to understanding the planet as a heat engine, and how Earth might be different from other planets and able to sustain life.”

    Krein’s co-authors include Zachary Molitor, an EAPS graduate student, and Timothy Grove, the R.R. Schrock Professor of Geology at MIT.

    A chemical history

    The Earth’s interior temperature has played a critical role in shaping the planet’s surface over hundreds of millions of years. But there’s been no way to directly read this temperature tens to hundreds of kilometers below the surface. Scientists have applied indirect means to infer the temperature of the upper mantle — the layer of the Earth just below the crust. But estimates thus far are inconclusive, and scientists disagree about how widely temperatures vary beneath the surface.

    For their new study, Krein and her colleagues developed a new algorithm, called “ReversePetrogen”, that is designed to trace a rock’s chemical history back in time, to identify its original composition of elements and determine the temperature at which the rock initially melted below the surface.

    The algorithm is based on years of experiments carried out in Grove’s lab to reproduce and characterize the melting processes of the Earth’s interior. Researchers in the lab have heated up rocks of various compositions, reaching various temperatures and pressures, to observe their chemical evolution. From these experiments, the team has been able to derive equations — and ultimately, the new algorithm — to predict the relationships between a rock’s temperature, pressure, and chemical composition.

    Krein and her colleagues applied their new algorithm to rocks collected along the Earth’s ocean ridges — a system of undersea volcanoes spanning more than 70,000 kilometers in length. Ocean ridges are regions where tectonic plates are spread apart by the eruption of material from the Earth’s mantle — a process that is driven by underlying temperatures.

    “You could effectively make a model of the temperature of the entire interior of the Earth, based partly on the temperature at these ridges,” Krein says. “The question is, what is the data really telling us about the temperature variation in the mantle along the whole chain?”

    Mantle map

    The data the team analyzed include more than 13,500 samples collected along the length of the ocean ridge system over several decades, by multiple research cruises. Each sample in the dataset is of an erupted sea glass — lava that erupted in the ocean and was instantly chilled by the surrounding water into a pristine, preserved form.

    Scientists previously identified the chemical compositions of each glass in the dataset. Krein and her colleagues ran each sample’s chemical compositions through their algorithm to determine the temperature at which each glass originally melted in the mantle.

    In this way, the team was able to generate a map of mantle temperatures along the entire length of the ocean ridge system. From this map, they observed that much of the mantle is relatively homogenous, with an average temperature of around 1,350 degrees Celsius. There are however, “hotspots,” or regions along the ridge, where temperatures in the mantle appear significantly hotter, at around 1,600 degrees Celsius.

    “People think of hotspots as regions in the mantle where it’s hotter, and where material may be melting more, and potentially rising faster, and we don’t exactly know why, or how much hotter they are, or what the role of composition is at hotspots,” Krein says. “Some of these hotspots are on the ridge, and now we may get a sense of what the hotspot variation is globally using this new technique. That tells us something fundamental about the temperature of the Earth now, and now we can think of how it’s changed over time.”

    Krein adds: “Understanding these dynamics will help us better determine how continents grew and evolved on Earth, and when subduction and plate tectonics started — which are critical for complex life.”

    This research was supported, in part, by the National Science Foundation(US).

    See the full article here .


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    Please help promote STEM in your local schools.

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    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    Massachusetts Institute of Technology (US) is a private land-grant research university in Cambridge, Massachusetts. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River. The institute also encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory (US), the MIT Bates Research and Engineering Center (US), and the Haystack Observatory (US), as well as affiliated laboratories such as the Broad Institute of MIT and Harvard(US) and Whitehead Institute (US).

    Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology (US) adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.

    As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with Massachusetts Institute of Technology (US) . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology (US) is a member of the Association of American Universities (AAU).

    Foundation and vision

    In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.

    Rogers, a professor from the University of Virginia (US), wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:

    “The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”

    The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.

    Early developments

    Two days after Massachusetts Institute of Technology (US) was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst (US)). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.

    Massachusetts Institute of Technology (US) was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.

    The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology (US) faculty and alumni rebuffed Harvard University (US) president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.

    In 1916, the Massachusetts Institute of Technology (US) administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.

    Curricular reforms

    In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology (US) catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities (US)in 1934.

    Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at Massachusetts Institute of Technology (US) that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.

    Massachusetts Institute of Technology (US)‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology (US)’s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, Massachusetts Institute of Technology (US) became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.

    These activities affected Massachusetts Institute of Technology (US) profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of Massachusetts Institute of Technology (US) between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, Massachusetts Institute of Technology (US) no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.

    In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and Massachusetts Institute of Technology (US)’s defense research. In this period Massachusetts Institute of Technology (US)’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. Massachusetts Institute of Technology (US) ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT (US) Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology (US) students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)

    In the 1980s, there was more controversy at Massachusetts Institute of Technology (US) over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, Massachusetts Institute of Technology (US)’s research for the military has included work on robots, drones and ‘battle suits’.

    Recent history

    Massachusetts Institute of Technology (US) has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology (US) classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.

    Massachusetts Institute of Technology (US) was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.

    In 2001, inspired by the open source and open access movements, Massachusetts Institute of Technology (US) launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, Massachusetts Institute of Technology (US) announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology (US) faculty adopted an open-access policy to make its scholarship publicly accessible online.

    Massachusetts Institute of Technology (US) has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology (US) community with thousands of police officers from the New England region and Canada. On November 25, 2013, Massachusetts Institute of Technology (US) announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of the Massachusetts Institute of Technology (US) community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.

    In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.

    The Caltech/MIT Advanced aLIGO (US) was designed and constructed by a team of scientists from California Institute of Technology (US), Massachusetts Institute of Technology (US), and industrial contractors, and funded by the National Science Foundation (US) .

    MIT/Caltech Advanced aLigo .

    It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology (US) physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also an Massachusetts Institute of Technology (US) graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.

    The mission of Massachusetts Institute of Technology (US) is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the Massachusetts Institute of Technology (US) community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

     
  • richardmitnick 1:56 pm on July 16, 2021 Permalink | Reply
    Tags: , Another material in the sediments is cosmogenic dust from outer space-tiny micrometeorites that bombard the Earth each day., , Dust is not only found on land though that is where it is most familiar to us. The pesky particles that build up on coffee tables also infiltrate our oceans., , Knowing how nutrient content levels have changed over millions of years can tell us more about how different plankton communities involved in the biological carbon pump have evolved ., , , Plankton use iron and other nutrients from the tiny specks to grow., Plate Tectonics, Recent research suggests that vents could be an important source of iron., , The scientists had to trek 10000 nautical miles through the South Pacific to a location near the Point Nemo region-the furthest point in the global ocean from land., There are no near-shore areas that will give you 100 million years of climate history so scientists need to go extreme locations to drill for sediments of that age.,   

    From Woods Hole Oceanographic Institution (US) : “Secrets in the Dust” 

    From Woods Hole Oceanographic Institution (US)

    September 24, 2020 [Re-presented 7.15.21]
    Evan Lubofsky

    1
    Credit: Natalie Renier © Woods Hole Oceanographic Institution.

    In the spring of 2010, a satellite the size of a small school bus plunged through the upper atmosphere like a fiery cannonball as it fell to the South Pacific Ocean, hair-raisingly close to where scientists aboard the research vessel (R/V) JOIDES Resolution happened to be working.

    “We got an alert from the European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) that it was bringing a satellite back down, basically telling us that we had to move within the next 24 hours,” says WHOI deputy director Rick Murray, who was there.

    The ship moved to a new location and avoided a catastrophic, albeit unlikely, collision with spacecraft. But, Murray says, the incident was “a stark reminder of how far away we actually were from everything else on this planet.”

    The researchers were in that desolate stretch of ocean— an area so removed from humanity that it’s become a cemetery for dying spacecraft—to learn about earlier episodes of climate change that can help inform future changes. Specifically, they were coring for ocean sediments, which contain various amounts of dust. “We can use the dust,” Murray says, “to tease out information about how climate changed in the Southern Hemisphere over millions of years.”

    A dusty ocean

    Dust is not only found on land though that is where it is most familiar to us. The pesky particles that build up on coffee tables also infiltrate our oceans, thanks to winds that constantly sweep it off land into the atmosphere. And that’s good, since plankton use iron and other nutrients from the tiny specks to grow. In the process, they draw down heat-trapping carbon dioxide (CO2) from the atmosphere above. When plankton eventually die and sink, some of them become buried in the seafloor. The carbon they’ve captured is buried along with them. As a result, dust has a direct and important impact on climate.

    Scientists at WHOI are investigating the amount of dust blown into the Southern Ocean over tens of millions of years. In doing so, they hope to pinpoint when the Earth went through periods of warm, slightly moister weather, and when the planet turned cooler and drier.

    Ann Dunlea, a marine geochemist at WHOI and one of Murray’s former graduate students when they were at Boston University (US), has been analyzing sediment samples from the 2010 R/V JOIDES Resolution expedition. She says looking at dust fluxes in the ocean over time enables her to understand the climatic history of the Southern Hemisphere and know, for example, at what point Australia became a dry and dusty place. It happened after the land mass dislodged from Antarctica 50-35 million years ago and migrated north, she says.

    3
    WHOI marine geochemist Ann Dunlea samples sediment from a core drilled on the R/V JOIDES Resolution. Analysis of dust in the samples allows her to reconstruct the climatic history of the Southern Hemisphere over tens of millions of years. Photo by Alex Reis.

    “In my data, you can see when the continent became desert-like as it tectonically migrated to 30 degrees south latitude,” Dunlea says. She can tell by the amount of dust that came off and drifted into the open ocean.

    Dust quantities are helping her reconstruct the region’s climactic history, which can inform predictions of future climate. But Dunlea is also analyzing the “oozy clay goo” to understand more about how iron and other micronutrients have cycled across ocean basins and influenced biological productivity in this oceanic desert, where nutrients run scarce. “Knowing how nutrient content levels have changed over millions of years can tell us more about how different plankton communities involved in the biological carbon pump have evolved over these time scales,” she says.

    A place of extremes

    None of these analyses would be possible without ancient ocean sediments, those that go way back to when dinosaurs walked the Earth.

    To collect sediments of that vintage, Murray and his colleagues had to trek 10,000 nautical miles through the South Pacific to a location near the Point Nemo region-the furthest point in the global ocean from land. “The sediment there is unique in that it accumulates incredibly slowly—about a meter per million years,” Murray says. “This means that there is a lot of time for the sediments to collect dust and minerals that we can use for analysis.”

    He says there are no near-shore areas that will give you 100 million years of climate history so scientists need to go extreme locations to drill for sediments of that age.

    “We were so far from anything, we would have been in a lot of trouble if something went wrong during the cruise. Like a satellite crashing down on us,” he laughs.

    Dust isn’t the only thing that persists in these ancient sediments. They also contain dormant deep-sea microbes that researchers from the JAPAN AGENCY FOR MARINE-EARTH SCIENCE AND TECHNOLOGY [国立研究開発法人海洋研究開発機構] (JP) (JAMSTEC) recently incubated, fed, and woke from their 100-million-year snooze fests.

    Another extreme, Murray says, was the tap-water-like clarity of the seawater where they drilled. “At one point we looked over the side of the ship and saw what appeared to be five-inch fish swimming deep down. When they came up to the surface, we couldn’t believe these tiny fish were actually 18-foot sharks!”

    4
    Due to incredibly clear waters, 18-foot sharks like the white-tipped shark shown here, looked like small fish down deep from the side of the ship during the 2010 R/V JOIDES Resolution expedition. Photo by Carlos Alvarez Zarikian, International Ocean Discovery Program, Texas A&M University (US))

    Understanding the sources

    Dunlea has found a window into ancient climate patterns, but the process hasn’t been without challenges. For instance, she has had to develop analytical techniques to distinguish continental dust from volcanic ash, which look identical even under a microscope. She must analyze the chemical composition of the sediments and ferret out hidden trends in the data with advanced statistical techniques.

    “It’s important to know what’s dust and what’s ash, since ash won’t tell us anything about warm or cold periods in the geologic record, and factoring it in will skew our results,” Dunlea says. “The ash can tell us, however, more about the history of volcanism, how many eruptions there have been, and how that may have impacted global climate.”

    Another material she has found in the sediments is cosmogenic dust from outer space-tiny micrometeorites that bombard the Earth each day. Dunlea says the slowly-accumulating sediment in the South Pacific Gyre also allows for a high concentration of these cosmic particles, some of which she can extract with a magnet.

    The next phase of the research will involve investigating how much iron content in the ocean may be coming from another source: metal-rich fluids erupting from hydrothermal vents on the seafloor.

    “It is commonly assumed that almost all iron in surface waters comes from dust, but recent research suggests that vents could be another important source of iron,” Dunlea says. “It’s unclear how far hydrothermal plumes can travel or if iron from them can reach surface waters, so those are some of the questions we’re trying to tackle in order to better understand past climate patterns and improve our predictions of future ones.”

    This research is funded by the National Science Foundation’s Division of Ocean Sciences (US).

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Woods Hole Oceanographic Institute

    Mission Statement

    The Woods Hole Oceanographic Institution (US) is dedicated to advancing knowledge of the ocean and its connection with the Earth system through a sustained commitment to excellence in science, engineering, and education, and to the application of this knowledge to problems facing society.

    Vision & Mission

    The ocean is a defining feature of our planet and crucial to life on Earth, yet it remains one of the planet’s last unexplored frontiers. For this reason, WHOI scientists and engineers are committed to understanding all facets of the ocean as well as its complex connections with Earth’s atmosphere, land, ice, seafloor, and life—including humanity. This is essential not only to advance knowledge about our planet, but also to ensure society’s long-term welfare and to help guide human stewardship of the environment. WHOI researchers are also dedicated to training future generations of ocean science leaders, to providing unbiased information that informs public policy and decision-making, and to expanding public awareness about the importance of the global ocean and its resources.

    The Institution is organized into six departments, the Cooperative Institute for Climate and Ocean Research, and a marine policy center. Its shore-based facilities are located in the village of Woods Hole, Massachusetts(US) and a mile and a half away on the Quissett Campus. The bulk of the Institution’s funding comes from grants and contracts from the National Science Foundation(US) and other government agencies, augmented by foundations and private donations.

    WHOI scientists, engineers, and students collaborate to develop theories, test ideas, build seagoing instruments, and collect data in diverse marine environments. Ships operated by WHOI carry research scientists throughout the world’s oceans. The WHOI fleet includes two large research vessels (R/V Atlantis and R/V Neil Armstrong); the coastal craft Tioga; small research craft such as the dive-operation work boat Echo; the deep-diving human-occupied submersible Alvin; the tethered, remotely operated vehicle Jason/Medea; and autonomous underwater vehicles such as the REMUS and SeaBED.
    WHOI offers graduate and post-doctoral studies in marine science. There are several fellowship and training programs, and graduate degrees are awarded through a joint program with the Massachusetts Institute of Technology(US). WHOI is accredited by the New England Association of Schools and Colleges (US). WHOI also offers public outreach programs and informal education through its Exhibit Center and summer tours. The Institution has a volunteer program and a membership program, WHOI Associate.

    On October 1, 2020, Peter B. de Menocal became the institution’s eleventh president and director.

    History

    In 1927, a National Academy of Sciences(US) committee concluded that it was time to “consider the share of the United States of America in a worldwide program of oceanographic research.” The committee’s recommendation for establishing a permanent independent research laboratory on the East Coast to “prosecute oceanography in all its branches” led to the founding in 1930 of the Woods Hole Oceanographic Institution(US).

    A $2.5 million grant from the Rockefeller Foundation supported the summer work of a dozen scientists, construction of a laboratory building and commissioning of a research vessel, the 142-foot (43 m) ketch R/V Atlantis, whose profile still forms the Institution’s logo.

    WHOI grew substantially to support significant defense-related research during World War II, and later began a steady growth in staff, research fleet, and scientific stature. From 1950 to 1956, the director was Dr. Edward “Iceberg” Smith, an Arctic explorer, oceanographer and retired Coast Guard rear admiral.

    In 1977 the institution appointed the influential oceanographer John Steele as director, and he served until his retirement in 1989.

    On 1 September 1985, a joint French-American expedition led by Jean-Louis Michel of IFREMER and Robert Ballard of the Woods Hole Oceanographic Institution identified the location of the wreck of the RMS Titanic which sank off the coast of Newfoundland 15 April 1912.

    On 3 April 2011, within a week of resuming of the search operation for Air France Flight 447, a team led by WHOI, operating full ocean depth autonomous underwater vehicles (AUVs) owned by the Waitt Institute discovered, by means of sidescan sonar, a large portion of debris field from flight AF447.

    In March 2017 the institution effected an open-access policy to make its research publicly accessible online.

    The Institution has maintained a long and controversial business collaboration with the treasure hunter company Odyssey Marine. Likewise, WHOI has participated in the location of the San José galleon in Colombia for the commercial exploitation of the shipwreck by the Government of President Santos and a private company.

    In 2019, iDefense reported that China’s hackers had launched cyberattacks on dozens of academic institutions in an attempt to gain information on technology being developed for the United States Navy. Some of the targets included the Woods Hole Oceanographic Institution. The attacks have been underway since at least April 2017.

     
  • richardmitnick 9:29 am on June 12, 2021 Permalink | Reply
    Tags: "A Tectonic Shift in Analytics and Computing Is Coming", "Destination Earth", "Speech Understanding Research", "tensor processing units", , , , Computing clusters, , GANs: generative adversarial networks, , , Plate Tectonics, , Seafloor bathymetry, SML: supervised machine learning, UML: Unsupervised Machine Learning   

    From Eos: “A Tectonic Shift in Analytics and Computing Is Coming” 

    From AGU
    Eos news bloc

    From Eos

    4 June 2021
    Gabriele Morra
    morra@louisiana.edu
    Ebru Bozdag
    Matt Knepley
    Ludovic Räss
    Velimir Vesselinov

    Artificial intelligence combined with high-performance computing could trigger a fundamental change in how geoscientists extract knowledge from large volumes of data.

    1
    A Cartesian representation of a global adjoint tomography model, which uses high-performance computing capabilities to simulate seismic wave propagation, is shown here. Blue and red colorations represent regions of high and low seismic velocities, respectively. Credit: David Pugmire, DOE’s Oak Ridge National Laboratory (US).

    More than 50 years ago, a fundamental scientific revolution occurred, sparked by the concurrent emergence of a huge amount of new data on seafloor bathymetry and profound intellectual insights from researchers rethinking conventional wisdom. Data and insight combined to produce the paradigm of plate tectonics. Similarly, in the coming decade, a new revolution in data analytics may rapidly overhaul how we derive knowledge from data in the geosciences. Two interrelated elements will be central in this process: artificial intelligence (AI, including machine learning methods as a subset) and high-performance computing (HPC).

    Already today, geoscientists must understand modern tools of data analytics and the hardware on which they work. Now AI and HPC, along with cloud computing and interactive programming languages, are becoming essential tools for geoscientists. Here we discuss the current state of AI and HPC in Earth science and anticipate future trends that will shape applications of these developing technologies in the field. We also propose that it is time to rethink graduate and professional education to account for and capitalize on these quickly emerging tools.

    Work in Progress

    Great strides in AI capabilities, including speech and facial recognition, have been made over the past decade, but the origins of these capabilities date back much further. In 1971, the Defense Advanced Research Projects Agency (US) substantially funded a project called Speech Understanding Research [Journal of the Acoustical Society of America], and it was generally believed at the time that artificial speech recognition was just around the corner. We know now that this was not the case, as today’s speech and writing recognition capabilities emerged only as a result of both vastly increased computing power and conceptual breakthroughs such as the use of multilayered neural networks, which mimic the biological structure of the brain.

    Recently, AI has gained the ability to create images of artificial faces that humans cannot distinguish from real ones by using generative adversarial networks (GANs). These networks combine two neural networks, one that produces a model and a second one that tries to discriminate the generated model from the real one. Scientists have now started to use GANs to generate artificial geoscientific data sets.

    These and other advances are striking, yet AI and many other artificial computing tools are still in their infancy. We cannot predict what AI will be able to do 20–30 years from now, but a survey of existing AI applications recently showed that computing power is the key when targeting practical applications today. The fact that AI is still in its early stages has important implications for HPC in the geosciences. Currently, geoscientific HPC studies have been dominated by large-scale time-dependent numerical simulations that use physical observations to generate models [Morra et al, 2021a*]. In the future, however, we may work in the other direction—Earth, ocean, and atmospheric simulations may feed large AI systems that in turn produce artificial data sets that allow geoscientific investigations, such as Destination Earth, for which collected data are insufficient.

    *all citations are included in References below.

    Data-Centric Geosciences

    Development of AI capabilities is well underway in certain geoscience disciplines. For a decade now [Ma et al., 2019], remote sensing operations have been using convolutional neural networks (CNNs), a kind of neural network that adaptively learns which features to look at in a data set. In seismology (Figure 1), pattern recognition is the most common application of machine learning (ML), and recently, CNNs have been trained to find patterns in seismic data [Kong et al., 2019], leading to discoveries such as previously unrecognized seismic events [Bergen et al., 2019].

    2
    Fig. 1. Example of a workflow used to produce an interactive “visulation” system, in which graphic visualization and computer simulation occur simultaneously, for analysis of seismic data. Credit: Ben Kadlec.

    New AI applications and technologies are also emerging; these involve, for example, the self-ordering of seismic waveforms to detect structural anomalies in the deep mantle [Kim et al., 2020]. Recently, deep generative models, which are based on neural networks, have shown impressive capabilities in modeling complex natural signals, with the most promising applications in autoencoders and GANs (e.g., for generating images from data).

    CNNs are a form of supervised machine learning (SML), meaning that before they are applied for their intended use, they are first trained to find prespecified patterns in labeled data sets and to check their accuracy against an answer key. Training a neural network using SML requires large, well-labeled data sets as well as massive computing power. Massive computing power, in turn, requires massive amounts of electricity, such that the energy demand of modern AI models is doubling every 3.4 months and causing a large and growing carbon footprint.

    In the future, the trend in geoscientific applications of AI might shift from using bigger CNNs to using more scalable algorithms that can improve performance with less training data and fewer computing resources. Alternative strategies will likely involve less energy-intensive neural networks, such as spiking neural networks, which reduce data inputs by analyzing discrete events rather than continuous data streams.

    Unsupervised ML (UML), in which an algorithm identifies patterns on its own rather than searching for a user-specified pattern, is another alternative to data-hungry SML. One type of UML identifies unique features in a data set to allow users to discover anomalies of interest (e.g., evidence of hidden geothermal resources in seismic data) and to distinguish trends of interest (e.g., rapidly versus slowly declining production from oil and gas wells based on production rate transients) [Vesselinov et al., 2019].

    AI is also starting to improve the efficiency of geophysical sensors. Data storage limitations require instruments such as seismic stations, acoustic sensors, infrared cameras, and remote sensors to record and save data sets that are much smaller than the total amount of data they measure. Some sensors use AI to detect when “interesting” data are recorded, and these data are selectively stored. Sensor-based AI algorithms also help minimize energy consumption by and prolong the life of sensors located in remote regions, which are difficult to service and often powered by a single solar panel. These techniques include quantized CNN (using 8-bit variables) running on minimal hardware, such as Raspberry Pi [Wilkes et al., 2017].

    Advances in Computing Architectures

    Powerful, efficient algorithms and software represent only one part of the data revolution; the hardware and networks that we use to process and store data have evolved significantly as well.

    Since about 2004, when the increase in frequencies at which processors operate stalled at about 3 gigahertz (the end of Moore’s law), computing power has been augmented by increasing the number of cores per CPU and by the parallel work of cores in multiple CPUs, as in computing clusters.

    Accelerators such as graphics processing units (GPUs), once used mostly for video games, are now routinely used for AI applications and are at the heart of all major ML facilities (as well the DOE’s Exascale Ccomputing Project (US), a part of the National Strategic Computing Initiative – NSF (US)). For example, Summit and Sierra, the two fastest supercomputers in the United States, are based on a hierarchical CPU-GPU architecture.

    Meanwhile, emerging tensor processing units, which were developed specifically for matrix-based operations, excel at the most demanding tasks of most neural network algorithms. In the future, computers will likely become increasingly heterogeneous, with a single system combining several types of processors, including specialized ML coprocessors (e.g., Cerebras) and quantum computing processors.

    Computational systems that are physically distributed across remote locations and used on demand, usually called cloud computing, are also becoming more common, although these systems impose limitations on the code that can be run on them. For example, cloud infrastructures, in contrast to centralized HPC clusters and supercomputers, are not designed for performing large-scale parallel simulations. Cloud infrastructures face limitations on high-throughput interconnectivity, and the synchronization needed to help multiple computing nodes coordinate tasks is substantially more difficult to achieve for physically remote clusters. Although several cloud-based computing providers are now investing in high-throughput interconnectivity, the problem of synchronization will likely remain for the foreseeable future.

    Boosting 3D Simulations

    Artificial intelligence has proven invaluable in discovering and analyzing patterns in large, real-world data sets. It could also become a source of realistic artificial data sets, generated through models and simulations. Artificial data sets enable geophysicists to examine problems that are unwieldy or intractable using real-world data—because these data may be too costly or technically demanding to obtain—and to explore what-if scenarios or interconnected physical phenomena in isolation. For example, simulations could generate artificial data to help study seismic wave propagation; large-scale geodynamics; or flows of water, oil, and carbon dioxide through rock formations to assist in energy extraction and storage.

    HPC and cloud computing will help produce and run 3D models, not only assisting in improved visualization of natural processes but also allowing for investigation of processes that can’t be adequately studied with 2D modeling. In geodynamics, for example, using 2D modeling makes it difficult to calculate 3D phenomena like toroidal flow and vorticity because flow patterns are radically different in 3D. Meanwhile, phenomena like crustal porosity waves [Geophysical Research Letters] (waves of high porosity in rocks; Figure 2) and corridors of fast-moving ice in glaciers require extremely high spatial and temporal resolutions in 3D to capture [Räss et al., 2020].

    3
    Fig. 2. A 3D modeling run with 16 billion degrees of freedom simulates flow focusing in porous media and identifies a pulsed behavior phenomenon called porosity waves. Credit: Räss et al. [2018], CC BY 4.0.

    Adding an additional dimension to a model can require a significant increase in the amount of data processed. For example, in exploration seismology, going from a 2D to a 3D simulation involves a transition from requiring three-dimensional data (i.e., source, receiver, time) to five-dimensional data (source x, source y, receiver x, receiver y, and time [e.g., Witte et al., 2020]). AI can help with this transition. At the global scale, for example, the assimilation of 3D simulations in iterative full-waveform inversions for seismic imaging was performed recently with limited real-world data sets, employing AI techniques to maximize the amount of information extracted from seismic traces while maintaining the high quality of the data [Lei et al., 2020].

    Emerging Methods and Enhancing Education

    As far as we’ve come in developing AI for uses in geoscientific research, there is plenty of room for growth in the algorithms and computing infrastructure already mentioned, as well as in other developing technologies. For example, interactive programming, in which the programmer develops new code while a program is active, and language-agnostic programming environments that can run code in a variety of languages are young techniques that will facilitate introducing computing to geoscientists.

    Programming languages, such as Python and Julia, which are now being taught to Earth science students, will accompany the transition to these new methods and will be used in interactive environments such as the Jupyter Notebook. Julia was shown recently to perform well as compiled code for machine learning algorithms in its most recent implementations, such as the ones using differentiable programming, which reduces computational resource and energy requirements.

    Quantum computing, which uses the quantum states of atoms rather than streams of electrons to transmit data, is another promising development that is still in its infancy but that may lead to the next major scientific revolution. It is forecast that by the end of this decade, quantum computers will be applied in solving many scientific problems, including those related to wave propagation, crustal stresses, atmospheric simulations, and other topics in the geosciences. With competition from China in developing quantum technologies and AI, quantum computing and quantum information applications may become darlings of major funding opportunities, offering the means for ambitious geophysicists to pursue fundamental research.

    Taking advantage of these new capabilities will, of course, require geoscientists who know how to use them. Today, many geoscientists face enormous pressure to requalify themselves for a rapidly changing job market and to keep pace with the growing complexity of computational technologies. Academia, meanwhile, faces the demanding task of designing innovative training to help students and others adapt to market conditions, although finding professionals who can teach these courses is challenging because they are in high demand in the private sector. However, such teaching opportunities could provide a point of entry for young scientists specializing in computer science or part-time positions for professionals retired from industry or national labs [Morra et al., 2021b].

    The coming decade will see a rapid revolution in data analytics that will significantly affect the processing and flow of information in the geosciences. Artificial intelligence and high-performance computing are the two central elements shaping this new landscape. Students and professionals in the geosciences will need new forms of education enabling them to rapidly learn the modern tools of data analytics and predictive modeling. If done well, the concurrence of these new tools and a workforce primed to capitalize on them could lead to new paradigm-shifting insights that, much as the plate tectonic revolution did, help us address major geoscientific questions in the future.

    Acknowledgments:

    The listed authors thank Peter Gerstoft, Scripps Institution of Oceanography (US), University of California, San Diego; Henry M. Tufo, University of Colorado-Boulder (US); and David A. Yuen, Columbia University (US) and Ocean University of China [中國海洋大學](CN), Qingdao, who contributed equally to the writing of this article.

    References:

    Bergen, K. J., et al. (2019), Machine learning for data-driven discovery in solid Earth geoscience, Science, 363(6433), eaau0323, https://doi.org/10.1126/science.aau0323.

    Kim, D., et al. (2020), Sequencing seismograms: A panoptic view of scattering in the core-mantle boundary region, Science, 368(6496), 1,223–1,228, https://doi.org/10.1126/science.aba8972.

    Kong, Q., et al. (2019), Machine learning in seismology: Turning data into insights, Seismol. Res. Lett., 90(1), 3–14, https://doi.org/10.1785/0220180259.

    Lei, W., et al. (2020), Global adjoint tomography—Model GLAD-M25, Geophys. J. Int., 223(1), 1–21, https://doi.org/10.1093/gji/ggaa253.

    Ma, L., et al. (2019), Deep learning in remote sensing applications: A meta-analysis and review, ISPRS J. Photogramm. Remote Sens., 152, 166–177, https://doi.org/10.1016/j.isprsjprs.2019.04.015.

    Morra, G., et al. (2021a), Fresh outlook on numerical methods for geodynamics. Part 1: Introduction and modeling, in Encyclopedia of Geology, 2nd ed., edited by D. Alderton and S. A. Elias, pp. 826–840, Academic, Cambridge, Mass., https://doi.org/10.1016/B978-0-08-102908-4.00110-7.

    Morra, G., et al. (2021b), Fresh outlook on numerical methods for geodynamics. Part 2: Big data, HPC, education, in Encyclopedia of Geology, 2nd ed., edited by D. Alderton and S. A. Elias, pp. 841–855, Academic, Cambridge, Mass., https://doi.org/10.1016/B978-0-08-102908-4.00111-9.

    Räss, L., N. S. C. Simon, and Y. Y. Podladchikov (2018), Spontaneous formation of fluid escape pipes from subsurface reservoirs, Sci. Rep., 8, 11116, https://doi.org/10.1038/s41598-018-29485-5.

    Räss, L., et al. (2020), Modelling thermomechanical ice deformation using an implicit pseudo-transient method (FastICE v1.0) based on graphical processing units (GPUs), Geosci. Model Dev., 13, 955–976, https://doi.org/10.5194/gmd-13-955-2020.

    Vesselinov, V. V., et al. (2019), Unsupervised machine learning based on non-negative tensor factorization for analyzing reactive-mixing, J. Comput. Phys., 395, 85–104, https://doi.org/10.1016/j.jcp.2019.05.039.

    Wilkes, T. C., et al. (2017), A low-cost smartphone sensor-based UV camera for volcanic SO2 emission measurements, Remote Sens., 9(1), 27, https://doi.org/10.3390/rs9010027.

    Witte, P. A., et al. (2020), An event-driven approach to serverless seismic imaging in the cloud, IEEE Trans. Parallel Distrib. Syst., 31, 2,032–2,049, https://doi.org/10.1109/TPDS.2020.2982626.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 12:11 pm on June 3, 2021 Permalink | Reply
    Tags: "An Academic Role Model", As a Latina and a woman in the geosciences she said she has also experienced the challenges of entering a field as part of an underrepresented group., , Morell plans to apply the recognition and funding from her CAREER award to reach out to underrepresented students., Plate boundaries are able to generate the largest earthquakes., Plate Tectonics, , , Women in STEM-Kristin Morell   

    From University of California-Santa Barbara (US) : Women in STEM-Kristin Morell “An Academic Role Model” 

    UC Santa Barbara Name bloc

    From University of California-Santa Barbara (US)

    June 1, 2021
    Harrison Tasoff
    (805) 893-7220
    harrisontasoff@ucsb.edu

    1
    Kristin Morell. Credit: UC Santa Barbara.

    The National Science Foundation (US) has honored UC Santa Barbara Assistant Professor Kristin Morell as one of its 2021 Faculty Early Career Development (CAREER) award winners. The CAREER award is the foundation’s most prestigious honor in support of early career faculty, recognizing young faculty who have the potential to become exemplars in research and education.

    “I’m tremendously honored to have received this award, and I’m really looking forward to encouraging more students to become excited about the geosciences and enjoying fieldwork,” Morell said. She plans to leverage the distinction and funding to support her research on plate tectonics and provide opportunities for underrepresented students to get involved in geoscience.

    “The department could not be prouder that the National Science Foundation has given its most prestigious award for early career faculty to Professor Morell,” said Andy Wyss, chair of the earth science department. “This Himalayan-scale distinction widely announces a rising star in our discipline. It will springboard her to an even more influential position as a research and educational role model, and will help our department meet many of its most pressing goals. We look forward to the prominent leadership role Kristin will assume as she enters the next phase of her career.”

    Morell specializes in studying subduction zones, where one tectonic plate dives below another. Because of the amount of contact this provides between the two plates, these boundaries are able to generate the largest earthquakes.

    Our current understanding of subduction zones is that the plunging plate drags the overlying plate with it as it slips beneath. This builds up stress, which causes the rock to strain. An earthquake occurs when the plates finally slip, and both the motion of the lower plate and the springing of the upper plate contribute to the shacking that occurs during an earthquake.

    That said, scientists don’t know a lot about how the overlying plate rebounds during this process. The traditional model assumes most of the deformation in the rock is temporary, and that the rock returns to its initial shape once stress is released by an earthquake.

    The theory is simple and intuitive, but scientists have observed deformation in the upper plate that’s not accounted for in our current understanding. Field observations and recent quakes show that earthquakes can also occur within the overlying rock, and this rock may also not simply return to its initial shape and position afterward. Sorting out the mechanisms at work will advance knowledge of what is both a significant aspect of plate tectonics as well as something that affects earthquake preparedness.

    Morell loves what she studies, but as a Latina in the geosciences she said she has also experienced the challenges of entering a field as part of an underrepresented group. Wanting more people to have the opportunity to consider a career in earth science, she plans to apply the recognition and funding from her CAREER award to reach out to underrepresented students.

    2
    Morell teaches a field course to undergraduate students in British Columbia, Canada. Credit: DAVID NELLES.

    With part of the $600,009 funding that came with the award, Morell intends to create one-year research internships for four undergraduates to accompany her in the field on Kodiak Island, Alaska and the Nicoya Peninsula in Costa Rica. The internships will be coordinated through the Center for Science and Engineering Partnerships (CSEP), and provide two spots for UC Santa Barbara students and two spots for Santa Barbara Community College students. The funds will also enable Morell to expand her research by recruiting two graduate students to the earth science department.

    She’s also working with the campus group MAPAS (Making Adventures Accessible for All Students), which is designed to foster a comfort with the outdoors in students who may have reservations about outdoor activities. Morell plans to lead field trips to local spots, like Lizard’s Mouth, as well as longer trips to places like Yosemite and Joshua Tree National Parks.

    “Trepidation about the outdoors can be one of the largest barriers to students getting into the geosciences,” Morell explained. “The field component of our discipline can either be a plus or a minus for students. This initiative is designed to break down some of these barriers so that students can enjoy the excitement of being in the field instead of feeling left out or uncomfortable in the outdoors.”

    Morell also plans to lead smaller workshops, like one demystifying the backpacking experience. “Because we were limited to only having a small number of internships, I wanted a way to grab a larger audience of students to become interested in field work and in the geosciences in general,” she said.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    UC Santa Barbara Seal

    The University of California-Santa Barbara (US) is a public land-grant research university in Santa Barbara, California, and one of the ten campuses of the University of California(US) system. Tracing its roots back to 1891 as an independent teachers’ college, UCSB joined the University of California system in 1944, and is the third-oldest undergraduate campus in the system.

    The university is a comprehensive doctoral university and is organized into five colleges and schools offering 87 undergraduate degrees and 55 graduate degrees. It is classified among “R1: Doctoral Universities – Very high research activity”. According to the National Science Foundation(US), UC Santa Barbara spent $235 million on research and development in fiscal year 2018, ranking it 100th in the nation. In his 2001 book The Public Ivies: America’s Flagship Public Universities, author Howard Greene labeled UCSB a “Public Ivy”.

    UC Santa Barbara is a research university with 10 national research centers, including the Kavli Institute for Theoretical Physics (US) and the Center for Control, Dynamical-Systems and Computation. Current UCSB faculty includes six Nobel Prize laureates; one Fields Medalist; 39 members of the National Academy of Sciences (US); 27 members of the National Academy of Engineering (US); and 34 members of the American Academy of Arts and Sciences (US). UCSB was the No. 3 host on the ARPANET and was elected to the Association of American Universities in 1995. The faculty also includes two Academy and Emmy Award winners and recipients of a Millennium Technology Prize; an IEEE Medal of Honor; a National Medal of Technology and Innovation; and a Breakthrough Prize in Fundamental Physics.

    The UC Santa Barbara Gauchos compete in the Big West Conference of the NCAA Division I. The Gauchos have won NCAA national championships in men’s soccer and men’s water polo.

    History

    UCSB traces its origins back to the Anna Blake School, which was founded in 1891, and offered training in home economics and industrial arts. The Anna Blake School was taken over by the state in 1909 and became the Santa Barbara State Normal School which then became the Santa Barbara State College in 1921.

    In 1944, intense lobbying by an interest group in the City of Santa Barbara led by Thomas Storke and Pearl Chase persuaded the State Legislature, Gov. Earl Warren, and the Regents of the University of California to move the State College over to the more research-oriented University of California system. The State College system sued to stop the takeover but the governor did not support the suit. A state constitutional amendment was passed in 1946 to stop subsequent conversions of State Colleges to University of California campuses.

    From 1944 to 1958, the school was known as Santa Barbara College of the University of California, before taking on its current name. When the vacated Marine Corps training station in Goleta was purchased for the rapidly growing college Santa Barbara City College moved into the vacated State College buildings.

    Originally the regents envisioned a small several thousand–student liberal arts college a so-called “Williams College (US) of the West”, at Santa Barbara. Chronologically, UCSB is the third general-education campus of the University of California, after UC Berkeley (US) and UCLA (US) (the only other state campus to have been acquired by the UC system). The original campus the regents acquired in Santa Barbara was located on only 100 acres (40 ha) of largely unusable land on a seaside mesa. The availability of a 400-acre (160 ha) portion of the land used as Marine Corps Air Station Santa Barbara until 1946 on another seaside mesa in Goleta, which the regents could acquire for free from the federal government, led to that site becoming the Santa Barbara campus in 1949.

    Originally only 3000–3500 students were anticipated but the post-WWII baby boom led to the designation of general campus in 1958 along with a name change from “Santa Barbara College” to “University of California, Santa Barbara,” and the discontinuation of the industrial arts program for which the state college was famous. A chancellor- Samuel B. Gould- was appointed in 1959.

    In 1959 UCSB professor Douwe Stuurman hosted the English writer Aldous Huxley as the university’s first visiting professor. Huxley delivered a lectures series called The Human Situation.

    In the late ’60s and early ’70s UCSB became nationally known as a hotbed of anti–Vietnam War activity. A bombing at the school’s faculty club in 1969 killed the caretaker Dover Sharp. In the spring of 1970 multiple occasions of arson occurred including a burning of the Bank of America branch building in the student community of Isla Vista during which time one male student Kevin Moran was shot and killed by police. UCSB’s anti-Vietnam activity impelled then-Gov. Ronald Reagan to impose a curfew and order the National Guard to enforce it. Armed guardsmen were a common sight on campus and in Isla Vista during this time.

    In 1995 UCSB was elected to the Association of American Universities– an organization of leading research universities with a membership consisting of 59 universities in the United States (both public and private) and two universities in Canada.

    On May 23, 2014 a killing spree occurred in Isla Vista, California, a community in close proximity to the campus. All six people killed during the rampage were students at UCSB. The murderer was a former Santa Barbara City College student who lived in Isla Vista.

    Research activity

    According to the National Science Foundation (US), UC Santa Barbara spent $236.5 million on research and development in fiscal 2013, ranking it 87th in the nation.

    From 2005 to 2009 UCSB was ranked fourth in terms of relative citation impact in the U.S. (behind Massachusetts Institute of Technology (US), California Institute of Technology(US), and Princeton University (US)) according to Thomson Reuters.

    UCSB hosts 12 National Research Centers, including the Kavli Institute for Theoretical Physics, the National Center for Ecological Analysis and Synthesis, the Southern California Earthquake Center, the UCSB Center for Spatial Studies, an affiliate of the National Center for Geographic Information and Analysis, and the California Nanosystems Institute. Eight of these centers are supported by the National Science Foundation. UCSB is also home to Microsoft Station Q, a research group working on topological quantum computing where American mathematician and Fields Medalist Michael Freedman is the director.

    Research impact rankings

    The Times Higher Education World University Rankings ranked UCSB 48th worldwide for 2016–17, while the Academic Ranking of World Universities (ARWU) in 2016 ranked UCSB 42nd in the world; 28th in the nation; and in 2015 tied for 17th worldwide in engineering.

    In the United States National Research Council rankings of graduate programs, 10 UCSB departments were ranked in the top ten in the country: Materials; Chemical Engineering; Computer Science; Electrical and Computer Engineering; Mechanical Engineering; Physics; Marine Science Institute; Geography; History; and Theater and Dance. Among U.S. university Materials Science and Engineering programs, UCSB was ranked first in each measure of a study by the National Research Council of the NAS.

    The Centre for Science and Technologies Studies at

     
  • richardmitnick 2:01 pm on April 4, 2021 Permalink | Reply
    Tags: "Deep diamonds contain evidence of deep-Earth recycling processes", , , , , , Plate Tectonics, Serpentinite-a rock that forms from peridotite-the main rock type in Earth’s mantle can carry surface water as far as 700 kilometers deep by plate tectonic processes., Subduction-how the Earth recycles its materials.   

    From Carnegie Institution for Science (US) : “Deep diamonds contain evidence of deep-Earth recycling processes” 

    Carnegie Institution for Science

    From Carnegie Institution for Science (US)

    March 31, 2021

    Diamonds that formed deep in the Earth’s mantle contain evidence of chemical reactions that occurred on the seafloor. Probing these gems can help geoscientists understand how material is exchanged between the planet’s surface and its depths.

    Given that the bottom of the ocean is just 11 kilometers (6.8 miles) down at its deepest point, this may seem rather odd – but those diamonds are a really valuable clue for understanding the exchange of material between Earth’s surface and its crushing depths, researchers say.

    1
    An illustration showing how diamonds can offer researchers a glimpse into the processes occurring inside our planet, including deep-Earth recycling of surface material. Credit: Katherine Cain/Carnegie Institution for Science.

    2
    Examples of rough CLIPPIR diamonds from the Letseng mine, Lesotho. These are the same kinds of diamonds as the ones analyzed in this study. Largest stone is 91.07 carats. Credit: Robert Weldon; copyright GIA; courtesy of Gem Diamonds Ltd.

    New work published in Science Advances confirms that serpentinite—a rock that forms from peridotite, the main rock type in Earth’s mantle, when water penetrates cracks in the ocean floor—can carry surface water as far as 700 kilometers deep by plate tectonic processes.

    “Nearly all tectonic plates that make up the seafloor eventually bend and slide down into the mantle—a process called subduction, which has the potential to recycle surface materials, such as water, into the Earth,” explained Carnegie’s Peng Ni, who co-led the research effort with Evan Smith of the Gemological Institute of America.

    Diamonds are prized for their beauty when shaped into faceted gems, but the little clear lumps of carbon can tell us a lot about the conditions in which they formed. Not all diamonds are perfectly clear; some contain what we call inclusions, fragments of other minerals that got caught up in the diamond formation process (and, once, a whole other diamond).

    Sometimes, we can tell these inclusions are from the deep environment where the diamond formed; calcium silicate perovskite, for instance, is unstable at depths above about 650 kilometers except when it’s been trapped in a diamond, so it’s unlikely to have formed at the surface.

    Where commercial diamond companies see impurities, scientists see inclusions, and the team took this opportunity to study the planet’s interior. Instead of deep minerals, though, the researchers found heavy isotopes of iron, outside the known values for iron from those mantle depths, or the products of reactions we’d expect at those depths.

    This, they say, is the first evidence confirming a geochemical pathway to capture and transport surface materials deep into the mantle.

    Serpentinite residing inside subducting plates may be one of the most significant, yet poorly known, geochemical pathways by which surface materials are captured and conveyed into the Earth’s depths. The presence of deeply-subducted serpentinites was previously suspected—due to Carnegie and GIA research about the origin of blue diamonds and to the chemical composition of erupted mantle material that makes up mid-ocean ridges, seamounts, and ocean islands. But evidence demonstrating this pathway had not been fully confirmed until now.

    The research team—which also included Carnegie’s Steven Shirey, and Anat Shahar, as well as GIA’s Wuyi Wang and Stephen Richardson of the University of Cape Town (SA)—found physical evidence to confirm this suspicion by studying a type of large diamonds that originate deep inside the planet.

    “Some of the most famous diamonds in the world fall into this special category of relatively large and pure gem diamonds, such as the world-famous Cullinan,” Smith said. “They form between 360 and 750 kilometers down, at least as deep as the transition zone between the upper and lower mantle.”

    Sometimes they contain inclusions of tiny minerals trapped during diamond crystallization that provide a glimpse into what is happening at these extreme depths.

    3
    This cartoon shows a subducting oceanic plate traveling like a conveyor belt from the surface down to the lower mantle. The white arrows show the comparatively well-established shallow recycling pathway in the top layer of the plate (crust and sediments), that feeds into arc volcanoes. Our new findings from studying diamonds reveal a deeper recycling pathway, shown in light blue. Water infiltrating fractures in the seafloor hydrates the rocks in the interior of the plate (forming “serpentinite”), and these hydrated rocks can sometimes be carried down to the top of the lower mantle. This is a major pathway that transfers water, carbon, and other surficial elements deep down into the mantle. Credit: Wenjia Fan/ W. Design Studio.

    “Studying small samples of minerals formed during deep diamond crystallization can teach us so much about the composition and dynamics of the mantle, because diamond protects the minerals from additional changes on their path to the surface,” Shirey explained.

    In this instance, the researchers were able to analyze the isotopic composition of iron in the metallic inclusions. Like other elements, iron can have different numbers of neutrons in its nucleus, which gives rise to iron atoms of slightly different mass, or different “isotopes” of iron. Measuring the ratios of “heavy” and “light” iron isotopes gives scientists a sort of fingerprint of the iron.

    The diamond inclusions studied by the team had a higher ratio of heavy to light iron isotopes than typically found in most mantle minerals. This indicates that they probably didn’t originate from deep-Earth geochemical processes. Instead, it points to magnetite and other iron-rich minerals formed when oceanic plate peridotite transformed to serpentinite on the seafloor. This hydrated rock was eventually subducted hundreds of kilometers down into the mantle transition zone, where these particular diamonds crystallized.

    “Our findings confirm a long-suspected pathway for deep-Earth recycling, allowing us to trace how minerals from the surface are drawn down into the mantle and create variability in its composition,” Shahar concluded.

    __________________

    This work was supported by the Diamonds and Mantle Geodynamics Group of the Deep Carbon Observatory, a U.S. National Science Foundation grant, and the research program of the Gemological Institute of America.

    See the full article here .


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    Carnegie Institution of Washington Bldg

    Carnegie Institution for Science (US)

    Andrew Carnegie established a unique organization dedicated to scientific discovery “to encourage in the broadest and most liberal manner investigation; research; and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

    The Carnegie Institution of Washington (US) (the organization’s legal name), known also for public purposes as the Carnegie Institution for Science (US) (CIS), is an organization in the United States established to fund and perform scientific research. The institution is headquartered in Washington, D.C. As of June 30, 2020, the Institution’s endowment was valued at $926.9 million. In 2018 the expenses for scientific programs and administration were $96.6 million.

    History

    When the United States joined World War II Vannevar Bush was president of the Carnegie Institution. Several months before on June 12, 1940 Bush had been instrumental in persuading President Franklin Roosevelt to create the National Defense Research Committee (later superseded by the Office of Scientific Research and Development) to mobilize and coordinate the nation’s scientific war effort. Bush housed the new agency in the Carnegie Institution’s administrative headquarters at 16th and P Streets, NW, in Washington, DC, converting its rotunda and auditorium into office cubicles. From this location Bush supervised, among many other projects the Manhattan Project. Carnegie scientists cooperated with the development of the proximity fuze and mass production of penicillin.

    Research

    Carnegie scientists continue to be involved with scientific discovery. Composed of six scientific departments on the East and West Coasts the Carnegie Institution for Science is involved presently with six main topics: Astronomy at the Department of Terrestrial Magnetism (Washington, D.C.) and the Observatories of the Carnegie Institution of Washington (Pasadena, CA and Las Campanas, Chile); Earth and planetary science also at the Department of Terrestrial Magnetism and the Geophysical Laboratory (Washington, D.C.); Global Ecology at the Department of Global Ecology (Stanford, CA); Genetics and developmental biology at the Department of Embryology (Baltimore, MD); Matter at extreme states also at the Geophysical Laboratory; and Plant science at the Department of Plant Biology (Stanford, CA).

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high.


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile.

    Carnegie Institution 1-meter Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena, near the north end of a 7 km (4.3 mi) long mountain ridge, Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile.

     
  • richardmitnick 9:30 am on March 6, 2021 Permalink | Reply
    Tags: "Volcanoes might light up the night sky of this planet", , Exoplanet planet LHS 3844b, Plate Tectonics, ,   

    From University of Bern [Universität Bern](CH): “Volcanoes might light up the night sky of this planet” 

    From University of Bern [Universität Bern](CH)

    3.6.21

    Tobias G. Meier
    Center for Space and Habitability (CSH),
    University of Bern [Universität Bern](CH) and NCCR PlanetS
    tobias.meier@csh.unibe.ch

    Dr. Dan J. Bower
    Center for Space and Habitability (CSH),
    University of Bern [Universität Bern](CH) and NCCR PlanetS
    daniel.bower@csh.unibe.ch

    1
    This artist’s illustration represents the possible interior dynamics of the super-Earth exoplanet LHS 3844b. The planet’s interior properties and the strong stellar irradiation might lead to a hemispheric tectonic regime. © University of Bern [Universität Bern](CH) Credit: Thibaut Roger.

    Until now, researchers have found no evidence of global tectonic activity on planets outside our solar system. Under the leadership of the University of Bern [Universität Bern](CH) and the National Center of Competence in Research NCCR PlanetS(CH), scientists have now found that the material inside planet LHS 3844b flows from one hemisphere to the other and could be responsible for numerous volcanic eruptions on one side of the planet.

    On Earth, plate tectonics is not only responsible for the rise of mountains and earthquakes.

    The tectonic plates of the world were mapped in 1996, USGS.

    It is also an essential part of the cycle that brings material from the planet’s interior to the surface and the atmosphere, and then transports it back beneath the Earth’s crust. Tectonics thus has a vital influence on the conditions that ultimately make Earth habitable.

    Until now, researchers have found no evidence of global tectonic activity on planets outside our solar system. A team of researchers led by Tobias Meier from the Center for Space and Habitability (CSH) at the University of Bern [Universität Bern](CH) and with the participation of ETH Zürich [Eidgenössische Technische Hochschule Zürich)](CH), the University of Oxford(UK) and the National Center of Competence in Research NCCR PlanetS(CH) has now found evidence of the flow patterns inside a planet, located 45 light-years from Earth: LHS 3844b. Their results were published in The Astrophysical Journal Letters.

    An extreme contrast and no atmosphere

    “Observing signs of tectonic activity is very difficult, because they are usually hidden beneath an atmosphere”, Meier explains. However, recent results suggested that LHS 3844b probably does not have an atmosphere. Slightly larger than Earth and likely similarly rocky, it orbits around its star so closely that one side of the planet is in constant daylight and the other in permanent night – just like the same side of the Moon always faces the Earth. With no atmosphere shielding it from the intense radiation, the surface gets blisteringly hot: it can reach up to 800°C on the dayside. The night side, on the other hand, is freezing. Temperatures there might fall below minus 250°C. “We thought that this severe temperature contrast might affect material flow in the planet’s interior”, Meier recalls.

    To test their theory, the team ran computer simulations with different strengths of material and internal heating sources, such as heat from the planet’s core and the decay of radioactive elements. The simulations included the large temperature contrast on the surface imposed by the host star.

    Flow inside the planet from one hemisphere to the other

    “Most simulations showed that there was only upwards flow on one side of the planet and downwards flow on the other. Material therefore flowed from one hemisphere to the other”, Meier reports. Surprisingly, the direction was not always the same. “Based on what we are used to from Earth, you would expect the material on the hot dayside to be lighter and therefore flow upwards and vice versa”, co-author Dan Bower at the University of Bern and the NCCR PlanetS explains. Yet, some of the teams’ simulations also showed the opposite flow direction. “This initially counter-intuitive result is due to the change in viscosity with temperature: cold material is stiffer and therefore doesn’t want to bend, break or subduct into the interior. Warm material, however, is less viscous – so even solid rock becomes more mobile when heated – and can readily flow towards the planet’s interior”, Bower elaborates. Either way, these results show how a planetary surface and interior can exchange material under conditions very different from those on Earth.

    A volcanic hemisphere

    Such material flow could have bizarre consequences. “On whichever side of the planet the material flows upwards, one would expect a large amount of volcanism on that particular side”, Bower points out. He continues “similar deep upwelling flows on Earth drive volcanic activity at Hawaii and Iceland”. One could therefore imagine a hemisphere with countless volcanoes – a volcanic hemisphere so to speak – and one with almost none.

    “Our simulations show how such patterns could manifest, but it would require more detailed observations to verify. For example, with a higher-resolution map of surface temperature that could point to enhanced outgassing from volcanism, or detection of volcanic gases. This is something we hope future research will help us to understand”, Meier concludes.

    See the full article here .

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    Please help promote STEM in your local schools.

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    University of Bern [Universität Bern](CH) is a university in the Swiss capital of Bern and was founded in 1834. It is regulated and financed by the Canton of Bern. It is a comprehensive university offering a broad choice of courses and programs in eight faculties and some 150 institutes. With around 17,512 students, Universität Bern is the third biggest University in Switzerland.

    Universität Bern operates at three levels: university, faculties and institutes. Other organizational units include interfaculty and general university units. The university’s highest governing body is the Senate, which is responsible for issuing statutes, rules and regulations. Directly answerable to the Senate is the University Board of Directors, the governing body for university management and coordination. The Board comprises the Rector, the Vice-Rectors and the Administrative Director. The structures and functions of the University Board of Directors and the other organizational units are regulated by the Universities Act. Universität Bern offers about 39 bachelor and 72 master programs, with enrollments of 7,747 and 4,523, respectively. The university also has 2,776 doctoral students. Around 1,561 bachelor, 1,489 master’s degree students and 570 PhD students graduate each year. For some time now, the university has had more female than male students; at the end of 2016, women accounted for 56% of students.

     
  • richardmitnick 4:03 pm on January 19, 2021 Permalink | Reply
    Tags: "Going with the grains to explain a fundamental tectonic force", Plate Tectonics, , Tiny mineral grains — squeezed and mixed over millions of years — set in motion the chain of events that plunge massive tectonic plates deep into the Earth’s interior.,   

    From Yale University: “Going with the grains to explain a fundamental tectonic force” 

    From Yale University

    January 18, 2021
    Science contact
    Fred Mamoun
    fred.mamoun@yale.edu
    203-436-2643

    Writer
    Jim Shelton

    1
    Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Credit: Wikipedia.

    A new study suggests that tiny, mineral grains — squeezed and mixed over millions of years — set in motion the chain of events that plunge massive tectonic plates deep into the Earth’s interior.

    The theory, proposed by Yale scientists David Bercovici and Elvira Mulyukova, may provide an origin story for subduction, one of the most fundamental forces responsible for the dynamic nature of the planet.

    The study appears in the PNAS.

    Subduction occurs when one tectonic plate slides underneath another plate and then sinks into the Earth’s mantle. Its role in major geological processes is immense: It is the main engine for tectonic motion. It builds mountains, triggers earthquakes, forms volcanoes, and drives the geologic carbon cycle.

    The tectonic plates of the world were mapped in 1996, USGS.

    Yet researchers have been uncertain about what initiates subduction.

    “Why Earth even has subduction, unlike other terrestrial planets as far as we know, is a mystery,” said Bercovici, Yale’s Frederick William Beinecke Professor and chair of Earth and Planetary Sciences.

    “Mantle rock near the surface that has cooled for hundreds of millions of years has two competing effects,” he said. “While it’s gotten colder and heavier and wants to sink, it’s also gotten stiffer and doesn’t want to sink. The stiffening effect should win out, as it does on most planets, but on Earth, for some reason, it doesn’t.”

    2
    A conceptual sketch of the ocean basin setting for the new model. Inset images from a computer model show mineral fraction, grain size, and weakness. Credit: Elvira Mulyukova and David Bercovici.

    According to the theoretical model developed by Bercovici and Mulyukova, a research scientist at Yale, subduction may initiate at the margins between Earth’s sea floor and continents.

    The model shows that tectonic stresses in an oceanic plate cause its mineral grains to mix with each other, become damaged, and eventually shrink. Over a period of approximately 100 million years, this process weakens the oceanic plate and makes it susceptible to vertical shear and bending — which are associated with the start of subduction.

    “The real bottleneck for tectonic plate activity on a terrestrial planet is how fast its massive, rocky layers can deform,” said Mulyukova. “The rocks can deform only as fast as their tiny mineral grains allow. Our model explains how these changes in mineral grains can dramatically weaken the rock and make subduction possible on a planet like Earth.”

    This research was supported by a grant from the National Science Foundation.

    See the full article here .

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    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

     
  • richardmitnick 11:24 am on January 14, 2021 Permalink | Reply
    Tags: , , , Plate Tectonics   

    From Science News: “How the Earth-shaking theory of plate tectonics was born” 

    From Science News

    1.13.21
    Carolyn Gramling

    1
    Scientists have peppered the planet with seismometers that can detect the rumble of moving magma within a volcano, and GPS stations can spot changes in land elevation as magma swells below. But anticipating eruptions remains tricky. Credit: BRUCE DAVIDSON/NATURE PICTURE LIBRARY/ALAMY.

    Pure insights plus a boom in data transformed our understanding of Earth.

    Some great ideas shake up the world. For centuries, the outermost layer of Earth was thought to be static, rigid, locked in place. But the theory of plate tectonics has rocked this picture of the planet to its core. Plate tectonics reveals how Earth’s surface is constantly in motion, and how its features — volcanoes, earthquakes, ocean basins and mountains — are intrinsically linked to its hot interior.

    The tectonic plates of the world were mapped in 1996, USGS.

    The planet’s familiar landscapes, we now know, are products of an eons-long cycle in which the planet constantly remakes itself.

    When plate tectonics emerged in the 1960s it became a unifying theory, “the first global theory ever to be generally accepted in the entire history of earth science,” writes Harvard University science historian Naomi Oreskes, in the introduction to Plate Tectonics: An Insider’s History of the Modern Theory of the Earth. In 1969, geophysicist J. Tuzo Wilson compared the impact of this intellectual revolution in earth science to Einstein’s general theory of relativity, which had produced a similar upending of thought about the nature of the universe.

    Plate tectonics describes how Earth’s entire, 100-kilometer-thick outermost layer, called the lithosphere, is broken into a jigsaw puzzle of plates — slabs of rock bearing both continents and seafloor — that slide atop a hot, slowly swirling inner layer. Moving at rates between 2 and 10 centimeters each year, some plates collide, some diverge and some grind past one another. New seafloor is created at the center of the oceans and lost as plates sink back into the planet’s interior. This cycle gives rise to many of Earth’s geologic wonders, as well as its natural hazards.

    “It’s amazing how it tied the pieces together: seafloor spreading, magnetic stripes on the seafloor … where earthquakes form, where mountain ranges form,” says Bradford Foley, a geodynamicist at Penn State. “Pretty much everything falls into place.”

    With so many lines of evidence now known, the theory feels obvious, almost inevitable. But the conceptual journey from fixed landmasses to a churning, restless Earth was long and circuitous, punctuated by moments of pure insight and guided by decades of dogged data collection.

    Continents adrift

    In 1912, German meteorologist Alfred Wegener proposed at a meeting of Frankfurt’s Geological Association that Earth’s landmasses might be on the move. At the time, the prevailing idea held that mountains formed like wrinkles on the planet as it slowly lost the heat of formation and its surface contracted. Instead, Wegener suggested, mountains form when continents collide as they drift across the planet’s surface. Although now far-flung, the continents were once joined together as a supercontinent Wegener dubbed Pangaea, or “all-Earth.” This would explain why rocks of the same type and age, as well as identical fossils, are found on either side of the Atlantic Ocean, for example.

    2
    The San Andreas Fault (shown) is the boundary between the Pacific and North American plates. Credit: KEVIN SCHAFER/ALAMY.

    This idea of drifting continents intrigued some scientists. Many others, particularly geologists, were unimpressed, hostile, even horrified. Wegener’s idea, detractors thought, was too speculative, not grounded enough in prevailing geologic principles such as uniformitarianism, which holds that the same slow-moving geologic forces at work on Earth today must also have been at work in the past. The principle was thought to demand that the continents be fixed in place.

    3
    In 1989, a slip of the San Andreas Fault triggered a magnitude 6.9 earthquake that rocked the San Francisco Bay area, causing 63 deaths and billions of dollars in damag. Credit: David Weintraub/Science Source.

    German geologist Max Semper disdainfully wrote in 1917 [JSTOR] that Wegener’s idea “was established with a superficial use of scientific methods, ignoring the various fields of geology,” adding that he hoped Wegener would turn his attention to other fields of science and leave geology alone.“O holy Saint Florian, protect this house but burn down the others!” he wrote sardonically.

    The debate between “mobilists” and “fixists” raged on through the 1920s, picking up steam as it percolated into English-speaking circles. In 1926, at a meeting in New York City of the American Association of Petroleum Geologists, geologist Rollin T. Chamberlin dismissed Wegener’s hypothesis as a mishmash of unrelated observations. The idea, Chamberlin said, “is of the foot-loose type, in that it takes considerable liberty with our globe, and is less bound by restrictions or tied down by awkward, ugly facts than most of its rival theories.”

    One of the most persistent sticking points for Wegener’s idea, now called continental drift, was that it couldn’t explain how the continents moved. In 1928, English geologist Arthur Holmes came up with a potential explanation for that movement. He proposed that the continents might be floating like rafts atop a layer of viscous, partially molten rocks deep inside Earth. Heat from the decay of radioactive materials, he suggested, sets this layer to a slow boil, creating large circulating currents within the molten rock that in turn slowly shift the continents about.

    Holmes admitted he had no data to back up the idea, and the geology community remained largely unconvinced of continental drift. Geologists turned to other matters, such as developing a magnitude scale for earthquake strength and devising a method to precisely date organic materials using the radioactive form of carbon, carbon-14.

    Data flood in

    Rekindled interest in continental drift came in the 1950s from evidence from an unexpected source — the bottom of the oceans. World War II had brought the rapid development of submarines and sonar, and scientists soon put the new technologies to work studying the seafloor. Using sonar, which pings the seafloor with sound waves and listens for a return pulse, researchers mapped out the extent of a continuous and branching underwater mountain chain with a long crack running right down its center. This worldwide rift system snakes for over 72,000 kilometers around the globe, cutting through the centers of the world’s oceans.

    Armed with magnetometers for measuring magnetic fields, researchers also mapped out the magnetic orientation of seafloor rocks — how their iron-bearing minerals are oriented relative to Earth’s field. Teams discovered that the seafloor rocks have a peculiar “zebra stripe” pattern: Bands of normal polarity, whose magnetic orientation corresponds to Earth’s current magnetic field, alternate with bands of reversed polarity. This finding suggests that each of the bands formed at different times.

    3
    The Pacific Ocean’s Mariana Trench is the deepest known subduction zone, where a tectonic plate sinks back into Earth’s interior. Here, the Deep Discoverer explores the trench at a depth of 6,000 meters in 2016. Credit: NOAA OFFICE OF OCEAN EXPLORATION AND RESEARCH.

    Meanwhile, growing support for the detection and banning of underground nuclear testing also created an opportunity for seismologists: the chance to create a global, standardized network of seismograph stations [USGS]. By the end of the 1960s, about 120 different stations were installed in 60 different countries, from the mountains of Ethiopia’s Addis Ababa to the halls of Georgetown University in Washington, D.C., to the frozen South Pole. Thanks to the resulting flood of high-quality seismic data, scientists discovered and mapped rumbles along the mid-ocean rift system, now called mid-ocean ridges, and beneath the trenches. The quakes near very deep ocean trenches were particularly curious: They originated much deeper underground than scientists had thought possible. And the ridges were very hot compared with the surrounding seafloor, scientists learned by using thin steel probes inserted into cores drilled from shipboard into the seafloor.

    In the early 1960s, two researchers working independently, geologist Harry Hess and geophysicist Robert S. Dietz, put the disparate clues together — and added in Holmes’ old idea of an underlying layer of circulating currents within the hot rock. The mid-ocean ridges, each asserted, might be where circulation pushes hot rock toward the surface. The powerful forces drive pieces of Earth’s lithosphere apart. Into the gap, lava burbles up — and new seafloor is born. As the pieces of lithosphere move apart, new seafloor continues to form between them, called “seafloor spreading.”

    4
    Research suggests that volcanic island chains form as plates move over upwellings of magma. But the origin of the Hawaiian Islands (Kilauea volcano shown) and other similar chains remains something of a geologic puzzle. Credit:ART WOLFE/GETTY IMAGES.

    The momentum culminated in a two-day gathering of perhaps just 100 earth scientists in 1966, held at the Goddard Institute for Space Studies in New York. “It was quite clear, at this conference in New York, that everything was going to change,” University of Cambridge geophysicist Dan McKenzie told the Geological Society of London in 2017 in a reflection on the meeting.

    But going in, “no one had any idea” that this meeting would become a pivotal moment for the earth sciences, says seismologist Lynn Sykes of Columbia University. Sykes, then a newly minted Ph.D., was one of the invitees; he had just discovered a distinct pattern in the earthquakes at mid-ocean ridges. This pattern showed that the seafloor on either side of the ridges was pulling apart, a pivotal piece of evidence for plate tectonics.

    At the meeting, talk after talk piled data on top of data to support seafloor spreading, including Sykes’ earthquake data and those symmetrical patterns of zebra stripes. It soon became clear that these findings were building toward one unified narrative: Mid-ocean ridges were the birthplaces of new seafloor, and deep ocean trenches were graves where old lithosphere was reabsorbed into the interior. This cycle of birth and death had opened and closed the oceans over and over again, bringing the continents together and then splitting them apart.

    The evidence was overwhelming, and it was during this conference “that the victory of mobilism was clearly established,” geophysicist Xavier Le Pichon, previously a skeptic of seafloor spreading, wrote in 2001 in his retrospective essay My conversion to plate tectonics, included in Oreskes’ book.

    Plate tectonics emerges

    The whole earth science community became aware of these findings the following spring, at the American Geophysical Union’s annual meeting. Wilson laid out the various lines of evidence for this new view of the world to a much larger audience in Washington, D.C. By then, there was remarkably little pushback from the community, Sykes says: “Right away, they accepted it, which was surprising.”

    Scientists now knew that Earth’s seafloor and continents were in motion, and that ridges and trenches marked the edges of large blocks of lithosphere. But how were these blocks moving, all in concert, around the planet? To plot out the choreography of this complex dance, two separate groups seized upon a theorem devised by mathematician Leonhard Euler way back in the 18th century. The theorem showed that a rigid body moves around a sphere as though it is rotating around an axis. McKenzie and geophysicist Robert Parker used [Nature] this theorem to calculate the dance of the lithospheric blocks — the plates. Unbeknownst to them, geophysicist W. Jason Morgan independently came up with a similar solution [JGR].

    5
    Shifting landmasses — such as the opening of the Drake Passage between South America and Antarctica (icebergs around Elephant Island shown) — can alter currents, and climates. Credits: NASA IMAGE BY JEFF SCHMALTZ, LANCE/EOSDIS RAPID RESPONSE.

    With this last piece, the unifying theory of plate tectonics was born. The hoary wrangling over continental drift now seemed not only antiquated, but also “a sobering antidote to human self-confidence,” physicist Egon Orowan told Science News in 1970.

    People have benefited greatly from this clearer vision of Earth’s workings, including being able to better prepare for earthquakes, tsunamis and volcanoes. Plate tectonics has also shaped new research across the sciences, offering crucial information about how the climate changes and about the evolution of life on Earth.

    And yet there’s still so much we don’t understand, such as when and how the restless shifting of Earth’s surface began — and when it might end. Equally puzzling is why plate tectonics doesn’t appear to happen elsewhere in the solar system, says Lindy Elkins-Tanton, a planetary scientist at Arizona State University in Tempe. “How can something be a complete intellectual revolution and also inexplicable at the same time?”

    6
    Jupiter’s frozen moon Europa (shown) has its own form of icy plate tectonics.Credit: NASA/JPL-Caltech, SETI Institute.

    7
    Signs of plate tectonics are clearly visible on Earth’s surface (Piqiang Fault in China’s Xinjiang Province shown). Scientists wonder whether similar features on other planets could be clues to habitability.Credit: NASA.

    8
    Mars shows signs of volcanic activity (Olympus Mons shown) but no known plate tectonics.Credit: NASA/JPL.

    See the full article here.


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  • richardmitnick 12:02 am on January 12, 2021 Permalink | Reply
    Tags: "Rock magnetism uncrumples the Himalayas’ complex collision zone", An epic continent-continent collision that took place millions of years ago and changed the Earth affecting its climate and weather patterns., , As lava cools and rock forms it captures a signature of the Earth’s magnetic field which runs north-south toward Earth’s magnetic poles., , , India first collided with a volcanic island chain (similar to the Mariana Islands today) and then with Eurasia up to 10 million years later than is generally accepted., Kohistan-Ladakh arc, , Neotethys Ocean plate, , Plate Tectonics, The Himalayas are the textbook example of a continent-continent collision and an excellent laboratory for studying mountain-building events and tectonics, The imposing 1400-mile Himalayan mountain range separates the plains of the Indian subcontinent from the Tibetan Plateau., The Kshiroda plate and the Trans-Tethyan subduction zone (TTSZ)., The Neotethys Ocean plate began subducting into Earth’s mantle under Eurasia., The question of how the Indian and Eurasian tectonic plates collided and the mountains came into existence is one that scientists are still unfolding., This finding is contrary to the long-held view that the India-Eurasia collision was a single-stage event that started at 55-60 million years ago.   

    From MIT: “Rock magnetism uncrumples the Himalayas’ complex collision zone” 

    MIT News

    From MIT News

    January 7, 2021
    Lauren Hinkel Department of Earth, Atmospheric and Planetary Sciences (EAPS)

    MIT EAPS researchers find the impressive mountain range formed over a series of impacts, not a single event, as previously thought.

    1
    Craig Martin holds a pickaxe in the Himalayan mountains. Credit: Craig Martin.

    With some of the world’s tallest peaks, Asia’s “the abode of snow” region is a magnet for thrill seekers, worshipers, and scientists alike. The imposing 1,400-mile Himalayan mountain range that separates the plains of the Indian subcontinent from the Tibetan Plateau is the scene of an epic continent-continent collision that took place millions of years ago and changed the Earth, affecting its climate and weather patterns. The question of how the Indian and Eurasian tectonic plates collided, and the mountains came into existence, is one that scientists are still unfolding. Now, new research published in PNAS and led by MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS) confirms that it’s more complicated than previously thought.

    “The Himalayas are the textbook example of a continent-continent collision and an excellent laboratory for studying mountain-building events and tectonics,” says EAPS graduate student Craig Martin, the paper’s lead author.

    The story begins around 135 million years ago, when the Neotethys Ocean separated the tectonic plates of India and Eurasia by 4,000 miles. The common view of geologists is that the Neotethys Ocean plate began subducting into Earth’s mantle under Eurasia, on its southern border, pulling India north and the tectonic plates above it together to ultimately form the Himalayas in a single collision event around 55-50 million years ago. However, geologic evidence suggested that the high rate of subduction observed didn’t seem to quite fit this hypothesis, and model reconstructions place the continental plates thousands of kilometers apart at the time of this inferred collision. To account for the time delay and subduction strength required, MIT’s Oliver Jagoutz, associate professor of geology, and Leigh “Wiki” Royden, the Cecil and Ida Green Professor of Geology and Geophysics, proposed that because of the high speed, orientation, and location of the final continental collision, there needed to be another oceanic plate and subduction zone in the middle of the ocean, called the Kshiroda plate and the Trans-Tethyan subduction zone (TTSZ), which ran east to west. Additionally, EAPS geologists and others postulated that an arc of volcanic islands, like the Marianas, existed in between the two, called the Kohistan-Ladakh arc. Located near the equator, they took the brunt of the force from India before being squished between the two continental crusts.

    Tiny magnets point the way

    This chain of events, its timing and geological configuration, was speculation based on models and some geological evidence until EAPS researchers tested it — but first, they needed rocks. Along with professor of planetary sciences Ben Weiss of the MIT Paleomagnetism Laboratory, Martin, Jagoutz, Royden, and their colleagues visited northwest India’s Ladakh region, bordering the Eurasian plate. Over multiple excursions, the team, which included EAPS undergraduate Jade Fischer for one trip, scrambled over outcrops and drilled rock cores, slightly larger than the size of a cork. As they pulled them out, the geologists and paleomagnetism experts marked the samples’ orientation in the rock layer and its location in order to determine when and where on Earth the rock was formed. The team was looking for evidence showing whether a volcano, which was active around 66-61 million years ago, was part of a volcanic island chain in the ocean south of Eurasia, or part of the Eurasian continent. This would also help determine the plausibility of a double subduction zone scenario.

    Back in the lab, the MIT researchers used rock dating and paleomagnetism to understand this ancient geologic car crash. They leveraged the fact that, as lava cools and rock forms, it captures a signature of the Earth’s magnetic field, which runs north-south toward Earth’s magnetic poles. If rock forms near the equator, the magnetization (electron) spins in its iron-bearing minerals, like magnetite and hematite, will be oriented parallel to the ground. As you move further away from the equator, the rock’s magnetization will tip into the Earth; however subsequent heating and remagnetization can print over the original signature.

    After checking for this, and correcting for the tilt of the bedrock at the site, Martin and his colleagues were able to pinpoint the latitude at which the rocks were created. Uranium-lead dating of the samples’ zircon minerals provided the other piece of the puzzle to constrain the timing of formation. If there was a single collision, these rocks would have formed at a latitude somewhere around 20 degrees north, above the equator, near Eurasia; if the islands existed, they would have originated near the equator.

    “It’s cool that we can reconstruct the deep-time atlas of the world using the tiny magnets preserved in rocks,” says Martin.

    A two-part system

    With their time and latitudinal measurements and models, the MIT researchers found the evidence they were looking for — the presence of an island chain and double subduction system. From 80 to likely 55-50 million years ago, the Neotethys Ocean was subducted in two locations: along the Eurasian plate’s southern edge (the Kshiroda plate sank) and the mid-ocean TTSZ, just south of the Kshiroda plate and near the equator. Together, these events closed the ocean, and the tectonic activity worked with erosion and weathering to sequester and draw down carbon, until the Paleocene Epoch (66-23.03 million years ago). “The presence of two subduction zones and the timing of their destruction at low latitudes explains the cooling global climate in the Cenozoic (66 million years ago to present day),” says Martin.

    Most importantly: “Our results mean that instead of India colliding directly with Eurasia to form the Himalayas, India first collided with a volcanic island chain (similar to the Mariana Islands today), and then with Eurasia up to 10 million years later than is generally accepted,” says Martin. This is because Kohistan-Ladakh arc and India collision slowed the India-Eurasia convergence rate, which kept decreasing until 45-40 million years ago when the final collision occurred. “This finding is contrary to the long-held view that the India-Eurasia collision was a single-stage event that started at 55-60 million years ago,” says Martin. “Our results strongly support Oli and Wiki’s double subduction hypothesis explaining why India moved north so anomalously fast in the Cretaceous period.”

    Further, Martin, Jagoutz, Royden, and Weiss were able to determine the maximum extent of the Indian plate before it was forced under Eurasia. The convergence between India and Eurasia since 50-55 million years ago was around 2,800-3,600 kilometers. Much of this is explained by the subduction of the Kshiroda plate, which the MIT researchers estimated to be roughly 1,450 kilometers wide, at the time of the first collision with the island arc, 55-50 million years ago. After the first stage of collision between the island chain and India, the Kshiroda plate continued to disappear underneath Eurasia. Then, 15-10 million years later, as the two continents came together, the continental crust began shortening, folding, and thrusting rocks upward, the force of which caused observable changes to the composition and structure of the rocks. “Our results also directly constrain the size of the part of India ‘lost’ in the collision to less than 900 kilometers in the north-south direction, which is much less than the 2,000 kilometers previously required to explain the timing of collision.”

    The newly-gained insights into the mechanisms and geometry of such an archetypal mountain system have important implications for using the Himalayas to study continental collision, says Martin. Revising the number of subduction zones, the age of final collision, and the amount of continental crust involved in the formation of the Himalayas changes some key parameters required to accurately model the growth of mountain belts, the deformation of continental crust, and the relationships between plate tectonics and global climate.

    Martin hopes to take this further throughout the rest of his graduate studies by focusing in on the intensely deformed collision zone between the volcanic island chain and Eurasia. He hopes to understand the closure of the Kshiroda ocean and the geological structures produced during the continental collision.

    Not only is the finding impressive, but as Martin remarks, “I think it is cool to imagine idyllic tropical volcanic islands, with dinosaurs roaming around on them, having been sandwiched between two colliding tectonic plates and uplifted to form the roof of the world.”

    This study was funded, in part, by NSF Tectonics Program and MISTI-India.

    See the full article here .


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  • richardmitnick 12:41 pm on December 22, 2020 Permalink | Reply
    Tags: "Slowdown in plate tectonics may have led to Earth’s ice sheets", , , , , Plate Tectonics, , Seafloor spreading is captured in magnetic zones on the ocean floor.   

    From Science Magazine: “Slowdown in plate tectonics may have led to Earth’s ice sheets” 

    From Science Magazine

    Dec. 22, 2020
    Paul Voosen

    1
    The extrusion of fresh ocean crust at midocean ridges began to slacken 15 million years ago, perhaps cooling the planet.
    Credit: geogphotos/Alamy Stock Photo.

    In seafloor trenches around the world, slabs of old ocean crust fall in slow motion into the mantle, while fresh slabs are built at midocean ridges, where magma emerges at the seams between separating tectonic plates. The engine is relentless—but maybe not so steady: Beginning about 15 million years ago, in the late Miocene epoch, ocean crust production declined by one-third over 10 million years to a slow pace that pretty much continues to today, says Colleen Dalton, a geophysicist at Brown University who presented the work this month at a virtual meeting of the American Geophysical Union. “It’s a global phenomenon.”

    Although previous ocean-spreading records showed hints of a slowdown, nothing suggested such a steep decline, says Clint Conrad, a mantle dynamicist at the University of Oslo who is unaffiliated with the work. The lag was also widespread: Dalton found crust production slowed down or stayed steady at 15 of Earth’s 16 ocean ridges. And its effect on the climate may have been stark, Conrad says. “If you dramatically slow down plate tectonics in such a short time, you can put out a lot less carbon dioxide (CO2) gas from volcanism.” The slowdown corresponds to a 10°C drop in temperatures in the late Miocene, when ice sheets began to grow across Antarctica after a long hiatus.

    Seafloor spreading is captured in magnetic zones on the ocean floor. Every million years or so, Earth’s magnetic field flips, and this reversal is frozen in the rocks forged at the midocean ridges. Ship-based observations of the alternating magnetic “stripes” that result as slabs of ocean crust unfurl from the seafloor spreading centers helped give credence to the theory of plate tectonics in the 1960s.

    The ridges in the Atlantic and Indian oceans spread slowly, however, which means ships have been able to map these stripes with a temporal resolution of only about 10 million years. But geophysicists Charles DeMets of the University of Wisconsin, Madison, and Sergey Merkuryev of Saint Petersburg State University drew on previously unused data from Russian naval ships, which—like those of other nations—tow magnetometers to aid the hunt for enemy submarines. The new data sharpened the resolution in these ocean basins to 1 million years. “And it turns out there are surprising signals hiding in a lot of places that we didn’t know about,” says DeMets, who identified part of the slowdown in his records.

    Dalton and her colleagues added to the picture by assembling a complementary high-resolution record for the Pacific Ocean, where seafloor spreading is faster and more complex. With that global view, the slackening immediately became apparent. It appears the deceleration came in two waves, DeMets says: first between 12 million and 13 million years ago in the Pacific and then 7 million years ago in the Atlantic and Indian oceans.

    Maybe the subducting slabs stopped tugging as hard on the moving sea floor during this time, Dalton speculates, because they grew thinner or less dense. Or maybe the subduction zones, typically as long as the midocean ridges, shrunk in length, reducing their pull. Another possibility is that the zones changed their orientation, causing the subducting slabs to meet more resistance as they dove into the mantle, which has a kind of natural, grainlike wood. Or a slab could have broken off entirely, changing the flow of heat inside the mantle and altering the glide of the tectonic plates overhead, Conrad says. “Even if you change one plate, it affects all the plates.”

    By taking volcanic CO2 emissions tied to today’s ocean crust production and adjusting them for late Miocene speeds, the team found a drop in atmospheric CO2 that could plausibly explain the global cooling at the time. But Dalton says other explanations are possible—for example, ancient volcanic rocks, uplifted out of the ocean to form fresh mountain peaks in places like Indonesia, might have started to soak up more CO2. Both mechanisms likely explain some of the drop, says Nicholas Swanson-Hysell, a paleogeographer at the University of California, Berkeley. “But which is more important?”

    Beyond lowering CO2, the crustal slowdown would have reshaped Earth’s surface. With less seafloor volcanism, the midocean ridges would have been smaller, increasing the capacity of the oceans. Sea levels would have fallen by 22 meters, Dalton calculates, exposing vast new stretches of land. And as the volcanoes went quiet, the planet itself would have grown 5% less efficient at shedding its internal heat, losing some 1.5 terawatts of output—roughly equal to the production of 1500 nuclear power plants. That decline in heat flow wouldn’t have made much difference to atmospheric temperatures, but Dalton says it calls into question reconstructions of Earth’s cooling history that assume constant heat loss across the ages.

    Although there’s much to be teased out, it’s clear that, when viewed over relatively short geological time spans, there’s nothing constant about plate tectonics, says Karin Sigloch, a geophysicist at the University of Oxford.

    The tectonic plates of the world were mapped in 1996, USGS.

    “Variation should always be expected.” Slabs break, monster plumes of seafloor magma suddenly erupt—all with huge climatic repercussions for the thin biosphere clinging to life at the surface. Yet they are just burps in a planetary engine that churns away in a deep and hidden underworld.

    See the full article here .


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