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  • richardmitnick 6:02 pm on October 1, 2015 Permalink | Reply
    Tags: , , , Geology, , U Kansas   

    From Kansas: “Scientists refine hunt for Mars life by analyzing rock samples in Western U.S” 

    U Kansas bloc

    University of Kansas

    LAWRENCE — The search for life beyond Earth is one of the grandest endeavors in the history of humankind — a quest that could transform our understanding of our universe both scientifically and spiritually.

    Petrographic thin section made from core sample. This 30 micron thin slice of rock allows a view of the types of features thought to be microbial. Here, the blue layers are an epoxy added in to see void-space in the rock, and the grey is sediment. The morphology of the orange-brown layers are suggestive of microbial activity, such as they way they roll over themselves in the bottom left and smoothly drape over the triangular feature. This type of deposition demonstrates that the sediment had to have a degree of cohesive stickiness, such as that provided by the presence of microbial mats.

    With news coming this week that NASA has confirmed the presence of flowing saltwater on the surface of Mars, the hunt for life on the Red Planet has new momentum.

    “One of the many reasons this is exciting is that life as we currently know it requires water,” said Alison Olcott-Marshall, assistant professor of geology at the University of Kansas. “So the fact that it’s present at Mars means that the most basic and universal requirement for life was fulfilled.”

    In the journal Astrobiology, Olcott-Marshall recently has published an analysis of Eocene rocks found in the Green River Formation, a lake system extending over parts of Colorado, Utah and Wyoming.

    Marshall and co-author Nicholas A. Cestari, a masters student in her lab, found these Green River rocks have features that visually indicate the presence of life, and they argue that probes to Mars should identify similar indicators on that planet and double-check them through chemical analysis.

    “Once something is launched into space, it becomes much harder to do tweaks — not impossible, but much, much harder,” Olcott-Marshall said. “Scientists are still debating the results of some of the life-detection experiments that flew to Mars on the Viking Missions in the late ’70s, in a large part because of how the experiments were designed. Looking at Earth-based analogs lets us get some of these bumps smoothed out here on Earth, when we can revise, replicate and re-run experiments easily.”

    Petrographic thin section made from core sample. This 30 micron thin slice of rock allows a view of the types of features thought to be microbial, such as the layers that fold over themselves in the middle of the sample marked 2534.8’. This demonstrates that the sediment had to have a degree of cohesive stickiness, such as that provided by the presence of microbial mats.

    The researchers examined cored samples of rock from 50 million years ago that included sections of “microbial mats.”

    “Microbial mats are essentially the microbial world’s version of apartment buildings — they are layered communities of microbes, and each layer represents a different metabolic strategy,” Olcott-Marshall said. “Generally, the photosynthetic microbes are at the top, and then every successive layer makes use of the waste products of the level above. Thus, not only does a microbial mat contain a great deal of biology, but a great number of chemicals, pigments and metabolic products are made, which means lots of potential biosignatures.”

    At times during the Eocene, the Green River Formation’s water chemistry purged fish and other organisms from the lake, providing room for these microbes to thrive.

    “During these times, ‘microbialites’ formed — these are rocks thought to be made by microbial processes, essentially the preserved remnants of microbial mats. The Green River Formation has a wide variety of these structures, and these features are why we went looking in these rocks, as microbialites are one life-detection target on Mars.”

    First, the researchers visually inspected the cored samples for signs of biology by identifying geological signs associated with microbialites — such as “stromatolites.”

    “These are things like finely laminated sediments, where each lamination follows the ones below, or signs of cohesive sediment, things like layers that roll over onto themselves or are at an angle steeper than what gravity would allow,” Olcott-Marshall said. “These are all thought to be signs that microbes are helping hold sediment together.”

    If visual examination pointed to the presence of biology in sections of the rock cores, the researchers looked to confirm the presence of life. They powdered those rock samples in a ball mill, and then used hot organic solvents like methanol to remove any organic carbons that might have been preserved in the rocks. That solvent was then concentrated and analyzed with gas chromatography/mass spectroscopy.

    “GC/MS allows an identification of compounds, including organic molecules, preserved in a rock,” Olcott-Marshall said. “Viking was the first time that a GC/MS was sent to Mars, and there is one up there right now on Curiosity collecting data.”

    NASA Viking 2
    NASA/Viking 2

    NASA Mars Curiosity Rover
    NASA/Mars Curiosity Rover

    Through GC/MS, the researchers determined that rock structures appearing to be biological indeed hosted living organisms millions of years ago: analysis showed the presence of lipid biomarkers.

    “A lipid biomarker is the preserved remnant of a lipid, or a fat, once synthesized by an organism,” Olcott-Marshall said. “These can be simple or very complex. Different organisms make different lipids, so identifying the biomarker can often allow a deeper understanding of the biota or the environment present when a rock was formed. These are a type of biosignature.”

    The researchers said their results could be a powerful guide for sample selection on Mars.

    “There is a GC/MS on Curiosity right now, but there are only nine sample cups dedicated for looking for biomarkers like these,” Olcott-Marshall said. “It’s crucial those nine samples are ones most likely to guarantee success. Additionally, one of the goals of the planned 2020 rover mission is to identify samples for caching for eventual return to Earth. The amount of sample that can be returned is likely very small, thus, once again, doing our best to guarantee success is very important. What this shows is that we can use visual inspection to help us screen for these samples that are likely to be successful for further biosignature analysis.”

    She said microbial and non-microbial rocks are found in similar environments, with identical preservation histories for millions of years, and many of the same chemical parameters, such as amounts of organic carbon preserved in the rocks.

    “The only difference is that one rock is shaped in a way people have associated with biology, and sure enough, those rocks are the ones that seem to preserve the biosignatures, at least in the Green River,” she said.

    See the full article here.

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    U Kansas campus

    Since its founding, the University of Kansas has embodied the aspirations and determination of the abolitionists who settled on the curve of the Kaw River in August 1854. Their first goal was to ensure that the new Kansas Territory entered the union as a free state. Another was to establish a university.

    Nearly 150 years later, KU has become a major public research and teaching institution of 28,000 students and 2,600 faculty on five campuses (Lawrence, Kansas City, Overland Park, Wichita, and Salina). Its diverse elements are united by their mission to educate leaders, build healthy communities, and make discoveries that change the world.

    A member of the prestigious Association of American Universities since 1909, KU consistently earns high rankings for its academic programs. Its faculty and students are supported and strengthened by endowment assets of more than $1.44 billion. It is committed to expanding innovative research and commercialization programs.

    KU has 13 schools, including the only schools of pharmacy and medicine in the state, and offers more than 360 degree programs. Particularly strong are special education, city management, speech-language pathology, rural medicine, clinical child psychology, nursing, occupational therapy, and social welfare. Students, split almost equally between women and men, come from all 50 states and 105 countries and are about 15 percent multicultural. The University Honors Program is nationally recognized, and KU has produced 26 Rhodes Scholars, more than all other Kansas schools combined.

  • richardmitnick 7:20 am on August 10, 2015 Permalink | Reply
    Tags: , , Earth's Magnetic field, Geology   

    From Cosmos: “Earth’s early magnetic field locked in 4.2 billion-year-old crystals” 

    Cosmos Magazine bloc


    10 Aug 2015
    Belinda Smith

    An artist’s depiction of Earth’s magnetic field deflecting high-energy protons from the Sun four billion years ago (not to scale).Credit: Michael Osadciw / University of Rochester.

    Like tiny compasses frozen in time, ancient zircon gems from Western Australia have shown Earth’s magnetic field is at least four billion years old – more than 700 million years older than previous evidence suggested. Because the magnetic field protects the Earth’s atmosphere from destructive solar rays, it raises the possibility that life could have made its debut much earlier than previously thought.

    A North American team, led by John Tarduno at New York’s University of Rochester, found the young Earth had a chaotic magnetic field that was, at times, as strong as our field today. They reported their work in Science in July.

    It’s “astonishing to be able to probe the magnetic field that far back”, says Louis Moresi, a geoscientist at the University of Melbourne.

    Earth formed some 4.5 billion years ago, accreting from dust and proto-planetary fragments swirling around the Sun. Even in the near absolute zero temperatures of space, enough heat was trapped in the colliding mass to melt material in its core. Over time, the radioactive decay of uranium and other ‘hot’ elements has kept the core molten.

    Today, if you were to drill through the crust, you’d travel through 2,900 kilometres of rocky mantle before reaching the outer core. You’d then slither through 2,200 kilometres of liquid iron, before hitting a metallic inner core about 1,200 kilometres in diameter – a little smaller than the Moon. The inner core is kept solid by the enormous pressures at the centre of the Earth.

    It’s the liquid outer core, constantly stirred by convection currents, that generates our magnetic field. Just as hot air rises, hot iron rises towards Earth’s cooler surface, carrying heat that escapes through the mantle and crust. As the iron cools, it sinks, providing a constant stirring motion that generates our magnetic field.

    The mantle layer is vital to maintaining this motion. If it is too thin, the heat in the core dissipates quickly, along with the magnetic field. If it is too insulating, the vital convection currents shut down.

    Thanks to the Earth’s daily rotation and the stabilising solid inner core, the convection currents in the molten outer core have settled into spiralling columns that lie parallel to the Earth’s axis, giving us the elegant north-south dipole our compasses use today. What was it like in the Earth’s youth?

    It’s hard to say. Our dynamic planet’s surface is continually crushed, stretched and recycled – thanks to plate tectonics – and rock remnants from the Earth’s earliest days are scarce.

    The tectonic plates of the world were mapped in the second half of the 20th century.

    But thanks to a zircon crystal dug out of 4.4-billion-year-old sandstone on a Western Australian sheep ranch, we may have a clue. The University of Wisconsin-Madison-led study last year claimed the gemstone was born 100 million years after the Earth itself.

    For Tarduno and his team, that report raised an exciting possibility. They realised that like mosquitoes in amber, tiny iron oxide grains also known as magnetite would be trapped inside the zircon as it solidified and could have recorded the ancient magnetic field. His team returned to the same area and collected 25 zircon crystals dated from 3.3 to 4.2 billion years old, and examined them for microscopic magnetite flakes. But a super-sensitive instrument was needed to pick out the magnetic alignment in the grains.

    Enter the superconducting quantum interference device (the SQUID).

    SQUID superconducting quantum interference device

    This ultra-high-definition magnetometer can detect faint magnetic fields – as much as 100 billion times weaker than the energy needed to move a compass needle. The SQUID found the magnetite grains harboured magnetic fields of varying strengths – from the equivalent of today’s magnetic field, to 12% of its strength.

    A 4.4 billion-year-old zircon crystal from the Jack Hills region of Western Australia, which is the oldest bit of the Earth’s crust.Credit: John Valley

    Before this study, the oldest evidence for a magnetic field on Earth came from South African rocks dated at 3.2 and 3.45 billion years old. Two of the oldest zircons in Tarduno’s study were 750 million years older. “It’s amazing what they could get out of these little guys,” Moresi says, adding they really are “miracle crystals”.

    So why does the age of the magnetic field affect life’s appearance on Earth?

    Basically, the field shields us from our life-giver – the Sun. Streams of charged particles flow from the Sun, bombarding the inner planets and stripping away their water and atmosphere – unless a magnetic field is strong enough to deflect the onslaught.

    Tarduno points to our neighbour, Mars. The barren world once had a magnetic field, but no longer – nor any surface liquid water or atmosphere to speak of. Scientists think that around four billion years ago the Earth and Mars were battered by asteroids. On Mars, the onslaught over-heated its mantle. As the heat gradient between the core and mantle was lost, its core’s convection currents slowed and eventually stopped, switching off its magnetic shield and allowing the solar wind to whisk its atmosphere away. “It may also be a major reason why Mars was unable to sustain life,” he says.

    But the Earth was a little larger, and able to weather the storm. Ensconced in its protective magnetic bubble, life could begin to flourish.

    See the full article here.

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  • richardmitnick 1:53 pm on July 29, 2015 Permalink | Reply
    Tags: , , Geology   

    From ASU Via KJZZ: “Debate Continues Over Age Of The Grand Canyon” 

    ASU Bloc



    July 27, 2015
    Melissa Sevigny

    A view from the South Rim of the Grand Canyon. (Photo by Melissa Sevigny – KNAU)

    New research supports the long-held hypothesis that the Grand Canyon is as young as 6 million years. That’s what geologists originally believed before a different study claimed it was tens of millions of years older.

    The study, which was conducted by geologists at Arizona State University, compares the western Grand Canyon with the Grand Wash Cliffs. It found that the canyon is steeper than the cliffs, which suggests erosion started more recently.

    “So our conclusion is that it’s younger than the activity on the Grand Wash Fault,” said Andrew Darling, lead author of the study. “If the canyon’s younger than the fault, that would be consistent with the 6 million year old canyon age.”

    A previous study in 2012 revitalized research and debate when it claimed the Grand Canyon might be as old as 70 million years. That study looked at the decay of radioactive elements in rocks. The ASU study looked at geomorphology, particularly erosion rates.

    See the full article here.

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    ASU is the largest public university by enrollment in the United States.[11] Founded in 1885 as the Territorial Normal School at Tempe, the school underwent a series of changes in name and curriculum. In 1945 it was placed under control of the Arizona Board of Regents and was renamed Arizona State College.[12][13][14] A 1958 statewide ballot measure gave the university its present name.
    ASU is classified as a research university with very high research activity (RU/VH) by the Carnegie Classification of Institutions of Higher Education, one of 78 U.S. public universities with that designation. Since 2005 ASU has been ranked among the Top 50 research universities, public and private, in the U.S. based on research output, innovation, development, research expenditures, number of awarded patents and awarded research grant proposals. The Center for Measuring University Performance currently ranks ASU 31st among top U.S. public research universities.[15]

    ASU awards bachelor’s, master’s and doctoral degrees in 16 colleges and schools on five locations: the original Tempe campus, the West campus in northwest Phoenix, the Polytechnic campus in eastern Mesa, the Downtown Phoenix campus and the Colleges at Lake Havasu City. ASU’s “Online campus” offers 41 undergraduate degrees, 37 graduate degrees and 14 graduate or undergraduate certificates, earning ASU a Top 10 rating for Best Online Programs.[16] ASU also offers international academic program partnerships in Mexico, Europe and China. ASU is accredited as a single institution by The Higher Learning Commission.

    ASU Tempe Campus
    ASU Tempe Campus

  • richardmitnick 9:36 am on July 23, 2015 Permalink | Reply
    Tags: , Geology,   

    From OSU: “Satellites peer into rock 50 miles beneath Tibetan Plateau” 


    Ohio State University

    July 21, 2015
    Pam Frost Gorder

    Topography (left) and a shaded relief map (right) of the rock deep beneath the Tibetan Plateau. Color indicates kilometers below Earth’s surface. Image by Younghong Shin of the Korea Institute of Geosciences and Mineral Resource, courtesy of The Ohio State University.

    Gravity data captured by satellite has allowed researchers to take a closer look at the geology deep beneath the Tibetan Plateau.

    The analysis, published in the journal Nature Scientific Reports, offers some of the clearest views ever obtained of rock moving up to 50 miles below the plateau, in the lowest layer of Earth’s crust.

    There, the Indian tectonic plate presses continually northward into the Eurasian tectonic plate, giving rise to the highest mountains on Earth—and deadly earthquakes, such as the one that killed more than 9,000 people in Nepal earlier this year.

    The study supports what researchers have long suspected: Horizontal compression between the two continental plates is the dominant driver of geophysical processes in the region, said C.K. Shum, professor and Distinguished University Scholar in the Division of Geodetic Science, School of Earth Sciences at The Ohio State University and a co-author of the study.

    “The new gravity data onboard the joint NASA-German Aerospace Center GRACE gravimeter mission and the European Space Agency’s GOCE gravity gradiometer missionenabled scientists to build global gravity field models with unprecedented accuracy and resolution, which improved our understanding of the crustal structure,” Shum said. “Specifically, we’re now able to better quantify the thickening and buckling of the crust beneath the Tibetan Plateau.”

    NASA Grace

    ESA GOCE Spacecraft

    Younghong Shin

    Shum is part of an international research team led by Younghong Shin of the Korea Institute of Geosciences and Mineral Resource. With other researchers in Korea, Italy and China, they are working together to conduct geophysical interpretations of the Tibetan Plateau geodynamics using the latest combined gravity measurements by the GOCE gravity gradiometer and the GRACE gravimeter missions.

    Satellites such as GRACE and GOCE measure small changes in the force of gravity around the planet. Gravity varies slightly from place to place in part because of an uneven distribution of rock in Earth’s interior.

    The resulting computer model offers a 3-D reconstruction of what’s happening deep within the earth.

    As the two continental plates press together horizontally, the crust piles up. Like traffic backing up on a congested freeway system, the rock follows whatever side roads may be available to relieve the pressure.

    But unlike cars on a freeway, the rock beneath Tibet has two additional options for escape. It can push upward to form the Himalayan mountain chain, or downward to form the base of the Tibetan Plateau.

    The process takes millions of years, but caught in the 3-D image of the computer model, the up-and-down and side-to-side motions create a complex interplay of wavy patterns at the boundary between the crust and the mantle, known to researchers as the Mohorovičić discontinuity, or “Moho.”

    “What’s particularly useful about the new gravity model is that it reveals the Moho topography is not random, but rather has a semi-regular pattern of ranges and folds, and agrees with the ongoing tectonic collision and current crustal movement measured by GPS,” Shin said.

    As such, the researchers hope that the model will provide new insights into the analysis of collisional boundaries around the world.

    Co-author Carla Braitenberg of the University of Trieste said that the study has already helped explain one curious aspect of the region’s geology: the sideways motion of the Tibetan Plateau. While India is pushing the plateau northward, GPS measurements show that portions of the crust are flowing eastward and even turning to the southeast.

    “The GOCE data show that the movement recorded at the surface has a deep counterpart at the base of the crust,” Braitenberg said. Connecting the rock flow below to movement above will help researchers better understand the forces at work in the region.

    Those same forces led to the deadly Nepal earthquake in April 2015. But Shum said that the new model almost certainly won’t help with earthquake forecasting—at least not in the near future.

    “I would say that we would understand the mechanism more if we had more measurements,” he said, but such capabilities “would be very far away.”

    Even in California—where, Shum pointed out, different tectonic processes are at work than in Tibet—researchers are unable to forecast earthquakes, despite having abundant GPS, seismic and gravity data. Even less is known about Tibet, in part because the rough terrain makes installing GPS equipment difficult.

    Other co-authors on the study included Sang Mook Lee of Seoul National University; Sung-Ho Na of the University of Science and Technology in Daejeon, Korea;

    Kwang Sun Choi of Pusan National University; Houtse Hsu of the Institute of Geodesy & Geophysics, Chinese Academy of Sciences; and Young-Sue Park and Mutaek Lim of the Korea Institute of Geosciences and Mineral Resource.

    This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources, funded by the Ministry of Science, ICT and Future Planning of Korea. Shum was partially supported by NASA’s GRACE Science Team Program and Concept in Advanced Geodesy Program. Braitenberg was partially supported by the European Space Agency’s Center for Earth Observation as part of the GOCE User ToolBox project.

    See the full article here.

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  • richardmitnick 8:20 am on June 5, 2015 Permalink | Reply
    Tags: , , Geology,   

    From Michigan Tech: “Clues to the Earth’s Ancient Core” 

    Michigan Tech bloc

    Michigan Technical University

    June 4, 2015
    Allison Mills

    Aleksey Smirnov drills into an outcrop in Australia’s Widgiemooltha dike swarm.

    Old rocks hold on to their secrets. Now, a geophysicist at Michigan Technological University has unlocked clues trapped in the magnetic signatures of mineral grains in those rocks.. These clues will help clear up the murky history of the Earth’s early core.

    The journal Earth and Planetary Science Letters published a paper on the subject earlier this year. Aleksey Smirnov, an associate professor of geophysics and adjunct associate professor of physics at Michigan Tech, led the study. The work is a part of a large research program led by Smirnov and supported by the National Science Foundation (NSF), including his CAREER Award, a prestigious NSF grant. Through this work, he has traveled the world seeking rocks that provide insight into the ancient earth’s core.

    Earth’s Ancient Geodynamo

    The magnetic field comes from the earth’s core: The solid inner core, made of iron, spins and powers convective currents in the liquid outer core. Those currents create the magnetic field, and the system is called the geodynamo.

    “At any point, the field can be described by its direction and strength,” Smirnov says, adding that the modern magnetic field is weaker than that of a refrigerator magnet and that intensity has changed throughout geologic time. “What we call paleointensity in our paper refers to the field’s strength,” he explains.

    Smirnov and his co-author, David Evans of Yale University, examined the paleointensity measurements of rocks more than two billion years old. Rocks that old record a magnetic field from a rather mysterious geodynamo.

    That’s because the core didn’t always have a solid center — it used to be all liquid. And being liquid would make for a weak, chaotic magnetic field.

    “What happened at some point, because the earth is constantly cooling, the center formed a small, solid inner core,” Smirnov says. “But this event is uncertain in terms of timing.”

    A number of models analyze what this timing could have been, but they estimate any time between half a billion years ago and three billion years ago — which is like saying an adolescent will hit puberty sometime between ages 8 to 30. To better pinpoint the timing of the inner core’s formation, Smirnov scours the world for old Precambrian rocks.

    Magnetic Records in Rocks

    Smirnov focuses on rocks that are not just old, but magnetic, and he tests the samples in the Earth Magnetism Lab at Michigan Tech. Within the lab is a room, built above the concrete floor and boxed in with a special steel alloy — it’s a metal-free zone. Inside the room, Smirnov uses a magnetometer: a device that measures magnetic properties in rocks and, more specifically, their iron-rich minerals.


    Magnetite is an iron oxide with magnetic properties, and when it crystallizes in a rock, it records the strength and orientation of the earth’s magnetic field. Some rocks record this better than others; an ideal rock cools fast and is well-preserved.

    “Because of the rarity of well-preserved extrusive Precambrian rocks,” Smirnov writes in his paper, “relatively quickly cooled shallow intrusions such as mafic dikes and sills represent an attractive alternative target for paleointensity studies.”

    The rocks Smirnov and his team sampled in Australia’s Widgiemooltha dike swarm are the best available, considering the cluster of intrusive rock formations has been eroded, buried and baked over the past two billion years. The dike swarm is important because the Widgiemooltha rocks, collected from 24 different field sites, contain key magnetite grains. After some time in the lab’s magnetometer, the minerals begin to reveal their long-held magnetic secrets.

    Basal Mantle Ocean and Beyond

    Given the rocks’ age and the chaotic nature of the early magnetic field, Smirnov predicted the paleointensity recorded in the magnetite grains would be weak. However, he and his team found the paleointensity readings were relatively strong.

    “This contradicts the models that show a young solid inner core — and right now, that’s a mystery,” Smirnov says. Although, he adds, there is a new theory that is consistent with this data.

    In the basal mantle ocean theory, the boundary between the solid mantle — the bulk of earth’s interior — and the early earth’s core could have been swaddled in a dense layer of partially melted rock. The difference in composition and density could have been enough to jumpstart a stronger magnetic field.

    Delving deeper into the core’s evolution has significance beyond the earth’s interior, too. The magnetic field helps protect life on earth from cosmic radiation. Understanding the ancient geodynamo could also expand our knowledge of earth’s earliest life. Smirnov plans to study that connection — and more exceptionally old rocks — in the next leg of his research.

    See the full article here.

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    Michigan Tech Campus
    Michigan Technological University (http://www.mtu.edu) is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.
    The College of Sciences and Arts (CSA) fills one of the most important roles on the Michigan Tech campus. We play a part in the education of every student who comes through our doors. We take pride in offering essential foundational courses in the natural sciences and mathematics, as well as the social sciences and humanities—courses that underpin every major on campus. With twelve departments, 28 majors, 30-or-so specializations, and more than 50 minors, CSA has carefully developed programs to suit many interests and skill sets. From sound design and audio technology to actuarial science, applied cognitive science and human factors to rhetoric and technical communication, the college offers many unique programs.

  • richardmitnick 1:21 pm on April 6, 2015 Permalink | Reply
    Tags: , Geology, , Sinkholes   

    From livescience: “Why Dangerous Sinkholes Keep Appearing Along the Dead Sea” 


    April 06, 2015
    Tanya Lewis

    Credit: Eli Raz

    For millennia, the salty, mineral-rich waters of the Dead Sea have drawn visitors and health pilgrims to its shores. But in recent years, gaping chasms have been opening up without warning along its banks, posing a threat to such visitors and tourism in general.

    Satellite photograph showing the location of the Dead Sea

    Nestled between Israel and the Palestinian territories to the west, and Jordan to the east, the Dead Sea is famous for is extreme salinity (34 percent salt, almost 10 times as salty as the ocean), and for having the lowest elevation on Earth, at 1,407 feet (429 meters) below sea level.

    But for the past few decades, the sea has been shrinking rapidly, due to the diversion of water from the Jordan River (which feeds the Dead Sea) and mineral mining from its waters in the south. The water’s surface is currently receding by about 3 feet (1 m) per year, according to Hanan Ginat, a geologist and academic chairman of the Dead Sea and Arava Research Center, in Israel.

    For the past few decades, the sea has been receding by about 3 feet (1m) per year, due to the diversion of water from the Jordan River (which feeds the Dead Sea) and mineral mining from its waters in the south. As the briny water recedes, fresh groundwater wells up and dissolves layers of salt, creating large underground cavities, above which sinkholes form. (Image credit: Eli Raz)

    Geologist Eli Raz of Israel’s Dead Sea and Arava Research Center has studied the sinkhole problem in depth. Raz found that many of the craters developed along seismic fault lines in the Jordan Rift Valley. Inside these faults, the dissolved salts are less stable and more susceptible to invading freshwater, which hollows out the gaping holes, Raz’s studies suggest. (Image credit: Eli Raz)

    As the briny water recedes, fresh groundwater wells up and dissolves layers of salt, creating large underground cavities, above which sinkholes form. The holes can open up without warning, Ginat told Live Science. “We’re looking for systems to forecast where they will happen, but it’s very complicated,” he added.

    The main reason for the Dead Sea’s decline is diversion of water from the Jordan River, which used to provide about 450 billion gallons (1.7 billion cubic meters), but now only provides about 20 percent of that, Ginat said. A factory called Dead Sea Works, which pumps out seawater to harvest its salts and minerals, plays a role in the problem, he said.

    Ginat’s colleague at Dead Sea and Arava Research Center, geologist Eli Raz, has studied the sinkhole problem in depth. Raz found that many of the craters developed along seismic fault lines in the Jordan Rift Valley. Inside these faults, the dissolved salts are less stable and more susceptible to invading freshwater, which hollows out the gaping holes, Raz’s studies suggest.

    The sinkholes were first noticed in the 1970s, but have been forming more rapidly in recent years. The holes are dangerous for people who visit or live in the area, and while no one has been killed, the problem should be taken seriously, researchers warn. The sinkholes can reach up to 82 feet (25 m) deep and 131 feet (40 m) in diameter, and nearby holes sometimes join to form giant ones, according to Raz and his colleagues. More than 4,000 sinkholes exist today, mostly on the sea’s western shores, Ginat said.

    However, there may be a way to stave off the Dead Sea’s decline. Authorities have proposed a canal that would run from the Red Sea to the Dead Sea, called the Red Sea-Dead Sea Conduit, which, in addition to providing water to Jordan, Israel and the Palestinian territories, would bring salt water to the Dead Sea and generate electricity to supply its own energy. Israel and Jordan approved the first stage of the project last month, Ginat said.

    “You can’t stop the sinkholes,” Ginat said. But when people plan roads, buildings and other infrastructure, they should take note of the research, “and choose where to put things [based on] the knowledge we have about the sinkholes,” he said.

    Other areas of the world are also home to puzzling sinkholes. For instance, in Siberia, at least seven giant craters have been found since 2014, which scientists believe to be the result of the explosive release of methane gas from melting permafrost. Researchers have called for urgent investigation of the craters out of safety concerns.

    See the full article here.

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  • richardmitnick 9:32 am on January 14, 2015 Permalink | Reply
    Tags: , , Geology   

    From astrobio.net: “Rare Mineral found in a Wisconsin Crater” 

    Astrobiology Magazine

    Astrobiology Magazine

    Jan 14, 2015
    Aaron L. Gronstal

    With support from the NASA Astrobiology Program, Cavosie brought students from the University of Puerto Rico to study outcrops at the Rock Elm meteorite impact structure. Reidite was found in the samples they collected. Credit: Aaron Cavosie

    Scientists have discovered one of the rarest minerals on Earth in a Wisconsin impact crater.

    Aaron Cavosie of the University of Puerto Rico, and member of the NASA Astrobiology Institute Team at the University of Wisconsin, brought students to an impact site in Rock Elm, Wisconsin to collect samples. In those samples, Cavosie and colleagues discovered the mineral reidite, making Rock Elm the fourth site on Earth where the mineral has been found in nature.

    Reidite is created at high pressures and was first identified in the laboratory in the 1960s. The conditions in which reidite forms have been well-constrained by experiments in the lab but, prior to Rock Elm, it was only found naturally in the Chesapeake Bay Impact Structure (Virginia), the Ries Crater (Germany), and the Xiuyan Crater (China).

    The Rock Elm structure is 6.5 kilometers in diameter and was formed during the Middle Ordovician. This means that the reidite found at Rock Elm is at least 450 million years old, making it the oldest preserved reidite yet discovered.

    Another important aspect of the research is that the reidite was found in sandstone – the first time the mineral was spotted in this type of rock. There are many other impact structures that have been formed in sandstone, and its possible that a re-examination of these sites could reveal more reidite.

    “I get the sense that, because reidite had never been found in this kind of rock, if something’s never found there, your not going to go look for it purposefully,” said Cavosie in an interview with Wisconsin Public Radio. “Now that we’ve identified this recorder of even far more extreme impact conditions than what was known previously at Rock Elm, that tool can be applied to many, many other localities to try to recreate the impact conditions and better understand the effects on the surface environments of some of these impacts.”

    Wisconsin Public Radio produced an interview with Aaron Cavosie and Bill Cordua of UW-River Falls, who discovered the Rock Elm disturbance. To listen to the show, visit: http://www.wpr.org/listen/682916

    The initial findings were presented at the 2014 GSA Annual Meeting in Vancouver.

    See the full article here.

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  • richardmitnick 10:00 pm on January 2, 2015 Permalink | Reply
    Tags: , Geology, , ,   

    From U Chicago: “Modern genetics confirm ancient relationship between fins and hands” 

    U Chicago bloc

    University of Chicago

    December 29, 2014
    John Easton

    Paleontologists have documented the evolutionary adaptations necessary for ancient lobe-finned fish to transform pectoral fins used underwater into strong, bony structures, such as those of Tiktaalik roseae. This enabled these emerging tetrapods, animals with limbs, to crawl in shallow water or on land. But evolutionary biologists have wondered why the modern structure called the autopod—comprising wrists and fingers or ankles and toes—has no obvious morphological counterpart in the fins of living fishes.


    In the Dec. 22, 2014, issue of the Proceedings of the National Academy of Sciences, researchers argue previous efforts to connect fin and fingers fell short because they focused on the wrong fish. Instead, they found the rudimentary genetic machinery for mammalian autopod assembly in a non-model fish, the spotted gar, whose genome was recently sequenced.

    “Fossils show that the wrist and digits clearly have an aquatic origin,” said Neil Shubin, the Robert R. Bensley Distinguished Service Professor of Organismal Biology and Anatomy and a leader of the team that discovered Tiktaalik in 2004. “But fins and limbs have different purposes. They have evolved in different directions since they diverged. We wanted to explore, and better understand, their connections by adding genetic and molecular data to what we already know from the fossil record.”

    Initial attempts to confirm the link based on shape comparisons of fin and limb bones were unsuccessful. The autopod differs from most fins. The wrist is composed of a series of small nodular bones, followed by longer thin bones that make up the digits. The bones of living fish fins look much different, with a set of longer bones ending in small circular bones called radials.

    The primary genes that shape the bones, known as the HoxD and HoxA clusters, also differ. The researchers first tested the ability of genetic “switches” that control HoxD and HoxA genes from teleosts—bony, ray-finned fish—to shape the limbs of developing transgenic mice. The fish control switches, however, did not trigger any activity in the autopod.

    Teleost fish—a vast group that includes almost all of the world’s important sport and commercial fish—are widely studied. But researchers began to realize they were not the ideal comparison for studies of how ancient genes were regulated. When they searched for wrist and digit-building genetic switches, they found “a lack of sequence conservation” in teleost species.

    They traced the problem to a radical change in the genetics of teleost fish. More than 300 million years ago, after the fish-like creatures that would become tetrapods split off from other bony fish, a common ancestor of the teleost lineage went through a whole-genome duplication—a phenomenon that has occurred multiple times in evolution.

    By doubling the entire genetic repertoire of teleost fish, this WGD provided them with enormous diversification potential. This may have helped teleosts to adapt, over time, to a variety of environments worldwide. In the process, “the genetic switches that control autopod-building genes were able to drift and shuffle, allowing them to change some of their function, as well as making them harder to identify in comparisons to other animals, such as mice,” said Andrew Gehrke, a graduate student in the Shubin Lab and lead author of the study.

    Not all bony fishes went through the whole genome duplication, however. The spotted gar, a primitive freshwater fish native to North America, split off from teleost fishes before the WGD.

    When the research team compared Hox gene switches from the spotted gar with tetrapods, they found “an unprecedented and previously undescribed level of deep conservation of the vertebrate autopod regulatory apparatus.” This suggests, they note, a high degree of similarity between “distal radials of bony fish and the autopod of tetrapods.”

    They tested this by inserting gar gene switches related to fin development into developing mice. This evoked patterns of activity that were “nearly indistinguishable,” the authors note, from those driven by the mouse genome.

    “Overall,” the researchers conclude, “our results provide regulatory support for an ancient origin of the ‘late’ phase of Hox expression that is responsible for building the autopod.”

    This study was supported by the Brinson Foundation, the National Science Foundation, the Brazilian National Council for Scientific and Technological Development grants, the National Institutes of Health, the Volkswagen Foundation in Germany, the Alexander von Humboldt-Foundation, the Spanish and Andalusian governments, and Proyecto de Excelencia.

    Additional authors include Mayuri Chandran and Tetsuya Nakamura from the University of Chicago; Igor Schneider from the Instituto de Ciencias Biologicas, Universida de Federal do Para, Belem, Brazil; Elisa de la Calle-Mustienes, Juan J. Tena, Carlos Gomez-Marin and José Luis Gómez-Skarmeta from the Centro Andaluz de Biología del Desarrollo, Sevilla, Spain; and Ingo Braasch and John H. Postlethwait from the Institute of Neuroscience, University of Oregon.

    See the full article here.

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    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

  • richardmitnick 8:45 am on December 20, 2014 Permalink | Reply
    Tags: , Geology, ,   

    From Leeds: “Scientists observe the Earth grow a new layer under an Icelandic volcano” 


    University of Leeds

    15 December 2014
    No Writer Credit

    New research into an Icelandic eruption has shed light on how the Earth’s crust forms, according to a paper published today in Nature.


    When the Bárðarbunga volcano, which is buried beneath Iceland’s Vatnajökull ice cap, reawakened in August 2014, scientists had a rare opportunity to monitor how the magma flowed through cracks in the rock away from the volcano.


    The molten rock forms vertical sheet-like features known as dykes, which force the surrounding rock apart.

    Study co-author Professor Andy Hooper from the Centre for Observation and Modelling of Earthquakes, volcanoes and Tectonics (COMET) at the University of Leeds explained: “New crust forms where two tectonic plates are moving away from each other. Mostly this happens beneath the oceans, where it is difficult to observe.

    “However, in Iceland this happens beneath dry land. The events leading to the eruption in August 2014 are the first time that such a rifting episode has occurred there and been observed with modern tools, like GPS and satellite radar.”

    Although it has a long history of eruptions, Bárðarbunga has been increasingly restless since 2005. There was a particularly dynamic period in August and September this year, when more than 22,000 earthquakes were recorded in or around the volcano in just four weeks, due to stress being released as magma forced its way through the rock.

    Using GPS and satellite measurements, the team were able to track the path of the magma for over 45km before it reached a point where it began to erupt, and continues to do so to this day. The rate of dyke propagation was variable and slowed as the magma reached natural barriers, which were overcome by the build-up of pressure, creating a new segment.

    The dyke grows in segments, breaking through from one to the next by the build up of pressure. This explains how focused upwelling of magma under central volcanoes is effectively redistributed over large distances to create new upper crust at divergent plate boundaries, the authors conclude.

    As well as the dyke, the team found ‘ice cauldrons’ – shallow depressions in the ice with circular crevasses, where the base of the glacier had been melted by magma. In addition, radar measurements showed that the ice inside Bárðarbunga’s crater had sunk by 16m, as the volcano floor collapsed.

    COMET PhD student Karsten Spaans from the University of Leeds, a co-author of the study, added: “Using radar measurements from space, we can form an image of caldera movement occurring in one day. Usually we expect to see just noise in the image, but we were amazed to see up to 55cm of subsidence.”

    Like other liquids, magma flows along the path of least resistance, which explains why the dyke at Bárðarbunga changed direction as it progressed. Magma flow was influenced mostly by the lie of the land to start with, but as it moved away from the steeper slopes, the influence of plate movements became more important.

    Summarising the findings, Professor Hooper said: “Our observations of this event showed that the magma injected into the crust took an incredibly roundabout path and proceeded in fits and starts.

    “Initially we were surprised at this complexity, but it turns out we can explain all the twists and turns with a relatively simple model, which considers just the pressure of rock and ice above, and the pull exerted by the plates moving apart.

    The paper Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland is published in Nature on 15 December 2014.

    The research leading to these results has received funding from the European Community’s Seventh Framework Programme under Grant Agreement No. 308377 (Project FUTUREVOLC).

    Read the paper here: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14111.html

    See the full article here.

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    The University of Leeds was founded in 1904, but its origins go back to t­he nineteenth century with the founding of the Leeds School of Medicine in 1831 and then the Yorkshire College of Science in 1874.


  • richardmitnick 7:44 pm on December 18, 2014 Permalink | Reply
    Tags: , Geology, ,   

    From Princeton: “New, tighter timeline confirms ancient volcanism aligned with dinosaurs’ extinction” 

    Princeton University
    Princeton University

    December 18, 2014
    Morgan Kelly, Office of Communications

    A definitive geological timeline shows that a series of massive volcanic explosions 66 million years ago spewed enormous amounts of climate-altering gases into the atmosphere immediately before and during the extinction event that claimed Earth’s non-avian dinosaurs, according to new research from Princeton University.

    A primeval volcanic range in western India known as the Deccan Traps, which were once three times larger than France, began its main phase of eruptions roughly 250,000 years before the Cretaceous-Paleogene, or K-Pg, extinction event, the researchers report in the journal Science. For the next 750,000 years, the volcanoes unleashed more than 1.1 million cubic kilometers (264,000 cubic miles) of lava. The main phase of eruptions comprised about 80-90 percent of the total volume of the Deccan Traps’ lava flow and followed a substantially weaker first phase that began about 1 million years earlier.

    A definitive geological timeline from Princeton University researchers shows that a series of massive eruptions 66 million years ago in a primeval volcanic range in western India known as the Deccan Traps played a role in the extinction event that claimed Earth’s non-avian dinosaurs, and challenges the dominant theory that a meteorite impact was the sole cause of the extinction. Pictured above are the Deccan Traps near Mahabaleshwar, India. (Image courtesy of Gerta Keller, Department of Geosciences)

    The results support the idea that the Deccan Traps played a role in the K-Pg extinction, and challenge the dominant theory that a meteorite impact near present-day Chicxulub, Mexico, was the sole cause of the extinction. The researchers suggest that the Deccan Traps eruptions and the Chicxulub impact need to be considered together when studying and modeling the K-Pg extinction event.

    The Deccan Traps’ part in the K-Pg extinction is consistent with the rest of Earth history, explained lead author Blair Schoene, a Princeton assistant professor of geosciences who specializes in geochronology. Four of the five largest extinction events in the last 500 million years coincided with large volcanic eruptions similar to the Deccan Traps. The K-Pg extinction is the only one that coincides with an asteroid impact, he said.

    “The precedent is there in Earth history that significant climate change and biotic turnover can result from massive volcanic eruptions, and therefore the effect of the Deccan Traps on late-Cretaceous ecosystems should be considered,” Schoene said.

    The researchers suggest that the Deccan Traps eruptions and the meteorite impact near present-day Chicxulub, Mexico, need to be considered together when studying and modeling the Cretaceous-Paleogene extinction event. The main eruption phases for the Deccan Traps (in brown), which were once three times larger than France, began roughly 250,000 years before the extinction event, the researchers found. For the next 750,000 years, the volcanoes unleashed more than 1.1 million cubic kilometers (264,000 cubic miles) of lava, which comprised about 80-90 percent of the total volume of the Deccan Traps’ lava flow. The amount of carbon dioxide and sulfur dioxide the volcanoes poured out would have caused severe ecological fallout. (Illustration by Matilda Luk, Office of Communications)

    The researchers used a precise rock-dating technique to narrow significantly the timeline for the start of the main eruption, which until now was only known to have occurred within 1 million years of the K-Pg extinction, Schoene said. The Princeton group will return to India in January to collect more samples with the purpose of further constraining eruption rates during the 750,000-year volcanic episode.

    Schoene and his co-authors gauged the age of petrified lava flows known as basalt by comparing the existing ratio of uranium to lead given the known rate at which uranium decays over time. The uranium and lead were found in tiny grains — less than a half-millimeter in size — of the mineral zircon. Zircon is widely considered Earth’s best “time capsule” because it contains a lot of uranium and no lead when it crystallizes, but it is scarce in basalts that cooled quickly. The researchers took the unusual approach of looking for zircon in volcanic ash that had been trapped between lava flows, as well as within thick basalt flows where lava would have cooled more slowly.

    The zircon dated from these layers showed that 80-90 percent of the Deccan Traps eruptions occurred in less than a million years, and began very shortly — in geological terms — before the K-Pg extinction. To produce useful models for events such as the K-Pg extinction, scientists want to know the sequence of events to within tens of thousands of years or better, not millions, Schoene said. Margins of millions of years are akin to “a history book with events that have no dates and are not written in chronological order,” he said.

    “We need to know which events happened first and how long before other events, such as when did the Deccan eruptions happen in relation to the K-Pg extinction,” Schoene said. “We’re now able to place a higher resolution timeframe on these eruptions and are one step closer to finding out what the individual effects of the Deccan Traps eruptions were relative to the Chicxulub meteorite.”

    Vincent Courtillot, a geophysicist and professor at Paris University Diderot, said that the paper is important and “provides a significant improvement on the absolute dating of the Deccan Traps.” Courtillot, who is familiar with the Princeton work but had no role in it, led a team that reported in the Journal of Geophysical Research in 2009 that Deccan volcanism occurred in three phases, the second and largest of which coincides with the K-Pg mass extinction. Numerous other papers from his research groups are considered essential to the development of the Deccan Traps hypothesis. (The Princeton researchers also plan to test the three-phases hypothesis, Schoene said. Their data already suggests that the second and third phase might be a single period of eruptions bridged by smaller, “pulse” eruptions, he said.)

    The researchers took an unusual approach to find the mineral needed to construct the timeline for the start of the main Deccan Traps eruption. They compared the existing ratio of uranium to lead in petrified lava flows known as basalts given the known rate at which uranium decays over time. To have enough uranium, however, the researchers needed the mineral zircon, which is scarce in basalts that cooled quickly. Turning to new sources, the researchers found zircon in soil deposits known as red boles (right) that formed in between eruptions and contain volcanic ash (left) that had been trapped between lava flows. They also located zircon within thick basalt flows where lava would have cooled more slowly. (Images courtesy of Blair Schoene, Department of Geosciences)

    The latest work builds on the long-time work by co-author Gerta Keller, a Princeton professor of geosciences, to establish the Deccan Traps as a main cause of the K-Pg extinction. Virginia Tech geologist Dewey McLean first championed the theory 30 years ago and Keller has since become a prominent voice among a large group of scientists who advocate the idea. In 2011, Keller published two papers that together proposed a one-two punch of Deccan volcanism and meteorite strikes that ended life for more than half of Earth’s plants and animals.

    Existing models of the environmental effects of the Deccan eruptions used timelines two to three times longer than what the researchers found, which underestimated the eruptions’ ecological fallout, Keller explained. The amount of carbon dioxide and sulfur dioxide the volcanoes poured out would have produced, respectively, a long-term warming and short-term cooling of the oceans and land, and resulted in highly acidic bodies of water, she said.

    Because these gases dissipate somewhat quickly, however, a timeline of millions of years understates the volcanoes’ environmental repercussions, while a timeframe of hundreds of thousands of years — particularly if the eruptions never truly stopped — provides a stronger correlation. The new work confirms past work by placing the largest Deccan eruptions nearer the K-Pg extinction, but shows a much shorter time frame of just 250,000 years, Keller said.

    “These results have significantly strengthened the case for volcanism as the primary cause for the mass extinction, as well as for the observed rapid climate changes and ocean acidification,” Keller said.

    “The Deccan Traps mass extinction hypothesis has already enjoyed wide acceptance based on our earlier work and a number of studies have independently confirmed the global effects of Deccan volcanism just prior to the mass extinction,” she said. “The current results will go a long way to strengthen the earlier results as well as further challenge the dominance of the Chicxulub hypothesis.”

    Schoene and Keller worked with Kyle Samperton, a doctoral student in Schoene’s research group; Thierry Adatte, a geologist with the University of Lausanne in Switzerland and Keller’s longtime collaborator; Brian Gertsch, who earned his Ph.D. from Princeton in 2010 and is now a research assistant at the University of Lausanne; Syed Khadri, a geology professor at Amravati University in India; and graduate student Michael Eddy and geology professor Samuel Bowring at the Massachusetts Institute of Technology.

    The paper, U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction, was published Dec. 11 in Science. This work was supported by the Princeton Department of Geosciences’ Scott Fund; the National Science Foundation’s Continental Dynamics and Sedimentary Geology and Paleobiology programs; and the NSF Office of International Science and Engineering’s India Program (grant nos. EAR-0447171 and EAR-1026271).

    See the full article here.

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    As a world-renowned research university, Princeton seeks to achieve the highest levels of distinction in the discovery and transmission of knowledge and understanding. At the same time, Princeton is distinctive among research universities in its commitment to undergraduate teaching.

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