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The Enigma of Ophiolites Housing and Registration Now Open VOL. 97 NO. 2 15 JAN 2016 Earth & Space Science News Sounding the Northern Seas What Is the Anthropocene? AGU Awardees and Prize Winners The Enigma of Ophiolites Housing and Registration Now Open Call for Abstracts It’s time to register and reserve your hotel in New Orleans for the 2016 Ocean Sciences Meeting, 21–26 February. Housing Deadline: 28 January 2016 osm.agu.org/2016/ Earth & Space Science News Contents 15 JANUARY 2016 PROJECT UPDATE VOLUME 97, ISSUE 2 13 Sounding the Northern Seas A compilation of underwater terrain provides the most up-to-date mapping of portions of the western Arctic and North Pacific. NEWS 3 Space Dust Delivered Water During Earth’s Formation A new analysis of lava from the deep man- tle indicates that water-soaked dust par- ticles, rather than a barrage of icy comets, asteroids, or other bodies, delivered water to the newly forming Earth. RESEARCH SPOTLIGHT 8 COVER UAE-Oman Mountains Give Clues 26 to Oceanic Crust and Mantle Rocks Slow-Moving Glide Avalanches When oceanic plates meet continental plates, the continental plates Still Pack a Punch usually come out on top. Cases where this is reversed provide valuable The forces exerted by glide avalances can access to oceanic crust and mantle materials. be calculated fairly well. Earth & Space Science News Eos.org // 1 Contents DEPARTMENTS Editor in Chief Barbara T. Richman: AGU, Washington, D. C., USA; eos_ [email protected] Editors Christina M. S. Cohen Wendy S. Gordon Carol A. Stein California Institute Ecologia Consulting, Department of Earth and of Technology, Pasadena, Austin, Texas, USA; Environmental Sciences, Calif., USA; wendy@ecologiaconsulting University of Illinois at cohen@srl .caltech.edu .com Chicago, Chicago, Ill., USA; [email protected] José D. Fuentes David Halpern Department of Meteorology, Jet Propulsion Laboratory, Pennsylvania State Pasadena, Calif., USA; University, University davidhalpern29@gmail Park, Pa., USA; .com [email protected] Editorial Advisory Board M. Lee Allison, Earth and Space John W. Lane, Near-Surface Geophysics Science Informatics Jian Lin, Tectonophysics Mark G. Flanner, Atmospheric Figen Mekik, Paleoceanography Sciences and Paleoclimatology Nicola J. Fox, Space Physics Jerry L. Miller, Ocean Sciences and Aeronomy Michael A. Mischna, Planetary Sciences Steve Frolking, Biogeosciences Thomas H. Painter, Cryosphere Sciences 2836 Edward J. Garnero, Study of the Philip J. Rasch, Global Environmental Earth’s Deep Interior Change Michael N. Gooseff, Hydrology Eric M. Riggs, Education 26–28 Research Spotlight Brian C. Gunter, Geodesy Adrian Tuck, Nonlinear Geophysics Kristine C. Harper, History Sergio Vinciguerra, Mineral Slow-Moving Glide Avalanches Still of Geophysics and Rock Physics Pack a Punch; Improving Indian Susan E. Hough, Natural Hazards Andrew C. Wilcox, Earth and Planetary Summer Monsoon Prediction; Forecast Emily R. Johnson, Volcanology, Surface Processes Geochemistry, and Petrology Earle Williams, Atmospheric Versus Reality: High-Resolution Keith D. Koper, Seismology and Space Electricity Weather Prediction; Convection Robert E. Kopp, Geomagnetism Mary Lou Zoback, Societal Impacts Cycles, Atmosphere, and Ocean Work and Paleomagnetism and Policy Sciences Symbiotically; Aerosols May Play a Staff Big Part in Atmospheric Absorption. Production: Faith A. Ishii, Production Manager; Melissa A. Tribur, Senior Production Specialist; Liz Castenson, Editor’s Assistant; Yael Fitzpatrick, Manager, Design and Branding; Valerie Bassett and Travis Frazier, Electronic Graphics Specialists Editorial: Peter L. Weiss, Manager/Senior News Editor; Mohi Kumar, Scientific 29–32 Positions Available Content Editor; Randy Showstack, Senior News Writer; JoAnna Wendel, Writer; Current job openings in the Earth Shannon Kelleher and Cody Sullivan, Interns and space sciences. Marketing: Angelo Bouselli, Marketing Program Manager; Jamie R. Liu, Manager, Marketing Advertising: Christy Hanson, Manager; Tel: +1-202-777-7536; Email: advertising@ 27 Inside Back Cover: agu.org Postcards from the Field ©2016. American Geophysical Union. All Rights Reserved. Material in this issue may be photocopied by individual scientists for research or classroom use. Permission Seismologists install seismometers in is also granted to use short quotes, figures, and tables for publication in scientific 3–5 News Todtenweis, Germany, to extend the books and journals. For permission for any other uses, contact the AGU Publications coverage of AlpArray. Office. Earth’s Water Came from Space Dust Eos (ISSN 0096-3941) is published semi-monthly, on the 1st and 15th of the month by During Planetary Formation; Laser the American Geophysical Union, 2000 Florida Ave., NW, Washington, DC 20009, Beams Brighten Prospects for Cave USA. Periodical Class postage paid at Washington, D. C., and at additional mailing On the Cover offices. POSTMASTER: Send address changes to Member Service Center, 2000 Science; New Study Reveals How Close-up view of ophiolite rocks from Florida Ave., NW, Washington, DC 20009, USA. Much Groundwater Remains. Wadi Fins, 88 kilometers southwest of Member Service Center: 8:00 a.m.–6:00 p.m. Eastern time; Tel: +1-202-462-6900; Fax: +1-202-328-0566; Tel. orders in U.S.: 1-800-966-2481; Email: [email protected]. Muscat, Oman. The Semail ophiolite, Use AGU’s Geophysical Electronic Manuscript Submissions system to submit a 6–7 Opinion which overlies parts of Oman and the manuscript: http://eos-submit.agu.org. United Arab Emirates, is formed from What Is the Anthropocene? Views expressed in this publication do not necessarily reflect official positions of the oceanic crust and upper mantle rocks American Geophysical Union unless expressly stated. thrust over less dense continental Christine W. McEntee, Executive Director/CEO 18–25 AGU News material. The field of view is about Awardees and Prize Winners Honored 15 centimeters across. Credit: Katie at 2015 AGU Fall Meeting. Pratt/Deep Carbon Observatory. facebook.com/AmericanGeophysicalUnion @AGU_Eos linkedin.com/company/american-geophysical-union youtube.com/user/AGUvideos 2 // Eos 15 January 2016 NEWS tem with as low a D/H ratio as the lava flows. Space Dust Delivered Water However, when they compared their lava sam- ples to meteorites, which are shards of comets During Earth’s Formation or asteroids that landed and were found on Earth, all the meteorites had higher D/H ratios. The mismatch indicates that, most likely, neither the parent comets or asteroids lthough existing theories of where for where that water came from in the solar nor the shards from such bodies are the source Earth’s water comes from assume that system,” said Hallis. Earth’s water resides not of Earth’s water, Hallis told Eos. A ice- rich comets or asteroids hit the just in such familiar locations as oceans, aqui- A study (http://bit.ly/chondrites) published planet after it formed, new research leaves fers, and clouds but also in rock or magma a little more than a year ago in Science also those ideas in the dust. A team of researchers permeated with water molecules and located argued that Earth received its water as it was has found evidence that “Earth has had water deep within the planet. forming, but from really old meteors called since the beginning of its formation,” accord- Easily accessible reservoirs of water near carbonaceous chondrites. However, the ing to planetary scientist Lydia Hallis, who led Earth’s surface, such as the oceans, contain D/H ratio that Hallis and her colleagues the team. deuterium but not at the same concentrations determined for the deep mantle is lower than A recent paper (http://bit.ly/water- origins as when the planet first formed. The concen- that of the chondrites, Hallis said, suggesting - paper) about this evidence, published on trations have changed due to contact with the that something that preceded those 13 November 2015 in the journal Science, points atmosphere, crust, and upper mantle and meteors—i.e., the nebula’s dust—delivered to Earth’s water coming from motes of space exchanges of molecules and atoms between the water. dust with water molecules attached getting those different layers. Although portions of Still, MIT’s Weiss said we know too little incorporated into the planet during its forma- Earth’s mantle do mix, Hallis thinks that the about the D/H ratios of all asteroids and com- tion. area of the deep mantle where the Baffin ets to rule them out as a source of Earth’s Hallis and her colleagues tracked the water Island lava flows came from was an isolated water. “The trouble is, we don’t know the full back to its dusty source by looking at region of the heterogeneous mantle. There- range of meteorites,” he explained. “Our 60- million- year-old lava flows from Baffin fore, those flows didn’t mix with magma from meteorites are just a tiny sample of the enor- Island, Canada, that originated deep within the upper mantle or the crust before erupting, mous diversity of asteroids that are out Earth’s mantle. Within these lava flow sam- which allowed them to preserve their original there.” ples, which cooled into rock after erupting, the D/H ratio, she and her team reported in their In the future, meteorite specialists might team found a low ratio of two isotopes of paper. discover some of the space rocks with hydrogen—specifically, deuterium to ordinary “I think the most important thing is that D/H ratios closer to what Hallis and her col- hydrogen (D/H). The low value strongly indi- they’ve made a good attempt to measure leagues found in the lava flows. In the mean- cates that Earth’s water came from the solar Earth’s original D/H ratio,” said planetary sci- time, their findings “definitely make it less nebula—a swirling disk of dust around the entist Benjamin Weiss of the Massachusetts probable that [asteroids] are the source,” early Sun from which the planets and other Institute of Technology (MIT) in Cambridge, Weiss said. bodies in our solar system formed.
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