The Gangdese Retroarc Thrust Belt Revealed
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Climate History Spanning the Past 17,000 Years at the Bottom of a South Island Lake
VOL. 98 NO. 10 OCT 2017 Lakebed Cores Record Shifting Winds Cell Phone App Aids Irrigation Earth & Space Science News Red/Blue and Peer Review A New Clue about CO2 UPTAKE Act Now to Save on Registration and Housing Early Registration Deadline: 3 November 2017, 11:59 P.M. ET Housing Deadline: 15 November 2017, 11:59 P.M. ET fallmeeting.agu.org Earth & Space Science News Contents OCTOBER 2017 PROJECT UPDATE VOLUME 98, ISSUE 10 12 Shifting Winds Write Their History on a New Zealand Lake Bed A team of scientists finds a year-by-year record of climate history spanning the past 17,000 years at the bottom of a South Island lake. PROJECT UPDATE 18 Growing More with Less Using Cell Phones and Satellite Data Researchers from the University of Washington and Pakistan are using 21st-century technology to revive farming as a profitable profession in the Indus 24 Valley. OPINION COVER Red/Blue Assessing a New Clue 10 and Peer Review Healthy skepticism has long formed the to How Much Carbon Plants Take Up foundation of the scientific peer review Current climate models disagree on how much carbon dioxide land ecosystems take up process. Will anything substantively new be for photosynthesis. Tracking the stronger carbonyl sulfide signal could help. gleaned from a red team/blue team exercise? 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., José D. -
1 Rapid Early Miocene Exhumation of the Ladakh Batholith, Western
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Strathclyde Institutional Repository Rapid Early Miocene exhumation of the Ladakh Batholith, western Himalaya. Linda A. Kirstein 1, Hugh Sinclair 1, Finlay M. Stuart 2, Katherine Dobson 2, 3 1School of GeoSciences, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JW, U.K. 2Isotope Geosciences Unit, SUERC, Rankine Avenue, East Kilbride, Glasgow, G75 0QF, U.K. 3Department of Geographical and Earth Sciences, University of Glasgow, Lilybank Gardens, Glasgow, G12 8QQ UK. ABSTRACT Zircon and apatite (U-Th)/He, and apatite fission track age data record a major rapid cooling event of the Ladakh Batholith of northwest India at c. 22 Ma. Combining the thermochronometric data with structural evidence it is proposed that exhumation was due to south-directed overthrusting of the Batholith. This thrust is potentially an extension of the Gangdese Thrust which accommodates underthrusting of the Gangdese Batholith in southern Tibet. The rapid exhumation recorded in Ladakh is contemporaneous with exhumation of the High Himalaya. This focused denudation and structural shortening north of the Indus Suture Zone in early Miocene times implies that the actively deforming and eroding Himalayan thrust wedge extended further north than channel flow models currently predict. 1 INTRODUCTION The Himalayan mountain chain is bordered to the north by a line of arc-derived batholiths known as the Trans-Himalayan Plutonic Belt that stretch 2500 km from Afghanistan in the west to Bhutan (Honneger et al., 1982). Prior to collision at approximately 55 Ma, there was extensive oceanic subduction northward beneath the Plutonic belt now preserved as slivers of ophiolite in the Zanskar Range (Searle et al., 1997; Makovsky et al., 1999). -
Late Paleozoic and Mesozoic Evolution of the Lhasa Terrane in the Xainza MARK Area of Southern Tibet
Tectonophysics 721 (2017) 415–434 Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto Late Paleozoic and Mesozoic evolution of the Lhasa Terrane in the Xainza MARK area of southern Tibet ⁎ Suoya Fana,b, , Lin Dinga, Michael A. Murphyb, Wei Yaoa, An Yinc a Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China b Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77204, USA c Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095-1567, USA ARTICLE INFO ABSTRACT Keywords: Models for the Mesozoic growth of the Tibetan plateau describe closure of the Bangong Ocean resulting in Lhasa terrane accretion of the Lhasa terrane to the Qiangtang terrane along the Bangong-Nuijiang suture zone (BNSZ). Shortening However, a more complex history is suggested by studies of ophiolitic melanges south of the BNSZ “within” the Foreland basin Lhasa terrane. One such mélange belt is the Shiquanhe-Namu Co mélange zone (SNMZ) that is coincident with Suture zone the Geren Co-Namu Co thrust (GNT). To better understand the structure, age, and provenance of rocks exposed Provenance along the SNMZ we conducted geologic mapping, sandstone petrography, and U-Pb zircon geochronology of Geochronology rocks straddling the SNMZ. The GNT is north-directed and places Paleozoic strata against the Yongzhu ophiolite and Cretaceous strata along strike. A gabbro in the Yongzhu ophiolite yielded a U-Pb zircon age of 153 Ma. Detrital zircon age data from Permian rocks in the hanging wall suggests that the Lhasa terrane has affinity with the Himalaya and Qiangtang, rather than northwest Australia. -
People, Land & Water
Thinking Globally but Guiding the Local Message for the 1906 Centennial Photo courtesy California Historical Society By Stephanie Hanna earthquake will occur in this region and Macelwane Award for signifi cant contri- what additional risk and damage might butions to the geophysical sciences by a s the pace of events builds occur from a similar magnitude earth- young scientist of outstanding ability. toward a crescendo on quake that begins either south or north When asked what draws her from April 18, 2006, for the of this area and “steps over” to devastate research to her dedication to public Centennial of the Great San areas further along the San Andreas outreach on earthquake hazards and Francisco Earthquake, Mary Fault. preparedness, Zoback said, “I think it’s ALou Zoback’s work week extends into the Early in her career with USGS, Zoback my personality. When I see problems, I weekend and often well into the evening. headed the International Lithosphere want them to be fi xed. The study of geol- She is currently regional coordinator for Program’s World Stress Map Project. A ogy and geophysics shows us that earth- the USGS Earthquake Hazards Program team of 40 scientists from 30 countries quakes are not random events and that in Northern California and chairs the focused on compiling, standardizing they will happen again where they have steering committee of federal, state, local data collection and interpreting geologic happened before, so we must help society and private partners making up the 1906 and geophysical data on the modern-day be prepared.” Centennial Alliance. -
People, Land & Water
At 5:12 in the morning on April 18, 1906, the Bay Area was literally thrown from bed by what was dubbed “The Great San Francisco Earthquake” and has become the most famous earthquake in U.S. history. 4 PEOPLE, LAND & WATER ★ April 2006 The Great San Francisco Earthquake A Moment of Magnitude for By David Hebert n December 1904, a University of California at Berkeley geology professor named Andrew Lawson wrote the following in the university’s America and for Science newspaper: “History and records show that earthquakes in this locality have never been of Ia violent nature, as so far as I can judge from the na- ture of recent disturbances and from accounts of past occurrences there is not occasion for alarm at present.” Less than two years later, he might have considered a retraction. At 5:12 in the morning on April 18, 1906, the Bay Area was literally thrown from bed by what was dubbed “The Great San Francisco Earthquake” and has become the most famous earthquake in U.S. history. Starting under the Pacifi c, just off the coast of the San Francisco peninsula, the magnitude-7.9 temblor grew until it had caused shaking and damage along nearly 300 miles of the then-unknown San Andreas Fault in Northern California. Strong shaking lasted for nearly a minute, and in some places along the fault, the earth moved more than 25 feet. For those who were there, it was surely a singular experience. “My sensations … were of being on ship in a gale pounding against the rocks, being thrown this way and that, then up in the air, and dropped with a sickening thud that took away my breath,” said Melissa Stewart McKee Carnahan in her 1908 book documenting her personal experiences of the earthquake. -
Timing of Late Cenozoic Volcanic and Tectonic Events Along the Western Margin of the North American Plate
Timing of late Cenozoic volcanic and tectonic events along the western margin of the North American plate WARREN BARRASH Geoscience Research Consultants; and Department of Geology, University of Idaho, Moscow, Idaho 83843 RAMESH VENKATAK.RISHNAN* Geophotography and Remote Sensing Center, University of Idaho, Moscow, Idaho 83843 ABSTRACT TECTONIC SETTING PRIOR TO 16 + 1 M.Y. B.P. A number of well- to relatively well-dated significant volcanic Subduction of the Farallon plate dominated the volcanic and and tectonic events along the western margin of the North Ameri- tectonic setting of western North America during early to middle can plate began, ended, or increased intensity at 16 ± I m.y. B.P., Tertiary time. Subduction-related volcanism migrated over much of 10 ± 2 m.y. B.P., and 5 ± 1 m.y. B.P. Continental events at 16 ± 1 the western United States, including areas as far inland as western m.y. B.P. were related to the upwelling of an elongated mantle Montana, Wyoming, and Colorado. A shallow dip to the subduct- diapir, which created a widespread thermal disturbance east of the ing plate appears to be required by the far inland position of arc subducting Farallon plate. Oceanic events at 16 ± 1 m.y. B.P. were volcanism (Lipman and others, 1972; Coney and Reynolds, 1977). largely related to the approach of the East Pacific Rise toward the Contact of the East Pacific Rise with the North American plate North American plate. Continental and oceanic events at 10 ±2 margin at about 30 m.y. B.P. initiated a northward and southward m.y. -
Microcontinent Subduction and S-Type Volcanism Prior to India–Asia Collision
www.nature.com/scientificreports OPEN Microcontinent subduction and S‑type volcanism prior to India–Asia collision Zongyao Yang1,2, Juxing Tang1,2*, M. Santosh3,4, Xiaoyan Zhao1*, Xinghai Lang5, Ying Wang1, Shuai Ding5 & Fengqin Ran5 Continental crust has long been considered too buoyant to be subducted beneath another continent, although geophysical evidence in collision zones predict continental crust subduction. This is particularly signifcant where upper continental crust is detached allowing the lower continental crust to subduct, albeit the mechanism of such subduction and recycling of the upper continental crust remain poorly understood. Here, we investigate Paleocene S‑type magmatic and volcanic rocks from the Linzizong volcanic succession in the southern Lhasa block of Tibet. These rocks exhibit highly enriched 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb together with depleted 143Nd/144Nd isotope ratios. The geochemical and isotopic features of these rocks are consistent with those of modern upper continental crust. We conclude that these Paleocene S‑type volcanic and magmatic rocks originated from the melting of the upper continental crust from microcontinent subduction during the late stage of India–Asia convergence. Te amalgamation of the Indian and Asian lithospheric plates and the construction of the Himalayan–Tibetan orogens mark one of the most prominent collisional events on the globe 1,2. Te rise of the Qinghai–Tibet Plateau as the highest plateau in the world with an average elevation of around 3000 m is a remarkable outcome of the India–Asia collision along the Indus–Yarlung suture zone (IYSZ)3 (Fig. 1). Te Linzizong volcanic succession (LVS) and the coeval intrusive rocks in southern Tibet, which cover more than 50% of the Gangdese Belt extend- ing E–W for more than 1200 km (Fig. -
Celebrating 125 Years of the U.S. Geological Survey
Celebrating 125 Years of the U.S. Geological Survey Circular 1274 U.S. Department of the Interior U.S. Geological Survey Celebrating 125 Years of the U.S. Geological Survey Compiled by Kathleen K. Gohn Circular 1274 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director U.S. Geological Survey, Reston, Virginia: 2004 Free on application to U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Gohn, Kathleen K., comp., 2004, Celebrating 125 years of the U.S. Geological Survey : U.S. Geological Survey Circular 1274, 56 p. Library of Congress Cataloging-in-Publication Data 2001051109 ISBN 0-607-86197-5 iii Message from the Today, the USGS continues respond as new environmental to map, measure, and monitor challenges and concerns emerge Director our land and its resources and and to seize new enhancements to conduct research that builds to information technology that In the 125 years since its fundamental knowledge about make producing and present- creation, the U.S. Geological the Earth, its resources, and its ing our science both easier and Survey (USGS) has provided processes, contributing relevant faster. -
Zircon U–Pb Geochronology and Hf Isotopic Constraints on Petrogenesis of the Gangdese Batholith, Southern Tibet
Chemical Geology 262 (2009) 229–245 Contents lists available at ScienceDirect Chemical Geology journal homepage: www.elsevier.com/locate/chemgeo Zircon U–Pb geochronology and Hf isotopic constraints on petrogenesis of the Gangdese batholith, southern Tibet Wei-Qiang Ji a, Fu-Yuan Wu a,⁎, Sun-Lin Chung b, Jin-Xiang Li a, Chuan-Zhou Liu a a State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China b Department of Geosciences, National Taiwan University, Taipei 106, Taiwan article info abstract Article history: During the Mesozoic–Cenozoic, northward Neotethyan subduction and subsequent India–Asia collision gave Received 16 June 2008 rise to the extensive Transhimalayan magmatism that stretches from Burma and western Yunnan through Received in revised form 16 January 2009 southern Tibet to the Ladakh and Kohistan complexes. To understand the age distribution and petrogenesis of Accepted 20 January 2009 the Gangdese batholith, the largest intrusive exposure along the Transhimalayan magmatic belt, fifty granitic Editor: R.L. Rudnick samples were selected for in situ zircon U–Pb and Hf isotopic analyses. The U–Pb data suggest four discrete stages of magmatic activity, i.e., ~205–152, ~ 109–80, ~65–41 and ~33–13 Ma, respectively, with the 65– Keywords: 41 Ma stage being the most prominent. The Hf isotopic data indicate that the Gangdese batholith is U–Pb age overwhelmed by positive εHf(t) values, which are comparable to those of the Kohistan–Ladakh batholiths in Hf isotope the west but differ markedly from those of the Chayu–Burma batholiths in the east. -
Age and Anatomy of the Gongga Shan Batholith, Eastern Tibetan Plateau, and Its Relationship to the Active Xianshui-He Fault
This is a repository copy of Age and Anatomy of the Gongga Shan batholith, eastern Tibetan Plateau, and its relationship to the active Xianshui-he fault. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/101886/ Version: Accepted Version Article: Searle, MP, Roberts, NMW, Chung, S-L et al. (8 more authors) (2016) Age and Anatomy of the Gongga Shan batholith, eastern Tibetan Plateau, and its relationship to the active Xianshui-he fault. Geosphere, 12 (3). pp. 948-970. ISSN 1553-040X https://doi.org/10.1130/GES01244.1 © 2016, Geological Society of America. This is an author produced version of a paper published in Geosphere. Uploaded in accordance with the publisher's self-archiving policy. Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. -
The Dickin-Stone-Ian Artic and Alpine Climate Change Experience (AACCRE) Trips 2016-2018 by Ben Edwards
Earth Sciences Newsletter 2018 The Dickin-stone-ian Artic and Alpine Climate Change Experience (AACCRE) Trips 2016-2018 by Ben Edwards Thanks to continued very generous support from John and Susan Pohl, we are growing our Arctic and Alpine Climate Change Experience program. In Summer 2016, a group of 6 Dickinsonians (Billy Dougherty ’18, Ivy Gil- bert’18, Karuna Sah’19, John and Susan Pohl, Ben Edwards) expeditioned to Pond Inlet, at the northern edge of Baffin Island, and trekked out onto the frozen waters of Eclipse Sound to camp on still frozen sea ice for a week. The flight up became a short course on glaciers as we flew over vast expanses of retreating ice on the northeastern mountains of Baffin Island. Once we got our gear packed in qamutiiks (wooden sleds about 10 feet long), we were hauled about 4 hours down the ice to the eastern edge of Eclipse Sound, where it enters northwestern Baffin Bay. While camped on the sea ice we explored the ice floe edge where we saw and heard narwhals and seals, lots of birds, and even a polar bear (we had an Inuit guide with bear protection 24/7!). To learn more about the structure of the spring sea ice, we augered holes in several locations and found ice as thick as 1.4 m (this was comforting!) and as thin as 40 cm (somewhat less comforting…). We also recorded pH and conductivity measurements of water within the sea ice, and found that it had components from surface melting (relatively ‘fresh’ water, lower pH and EC) as well as sea water within the ice layers. -
Exhumation History of the Gangdese Batholith, Southern Tibetan Plateau
Exhumation History of the Gangdese Batholith, Southern Tibetan Plateau: Evidence from Apatite and Zircon (U-Th)/He Thermochronology Author(s): Jingen Dai, Chengshan Wang, Jeremy Hourigan, Zhijun Li, and Guangsheng Zhuang Source: The Journal of Geology, Vol. 121, No. 2 (March 2013), pp. 155-172 Published by: The University of Chicago Press Stable URL: http://www.jstor.org/stable/10.1086/669250 . Accessed: 09/09/2013 01:52 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to The Journal of Geology. http://www.jstor.org This content downloaded from 132.239.1.230 on Mon, 9 Sep 2013 01:53:00 AM All use subject to JSTOR Terms and Conditions Exhumation History of the Gangdese Batholith, Southern Tibetan Plateau: Evidence from Apatite and Zircon (U-Th)/He Thermochronology Jingen Dai,1,* Chengshan Wang,1 Jeremy Hourigan,2 Zhijun Li,3 and Guangsheng Zhuang4 1. State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, Research Center for Tibetan Plateau Geology, China University of Geosciences (Beijing), Beijing 100083, China; 2.