Drilling Priorities to Determine the Past Extent of the Antarctic Ice Sheet
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Preservation of Pliocene Age Surfaces Beneath the WAIS: Insights from Emergent Nunataks in the Ohio Range
Preservation of Pliocene age surfaces beneath the WAIS: Insights from emergent nunataks in the Ohio Range Robert P. Ackert Jr., Sujoy Mukhopadhyay Department of Earth and Planetary Science, Harvard University, Cambridge, MA 02138 Harold W. Borns, Aaron E. Putnam Climate Change Institute, University of Maine, Orono, ME, 04469 The granitic bedrock forming the Ohio Range Escarpment and adjacent Bennett and Tuning Nunataks is typically cavernously weathered with pits ranging from a few cm to > 100 cm. The rock remaining between pits often forms delicate structures only several cm thick (tafoni). Cosmogenic 21Ne and 10Be concentrations indicate that the weathered bedrock surfaces are at least 4 million years old with average erosion rates of 15-35 cm /Ma on surfaces between pits. However, exposure ages of erratics on the escarpment 125 m above the present WAIS surface (~1500 m) indicates that the nunataks were buried by the WAIS 10,000 years ago (Ackert et al., 2007). Ice temperatures at these relatively shallow depths would be well below freezing, and the WAIS remained cold-based. Consequently, glacial erosion has been minimal, generally restricted to breakage of only the most delicate weathering structures. Tuning Nunatak is located in an area with higher ice velocities as indicated by crevasses and steeper surface slopes. There, limited quarrying of horizontally jointed bedrock has locally removed up to 1 m of rock and produced a few glacial scratches. Paired 21Ne and 10Be data indicate that the duration of ice cover was limited. Samples of bedrock from three nunataks fall within the zone of simple exposure on 21Ne/10Be vs.10Be plots indicating that unsupported decay of 10Be (half life = 1.5 Myr) was minimal, and no recent burial event exceeded 50, 000 years. -
Flnitflrclid
flNiTflRClID A NEWS BULLETIN published quarterly by the NEW ZEALAND ANTARCTIC SOCIETY (INC) A New Zealand geochemist, Dr W. F. Giggenbach, descends into the inner crater of Mt Erebus on December 23 last year in an unsuccessful attempt to take gas samples. Behind him in the lava lake of the volcano where the temperature is 1000deg Celsius. On his rucksack he carries titanium gas sampling rods. Photo by Colin Monteath VOl. 8, NO. 1 1 . Wellington, New Zealand, as a magazine. o6pt61*11061% I 979I ' . SOUTH SANDWICH Is SOUTH GEORGIA f S O U T H O R K N E Y I s x \ *#****t ■ /o Orcadas arg \ - aanae s» Novolazarevskaya ussr XJ FALKLAND Is /*Signyl.uK ,,'\ V\60-W / -'' \ Syowa japan SOUTH AMERICA /'' /^ y Borga 7 s a "Molodezhnaya A SOUTH , .a /WEDDELL T\USSR SHETLAND DRONNING MAUD LAND ENOERBY \] / Halley Bay^ ununn n mMUU / I s 'SEA uk'v? COATS Ld LAND JJ Druzhnaya ^General Belgrano arg ANTARCTIC %V USSR *» -» /\ ^ Mawson MAC ROBERTSON LANO\ '■ aust /PENINSULA,' "*■ (see map below) /Sohral arg _ ■ = Davis aust /_Siple — USA Amundsen-Scott / queen MARY LAND gMirny [ELLSWORTH u s a / ; t h u s s i " LANO K / ° V o s t o k u s s r / k . MARIE BYRD > LAND WILKES LAND Scott kOSS|nzk SEA I ,*$V /VICTORIA TERRE ' •|Py»/ LAND AOEilE ,y Leningradskaya X' USSR,''' \ 1 3 -------"';BALLENYIs ANTARCTIC PENINSULA ^ v . : 1 Teniente Matienzo arg 2 Esperanza arc 3 Almirante Brown arg 4 Petrel arg 5 Decepcion arg 6 Vicecomodoro Marambio arg ' ANTARCTICA 7 Arturo Prat chile 8 Bernardo O'Higgins chile 1000 Miles 9 Presidents Frei chile * ? 500 1000 Kilometres 10 Stonington I. -
Mem170-Bm.Pdf by Guest on 30 September 2021 452 Index
Index [Italic page numbers indicate major references] acacamite, 437 anticlines, 21, 385 Bathyholcus sp., 135, 136, 137, 150 Acanthagnostus, 108 anticlinorium, 33, 377, 385, 396 Bathyuriscus, 113 accretion, 371 Antispira, 201 manchuriensis, 110 Acmarhachis sp., 133 apatite, 74, 298 Battus sp., 105, 107 Acrotretidae, 252 Aphelaspidinae, 140, 142 Bavaria, 72 actinolite, 13, 298, 299, 335, 336, 339, aphelaspidinids, 130 Beacon Supergroup, 33 346 Aphelaspis sp., 128, 130, 131, 132, Beardmore Glacier, 429 Actinopteris bengalensis, 288 140, 141, 142, 144, 145, 155, 168 beaverite, 440 Africa, southern, 52, 63, 72, 77, 402 Apoptopegma, 206, 207 bedrock, 4, 58, 296, 412, 416, 422, aggregates, 12, 342 craddocki sp., 185, 186, 206, 207, 429, 434, 440 Agnostidae, 104, 105, 109, 116, 122, 208, 210, 244 Bellingsella, 255 131, 132, 133 Appalachian Basin, 71 Bergeronites sp., 112 Angostinae, 130 Appalachian Province, 276 Bicyathus, 281 Agnostoidea, 105 Appalachian metamorphic belt, 343 Billingsella sp., 255, 256, 264 Agnostus, 131 aragonite, 438 Billingsia saratogensis, 201 cyclopyge, 133 Arberiella, 288 Bingham Peak, 86, 129, 185, 190, 194, e genus, 105 Archaeocyathidae, 5, 14, 86, 89, 104, 195, 204, 205, 244 nudus marginata, 105 128, 249, 257, 281 biogeography, 275 parvifrons, 106 Archaeocyathinae, 258 biomicrite, 13, 18 pisiformis, 131, 141 Archaeocyathus, 279, 280, 281, 283 biosparite, 18, 86 pisiformis obesus, 131 Archaeogastropoda, 199 biostratigraphy, 130, 275 punctuosus, 107 Archaeopharetra sp., 281 biotite, 14, 74, 300, 347 repandus, 108 Archaeophialia, -
5 Yr Drilling Tec Plan
Ice Drilling Program LONG RANGE DRILLING TECHNOLOGY PLAN June 30, 2020 Sponsor: National Science Foundation Ice Drilling Program - LONG RANGE DRILLING TECHNOLOGY PLAN - June 30, 2020 Contents 1.0 INTRODUCTION ................................................................................................................................. 4 2.0 ICE AND ROCK DRILLING SYSTEMS AND TECHNOLOGIES ................................................................. 7 Chipmunk Drill ........................................................................................................................................... 8 Hand Augers .............................................................................................................................................. 9 Sidewinder .............................................................................................................................................. 10 Prairie Dog ............................................................................................................................................... 11 Stampfli Drill ............................................................................................................................................ 12 Blue Ice Drill (BID) ................................................................................................................................... 13 Badger-Eclipse Drill ................................................................................................................................. 14 4-Inch -
ICE SHELF MELT RATES and 3D IMAGING by Cameron Scott Lewis Submitted to the Graduate Degree Program in Electrical Engineering An
ICE SHELF MELT RATES AND 3D IMAGING By ©2015 Cameron Scott Lewis Submitted to the graduate degree program in Electrical Engineering and Computer Science and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Doctor of Philosophy. _____________________________________ Chairperson: Prasad Gogineni _____________________________________ Chris Allen _____________________________________ Carl Leuschen _____________________________________ Fernando Rodriguez-Morales _____________________________________ Rick Hale Date Defended: May 8, 2015 This Dissertation Committee for Cameron Lewis certifies that this is the approved version of the following dissertation: Ice Shelf Melt Rates and 3D Imaging _____________________________________ Chairperson: Prasad Gogineni Date Approved: ii Abstract Ice shelves are sensitive indicators of climate change and play a critical role in the stability of ice sheets and oceanic currents. Basal melting of ice shelves plays an important role in both the mass balance of the ice sheet and the global climate system. Airborne- and satellite-based remote sensing systems can perform thickness measurements of ice shelves. Time-separated repeat flight tracks over ice shelves of interest generate data sets that can be used to derive basal melt rates using traditional glaciological techniques. Many previous melt rate studies have relied on surface elevation data gathered by airborne- and satellite-based altimeters. These systems infer melt rates by assuming hydrostatic equilibrium, an assumption that may not be accurate, especially near an ice-shelf’s grounding line. Moderate bandwidth, VHF, ice-penetrating radar has been used to measure ice-shelf profiles with relatively coarse resolution. This study presents the application of an ultra-wide bandwidth (UWB), UHF, ice-penetrating radar to obtain finer resolution data on the ice shelves. -
The Stratigraphy of the Ohio Range, Antarctica
This dissertation has been 65—1200 microfilmed exactly as received LONG, William Ellis, 1930- THE STRATIGRAPHY OF THE OHIO RANGE, ANTARCTICA. The Ohio State University, Ph.D., 1964 G eology University Microfilms, Inc., Ann Arbor, Michigan THE STRATIGRAPHY OF THE OHIO RANGE, ANTARCTICA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By William Ellis Long, B.S., Rl.S. The Ohio State University 1964 Approved by A (Miser Department of Geology PLEASE NOTE: Figure pages are not original copy* ' They tend tc "curl11. Filled in the best way possible. University Microfilms, Inc. Frontispiece. The Ohio Range, Antarctica as seen from the summit of ITIt. Glossopteris. The cliffs of the northern escarpment include Schulthess Buttress and Darling Ridge. The flat area above the cliffs is the Buckeye Table. ACKNOWLEDGMENTS The preparation of this paper is aided by the supervision and advice of Dr. R. P. Goldthwait and Dr. J. M. Schopf. Dr. 5. B. Treves provided petrographic advice and Dir. G. A. Doumani provided information con cerning the invertebrate fossils. Invaluable assistance in the fiBld was provided by Mr. L. L. Lackey, Mr. M. D. Higgins, Mr. J. Ricker, and Mr. C. Skinner. Funds for this study were made available by the Office of Antarctic Programs of the National Science Foundation (NSF grants G-13590 and G-17216). The Ohio State Univer sity Research Foundation and Institute of Polar Studies administered the project (OSURF Projects 1132 and 1258). Logistic support in Antarctica was provided by the United States Navy, especially Air Development Squadron VX6. -
Lower Devonian), Ohio Range, Transantarctic Mountains GEORGIA TECH L=ARY
7 87-670,P 6.000046'24 —tt'Vt.t.tt 4 GEORGIA TECH LIBRAR. Petrology and Sedimentology of the Horlick Formation (Lower Devonian), Ohio Range, Transantarctic Mountains GEORGIA TECH L=ARY NOV 181 'f.ki TS GRY st-Cr ,1M U.S. GEOLOGICAL SURVEY BULLETIN 1780 GEORGIA JECH Libtspir.1 Petrology and Sedimentology of the Horlick Formation (Lower Devonian), Ohio Range, Transantarctic Mountains By LUCY McCARTAN and MARGARET A. BRADSHAW The Horlick Formation is a nearshore marine deposit of fossiliferous sandstone and shale; it is the oldest sedimentary formation in the Ohio Range GEORGIA TECH LIBRARY NOV 1 8 1117 DCUMLiS 9EPOSIT Gift t. ? U.S. GEOLOGICAL SURVEY BULLETIN 1780 DEPARTMENT OF THE INTERIOR DONALD PAUL HODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director UNITED STATES GOVERNMENT PRINTING OFFICE: 1987 For sale by the Books and Open-File Reports Section, U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 Library of Congress Cataloging in Publication Data McCartan, Lucy. Petrology and sedimentology of the Horlick Formation (Lower Devonian), Ohio Range, Transantarctic Mountains. (U.S. Geological Survey bulletin ; 1780) Bibliography: p. Supt. of Docs. no.: I 19.3:1780 1.Sandstone—Antarctic regions—Transantarctic Mountains. 2. Shale—Antarctic regions—Transantarctic Mountains. 3. Sedimentation and deposition—Antarctic regions— Transantarctic Mountains. 4. Geology, Stratigraphic— Devonian. 5. Geology—Antarctic regions—Transantarctic Mountains. I. Bradshaw, Margaret A. II. Title. III. Series. QE75.B9 no. 1780 557.3 s -
We Thank the Reviewers for Their Helpful Feedback, Which Has Improved Our Manuscript. in the Interactive Discussion, We Have Replied to Each Reviewer Directly
Dear Dr. Stroeven (editor), We thank the reviewers for their helpful feedback, which has improved our manuscript. In the Interactive Discussion, we have replied to each Reviewer directly. Below are copies of the Reviewers' comments and our responses as well as the revised manuscript with changes tracked. We would also like to bring to your attention the fact that we have made some changes to the manuscript regarding issues that were not raised by the Review- ers. These changes are described below. In the last paragraph of Section 5.3, we have changed the sentence which read \Circulation of drilling fluid in the RB-1 borehole hydrofractured the basal ice...". The new sentence reads \An unexplained hydrofracture of the basal ice of the RB-1 borehole...". After our initial manuscript submission, we realized that the present-day ground- ing line in our ice-sheet simulation was located upstream of Robin Subglacial Basin in the Weddell Sea sector of the WAIS (compare to Fig. 1). This misfit affects the plots in Fig. 2e-s because, at sites upstream of this area, thinning during interglacial periods is underestimated and thickening during glacial pe- riods is overestimated. To address this, we have taken the following actions. (i) We have added a figure (Fig. 3 in the revised manuscript) showing the misfit between the modeled and the observed present-day ice sheet. This figure shows that the model does reasonably well in most areas, but very poorly in the region of Robin Subglacial Basin. (ii) We added a paragraph to the end of Section 3 explaining this misfit and its consequences. -
REE Tetrad Effect and Sr-Nd Isotope Systematics of A-Type Pirrit Hills Granite from West Antarctica
minerals Article REE Tetrad Effect and Sr-Nd Isotope Systematics of A-Type Pirrit Hills Granite from West Antarctica Hyo Min Lee 1, Seung-Gu Lee 2,* , Hyeoncheol Kim 2, Jong Ik Lee 3 and Mi Jung Lee 3 1 Geoscience Platform Division, Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, Korea; [email protected] 2 Geology Division, Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, Korea; [email protected] 3 Division of Polar Earth-System Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Korea; [email protected] (J.I.L.); [email protected] (M.J.L.) * Correspondence: [email protected]; Tel.: +82-42-868-3376 Abstract: The Pirrit Hills are located in the Ellsworth–Whitmore Mountains of West Antarctica. The Pirrit Hills granite exhibits significant negative Eu anomalies (Eu/Eu* = 0.01~0.25) and a REE tetrad effect indicating intensive magmatic differentiation. Whole-rock Rb-Sr and Sm-Nd geochronologic analysis of the Pirrit Hills granite gave respective ages of 172.8 ± 2.4 Ma with initial 87Sr/86Sr = 0.7065 ± 0.0087 Ma and 169 ± 12 Ma with initial 144Nd/143Nd = 0.512207 ± 0.000017. The isotopic ratio data indicate that the Pirrit Hills granite formed by the remelting of Mesoproterozoic mantle- derived crustal materials. Both chondrite-normalized REE patterns and Sr-Nd isotopic data indicate that the Pirrit Hills granite has geochemical features of chondrite-normalized REE patterns indicating that REE tetrad effects and negative Eu anomalies in the highly fractionated granites were produced Citation: Lee, H.M.; Lee, S.-G.; Kim, from magmatic differentiation under the magmatic-hydrothermal transition system. -
The Transantarctic Mountains These Watercolor Paintings by Dee Molenaar Were Originally Published in 1985 with His Map of the Mcmurdo Sound Area of Antarctica
The Transantarctic Mountains These watercolor paintings by Dee Molenaar were originally published in 1985 with his map of the McMurdo Sound area of Antarctica. We are pleased to republish these paintings with the permission of the artist who owns the copyright. Gunter Faure · Teresa M. Mensing The Transantarctic Mountains Rocks, Ice, Meteorites and Water Gunter Faure Teresa M. Mensing The Ohio State University The Ohio State University School of Earth Sciences School of Earth Sciences and Byrd Polar Research Center and Byrd Polar Research Center 275 Mendenhall Laboratory 1465 Mt. Vernon Ave. 125 South Oval Mall Marion, Ohio 43302 Columbus, Ohio 43210 USA USA [email protected] [email protected] ISBN 978-1-4020-8406-5 e-ISBN 978-90-481-9390-5 DOI 10.1007/978-90-481-9390-5 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2010931610 © Springer Science+Business Media B.V. 2010 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Cover illustration: A tent camp in the Mesa Range of northern Victoria Land at the foot of Mt. Masley. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) We dedicate this book to Lois M. Jones, Eileen McSaveny, Terry Tickhill, and Kay Lindsay who were the first team of women to conduct fieldwork in the Transantarctic Mountains during the 1969/1970 field season. -
Sessions Calendar
Associated Societies GSA has a long tradition of collaborating with a wide range of partners in pursuit of our mutual goals to advance the geosciences, enhance the professional growth of society members, and promote the geosciences in the service of humanity. GSA works with other organizations on many programs and services. AASP - The American Association American Geophysical American Institute American Quaternary American Rock Association for the Palynological Society of Petroleum Union (AGU) of Professional Association Mechanics Association Sciences of Limnology and Geologists (AAPG) Geologists (AIPG) (AMQUA) (ARMA) Oceanography (ASLO) American Water Asociación Geológica Association for Association of Association of Earth Association of Association of Geoscientists Resources Association Argentina (AGA) Women Geoscientists American State Science Editors Environmental & Engineering for International (AWRA) (AWG) Geologists (AASG) (AESE) Geologists (AEG) Development (AGID) Blueprint Earth (BE) The Clay Minerals Colorado Scientifi c Council on Undergraduate Cushman Foundation Environmental & European Association Society (CMS) Society (CSS) Research Geosciences (CF) Engineering Geophysical of Geoscientists & Division (CUR) Society (EEGS) Engineers (EAGE) European Geosciences Geochemical Society Geologica Belgica Geological Association Geological Society of Geological Society of Geological Society of Union (EGU) (GS) (GB) of Canada (GAC) Africa (GSAF) Australia (GSAus) China (GSC) Geological Society of Geological Society of Geologische Geoscience -
Exposure History of West Antarctic Nunataks
Exposure history of West Antarctic nunataks Perry Spector, John Stone, Howard Conway, Dale Winebrenner Department of Earth and Space Science University of Washington Cameron Lewis, John Paden, Prasad Gogineni Center for Remote Sensing of Ice Sheets University of Kansas There is strong evidence that the West Antarctic Ice Sheet has been thinner during the Pleistocene, however the timing, duration, and magnitude of past deglaciations are poorly known. Ice-sheet elevation changes over glacial and interglacial periods can be revealed by cosmogenic-nuclide measurements of bedrock surfaces. Whether ice was thinner during past warm climates can be tested by measuring cosmogenic nuclides in currently subglacial bedrock surfaces, provided that cold-based ice has protected the surfaces from erosion. During 2012-13, we visited three groups of small nunataks in West Antarctica with the intention of locating favorable drilling sites for the recovery of subglacial bedrock to look for evidence of thinner ice in the past. We traveled to the Whitmore Mountains, located near the ice-sheet divide, and the Pirrit and Nash Hills, nunatak groups located in the Weddell sector of West Antarctica at ~1300 and ~1500 m, respectively. At the Pirrit Hills, fresh glacial erratics are evidence of thicker ice during the last ice age and indicate that ice levels were at least ~350 m, but less than ~510 m, above the present level. Despite thicker ice, bedrock at all three sites, extending down to the present ice level, is weathered and exhibits delicate cavernous forms, evidence of prolonged subaerial weathering prior to the last ice age. The preservation of these features, along with the lack of evidence for wet-based glacial erosion, indicates that former ice cover was cold-based and protected the underlying bedrock.