Exploration and Study of Antarctic Subglacial Aquatic Environments (SAE)
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Early Break-Up of the Norwegian Channel Ice Stream During the Last Glacial Maximum
Quaternary Science Reviews 107 (2015) 231e242 Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev Early break-up of the Norwegian Channel Ice Stream during the Last Glacial Maximum * John Inge Svendsen a, , Jason P. Briner b, Jan Mangerud a, Nicolas E. Young c a Department of Earth Science, University of Bergen and Bjerknes Centre for Climate Research, Postbox 7803, N-5020 Bergen, Norway b Department of Geology, University at Buffalo, Buffalo, NY 14260, USA c Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA article info abstract Article history: We present 18 new cosmogenic 10Be exposure ages that constrain the breakup time of the Norwegian Received 11 June 2014 Channel Ice Stream (NCIS) and the initial retreat of the Scandinavian Ice Sheet from the Southwest coast Received in revised form of Norway following the Last Glacial Maximum (LGM). Seven samples from glacially transported erratics 31 October 2014 on the island Utsira, located in the path of the NCIS about 400 km up-flow from the LGM ice front Accepted 3 November 2014 position, yielded an average 10Be age of 22.0 ± 2.0 ka. The distribution of the ages is skewed with the 4 Available online youngest all within the range 20.2e20.8 ka. We place most confidence on this cluster of ages to constrain the timing of ice sheet retreat as we suspect the 3 oldest ages have some inheritance from a previous ice Keywords: Norwegian Channel Ice Stream free period. Three additional ages from the adjacent island Karmøy provided an average age of ± 10 Scandinavian Ice Sheet 20.9 0.7 ka, further supporting the new timing of retreat for the NCIS. -
Ribbed Bedforms in Palaeo-Ice Streams Reveal Shear Margin
https://doi.org/10.5194/tc-2020-336 Preprint. Discussion started: 21 November 2020 c Author(s) 2020. CC BY 4.0 License. Ribbed bedforms in palaeo-ice streams reveal shear margin positions, lobe shutdown and the interaction of meltwater drainage and ice velocity patterns Jean Vérité1, Édouard Ravier1, Olivier Bourgeois2, Stéphane Pochat2, Thomas Lelandais1, Régis 5 Mourgues1, Christopher D. Clark3, Paul Bessin1, David Peigné1, Nigel Atkinson4 1 Laboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, France 2 Laboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes CEDEX 3, France 10 3 Department of Geography, University of Sheffield, Sheffield, UK 4 Alberta Geological Survey, 4th Floor Twin Atria Building, 4999-98 Ave. Edmonton, AB, T6B 2X3, Canada Correspondence to: Jean Vérité ([email protected]) Abstract. Conceptual ice stream landsystems derived from geomorphological and sedimentological observations provide 15 constraints on ice-meltwater-till-bedrock interactions on palaeo-ice stream beds. Within these landsystems, the spatial distribution and formation processes of ribbed bedforms remain unclear. We explore the conditions under which these bedforms develop and their spatial organisation with (i) an experimental model that reproduces the dynamics of ice streams and subglacial landsystems and (ii) an analysis of the distribution of ribbed bedforms on selected examples of paleo-ice stream beds of the Laurentide Ice Sheet. We find that a specific kind of ribbed bedforms can develop subglacially 20 from a flat bed beneath shear margins (i.e., lateral ribbed bedforms) and lobes (i.e., submarginal ribbed bedforms) of ice streams. -
Ice Dynamics and Stability Analysis of the Ice Shelf-Glacial System on the East Antarctic Peninsula Over the Past Half Century: Multi-Sensor
Ice dynamics and stability analysis of the ice shelf-glacial system on the east Antarctic Peninsula over the past half century: multi-sensor observations and numerical modeling A dissertation submitted to the Graduate School of the University of Cincinnati in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Geography & Geographic Information Science of the College of Arts and Sciences by Shujie Wang B.S., GIS, Sun Yat-sen University, China, 2010 M.A., GIS, Sun Yat-sen University, China, 2012 Committee Chair: Hongxing Liu, Ph.D. March 2018 ABSTRACT The flow dynamics and mass balance of the Antarctic Ice Sheet are intricately linked with the global climate change and sea level rise. The dynamics of the ice shelf – glacial systems are particularly important for dominating the mass balance state of the Antarctic Ice Sheet. The flow velocity fields of outlet glaciers and ice streams dictate the ice discharge rate from the interior ice sheet into the ocean system. One of the vital controls that affect the flow dynamics of the outlet glaciers is the stability of the peripheral ice shelves. It is essential to quantitatively analyze the interconnections between ice shelves and outlet glaciers and the destabilization process of ice shelves in the context of climate warming. This research aims to examine the evolving dynamics and the instability development of the Larsen Ice Shelf – glacial system in the east Antarctic Peninsula, which is a dramatically changing area under the influence of rapid regional warming in recent decades. Previous studies regarding the flow dynamics of the Larsen Ice Shelf – glacial system are limited to some specific sites over a few time periods. -
Download Preprint
Ross and Siegert: Lake Ellsworth englacial layers and basal melting 1 1 THIS IS AN EARTHARXIV PREPRINT OF AN ARTICLE SUBMITTED FOR 2 PUBLICATION TO THE ANNALS OF GLACIOLOGY 3 Basal melt over Subglacial Lake Ellsworth and it catchment: insights from englacial layering 1 2 4 Ross, N. , Siegert, M. , 1 5 School of Geography, Politics and Sociology, Newcastle University, Newcastle upon Tyne, 6 UK 2 7 Grantham Institute, Imperial College London, London, UK Annals of Glaciology 61(81) 2019 2 8 Basal melting over Subglacial Lake Ellsworth and its 9 catchment: insights from englacial layering 1 2 10 Neil ROSS, Martin SIEGERT, 1 11 School of Geography, Politics and Sociology, Newcastle University, Newcastle upon Tyne, UK 2 12 Grantham Institute, Imperial College London, London, UK 13 Correspondence: Neil Ross <[email protected]> 14 ABSTRACT. Deep-water ‘stable’ subglacial lakes likely contain microbial life 15 adapted in isolation to extreme environmental conditions. How water is sup- 16 plied into a subglacial lake, and how water outflows, is important for under- 17 standing these conditions. Isochronal radio-echo layers have been used to infer 18 where melting occurs above Lake Vostok and Lake Concordia in East Antarc- 19 tica but have not been used more widely. We examine englacial layers above 20 and around Lake Ellsworth, West Antarctica, to establish where the ice sheet 21 is ‘drawn down’ towards the bed and, thus, experiences melting. Layer draw- 22 down is focused over and around the NW parts of the lake as ice, flowing 23 obliquely to the lake axis, becomes afloat. -
Geochemistry of Subglacial Lake Whillans, West Antarctica: Implications for Microbial Activity
5th International Conference on Polar & Alpine Microbiology, Big Sky, MT, USA, 2013 Geochemistry of subglacial Lake Whillans, West Antarctica: Implications for microbial activity. Mark Skidmore1, Andrew Mitchell2, Carlo Barbante3, Alex Michaud4, Trista Vick-Majors4, John Priscu4 1Earth Sciences, Montana State University, Bozeman, MT, USA, 2Geography and Earth Sciences, Aberystwyth University, Aberystwyth, UK, 3Institute for the Dynamics of Environmental Processes-CNR, University of Venice, Venice, Italy. 4Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA. Subglacial Lake Whillans is located beneath the Whillans Ice Stream in West Antarctica. The lake is situated beneath 800 m of ice and ~ 70 km upstream of the grounding line where Whillans Ice Stream terminates into the Ross Sea. Water and sediment samples were recovered from the lake, using clean access drilling technologies, in January, 2013. Isotopic analysis of the lake waters indicates basal meltwater from the ice sheet as the dominant water source. Geochemical analysis of the lake waters reveal it is freshwater with total dissolved solids concentrations about 1/70th that of sea water. However, mineral weathering is a significant source of solute to the lake water with a contribution also from sea water. Nutrients N and P are present at micromolar concentrations. The sediment porewaters from shallow cores (~ 40 cm depth) of the subglacial lake sediments indicate increasing solute concentration with depth, with up to ~ five times greater solute concentrations than in the lake waters. Collectively the aqueous geochemistry indicates an environment favorable for microbial activity. Thus, microbially-driven mineral weathering appears likely beneath the Whillans Ice Stream, as has been demonstrated in other subglacial systems, including in subglacial sediments of the neighboring Kamb Ice Stream. -
7Th Grade February Break Packet.Pdf
__________________ ___________________ _________________ Read this story. Then answer questions 15 through 21. e narrator, Holling Hoodhood, has a crush on Meryl Lee Kowalski. Holling’s father has been honored earlier in the story by a local business group as the best businessman of 1967. Excerpt from e Wednesday Wars by Gary D. Schmidt 1 e following week the school board met to decide on the model for the new junior high school—which was probably why Mr. Kowalski had been spending all his time muttering “classical, classical, classical.” e meeting was to be at four o’clock in the high school administration building. Mr. Kowalski would present his plan and model, and then my father would present his plan and model, and then the school board would meet in private session to decide whether Kowalski and Associates or Hoodhood and Associates would be the architect for the new junior high school. 2 I know all of this because my father was making me come. It was time I started to learn the business, he said. I needed to see firsthand how competitive bidding worked. I needed to experience architectural presentations. I needed to see architecture as the blood sport that it truly was. 3 e meeting was in the public conference room, and when I got there aer school, the school board members were all sitting at the head table, studying the folders with architectural bids. Mr. Kowalski and my father were sitting at two of the high school desks—which made the whole thing seem a little weirder than it needed to be. -
Antarctic Primer
Antarctic Primer By Nigel Sitwell, Tom Ritchie & Gary Miller By Nigel Sitwell, Tom Ritchie & Gary Miller Designed by: Olivia Young, Aurora Expeditions October 2018 Cover image © I.Tortosa Morgan Suite 12, Level 2 35 Buckingham Street Surry Hills, Sydney NSW 2010, Australia To anyone who goes to the Antarctic, there is a tremendous appeal, an unparalleled combination of grandeur, beauty, vastness, loneliness, and malevolence —all of which sound terribly melodramatic — but which truly convey the actual feeling of Antarctica. Where else in the world are all of these descriptions really true? —Captain T.L.M. Sunter, ‘The Antarctic Century Newsletter ANTARCTIC PRIMER 2018 | 3 CONTENTS I. CONSERVING ANTARCTICA Guidance for Visitors to the Antarctic Antarctica’s Historic Heritage South Georgia Biosecurity II. THE PHYSICAL ENVIRONMENT Antarctica The Southern Ocean The Continent Climate Atmospheric Phenomena The Ozone Hole Climate Change Sea Ice The Antarctic Ice Cap Icebergs A Short Glossary of Ice Terms III. THE BIOLOGICAL ENVIRONMENT Life in Antarctica Adapting to the Cold The Kingdom of Krill IV. THE WILDLIFE Antarctic Squids Antarctic Fishes Antarctic Birds Antarctic Seals Antarctic Whales 4 AURORA EXPEDITIONS | Pioneering expedition travel to the heart of nature. CONTENTS V. EXPLORERS AND SCIENTISTS The Exploration of Antarctica The Antarctic Treaty VI. PLACES YOU MAY VISIT South Shetland Islands Antarctic Peninsula Weddell Sea South Orkney Islands South Georgia The Falkland Islands South Sandwich Islands The Historic Ross Sea Sector Commonwealth Bay VII. FURTHER READING VIII. WILDLIFE CHECKLISTS ANTARCTIC PRIMER 2018 | 5 Adélie penguins in the Antarctic Peninsula I. CONSERVING ANTARCTICA Antarctica is the largest wilderness area on earth, a place that must be preserved in its present, virtually pristine state. -
Rapid Accelerations of Antarctic Peninsula Outlet Glaciers Driven by Surface Melt
This is a repository copy of Rapid accelerations of Antarctic Peninsula outlet glaciers driven by surface melt. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/150042/ Version: Published Version Article: Tuckett, P.A., Ely, J.C. orcid.org/0000-0003-4007-1500, Sole, A.J. et al. (4 more authors) (2019) Rapid accelerations of Antarctic Peninsula outlet glaciers driven by surface melt. Nature Communications, 10. ISSN 2041-1723 https://doi.org/10.1038/s41467-019-12039-2 Reuse This article is distributed under the terms of the Creative Commons Attribution (CC BY) licence. This licence allows you to distribute, remix, tweak, and build upon the work, even commercially, as long as you credit the authors for the original work. More information and the full terms of the licence here: https://creativecommons.org/licenses/ 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. [email protected] https://eprints.whiterose.ac.uk/ ARTICLE https://doi.org/10.1038/s41467-019-12039-2 OPEN Rapid accelerations of Antarctic Peninsula outlet glaciers driven by surface melt Peter A. Tuckett1, Jeremy C. Ely 1*, Andrew J. Sole 1, Stephen J. Livingstone 1, Benjamin J. Davison2, J. Melchior van Wessem3 & Joshua Howard1 Atmospheric warming is increasing surface melting across the Antarctic Peninsula, with unknown impacts upon glacier dynamics at the ice-bed interface. Using high-resolution 1234567890():,; satellite-derived ice velocity data, optical satellite imagery and regional climate modelling, we show that drainage of surface meltwater to the bed of outlet glaciers on the Antarctic Peninsula occurs and triggers rapid ice flow accelerations (up to 100% greater than the annual mean). -
Perchlorate and Chlorate Biogeochemistry in Ice-Covered Lakes of the Mcmurdo Dry Valleys, Antarctica
Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 98 (2012) 19–30 www.elsevier.com/locate/gca Perchlorate and chlorate biogeochemistry in ice-covered lakes of the McMurdo Dry Valleys, Antarctica W. Andrew Jackson a,⇑, Alfonso F. Davila b,c, Nubia Estrada a, W. Berry Lyons d, John D. Coates e, John C. Priscu f a Department of Civil and Environmental Engineering, Texas Tech University, Lubbock, TX 79409, USA b NASA Ames Research Center, Moffett Field, CA 95136, USA c SETI Institute, 189 Bernardo Ave., Suite 100, Mountain View, CA 94043-5203, USA d Byrd Polar Research Center, The Ohio State University, Columbus, OH 43210, USA e Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA f Department of Land Resources & Environmental Sciences, Montana State University, Bozeman, MT 59717, USA Received 15 February 2012; accepted in revised form 5 September 2012; available online 19 September 2012 Abstract À À We measured chlorate (ClO3 ) and perchlorate (ClO4 ) concentrations in ice covered lakes of the McMurdo Dry Valleys À À (MDVs) of Antarctica, to evaluate their role in the ecology and geochemical evolution of the lakes. ClO3 and ClO4 are À À present throughout the MDV Lakes, streams, and other surface water bodies. ClO3 and ClO4 originate in the atmosphere and are transported to the lakes by surface inflow of glacier melt that has been differentially impacted by interaction with soils À À and aeolian matter. Concentrations of ClO3 and ClO4 in the lakes and between lakes vary based on both total evaporative concentration, as well as biological activity within each lake. -
A Significant Acceleration of Ice Volume Discharge Preceded a Major Retreat of a West Antarctic Paleo–Ice Stream
https://doi.org/10.1130/G46916.1 Manuscript received 26 August 2019 Revised manuscript received 23 November 2019 Manuscript accepted 26 November 2019 © 2019 Geological Society of America. For permission to copy, contact [email protected]. A signifcant acceleration of ice volume discharge preceded a major retreat of a West Antarctic paleo–ice stream Philip J. Bart1 and Slawek Tulaczyk2 1 Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA 2 Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, California 95064, USA ABSTRACT SEDIMENT AND ICE DISCHARGE For the period between 14.7 and 11.5 cal. (calibrated) kyr B.P, the sediment fux of Bind- FROM THE PALEO–BINDSCHADLER schadler Ice Stream (BIS; West Antarctica) averaged 1.7 × 108 m3 a−1. This implies that BIS ICE STREAM velocity averaged 500 ± 120 m a−1. At a fner resolution, the data suggest two stages of ice Radiocarbon ages from benthic foramin- stream fow. During the frst 2400 ± 400 years of a grounding-zone stillstand, ice stream fow ifera (Bart et al., 2018) (Table 1) indicate that averaged 200 ± 90 m a−1. Following ice-shelf breakup at 12.3 ± 0.2 cal. kyr B.P., fow acceler- the paleo-BIS grounding line had retreated ated to 1350 ± 580 m a−1. The estimated ice volume discharge after breakup exceeds the bal- 70 km from its maximum (LGM) position by ance velocity by a factor of two and implies ice mass imbalance of −40 Gt a−1 just before the 14.7 ± 0.4 cal. -
The Antarctic Treaty
The Antarctic Treaty Measures adopted at the Thirty-ninth Consultative Meeting held at Santiago, Chile 23 May – 1 June 2016 Presented to Parliament by the Secretary of State for Foreign and Commonwealth Affairs by Command of Her Majesty November 2017 Cm 9542 © Crown copyright 2017 This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned. This publication is available at www.gov.uk/government/publications Any enquiries regarding this publication should be sent to us at Treaty Section, Foreign and Commonwealth Office, King Charles Street, London, SW1A 2AH ISBN 978-1-5286-0126-9 CCS1117441642 11/17 Printed on paper containing 75% recycled fibre content minimum Printed in the UK by the APS Group on behalf of the Controller of Her Majestyʼs Stationery Office MEASURES ADOPTED AT THE THIRTY-NINTH ANTARCTIC TREATY CONSULTATIVE MEETING Santiago, Chile 23 May – 1 June 2016 The Measures1 adopted at the Thirty-ninth Antarctic Treaty Consultative Meeting are reproduced below from the Final Report of the Meeting. In accordance with Article IX, paragraph 4, of the Antarctic Treaty, the Measures adopted at Consultative Meetings become effective upon approval by all Contracting Parties whose representatives were entitled to participate in the meeting at which they were adopted (i.e. all the Consultative Parties). The full text of the Final Report of the Meeting, including the Decisions and Resolutions adopted at that Meeting and colour copies of the maps found in this command paper, is available on the website of the Antarctic Treaty Secretariat at www.ats.aq/documents. -
The U-Pb Detrital Zircon Signature of West Antarctic Ice Stream Tills in The
Antarctic Science 26(6), 687–697 (2014) © Antarctic Science Ltd 2014. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. doi:10.1017/S0954102014000315 The U-Pb detrital zircon signature of West Antarctic ice stream tills in the Ross embayment, with implications for Last Glacial Maximum ice flow reconstructions KATHY J. LICHT, ANDREA J. HENNESSY and BETHANY M. WELKE Indiana University-Purdue University Indianapolis, Department of Earth Sciences, 723 West Michigan Street, Indianapolis, IN 46202, USA [email protected] Abstract: Glacial till samples collected from beneath the Bindschadler and Kamb ice streams have a distinct U-Pb detrital zircon signature that allows them to be identified in Ross Sea tills. These two sites contain a population of Cretaceous grains 100–110 Ma that have not been found in East Antarctic tills. Additionally, Bindschadler and Kamb ice streams have an abundance of Ordovician grains (450–475 Ma) and a cluster of ages 330–370 Ma, which are much less common in the remainder of the sample set. These tracers of a West Antarctic provenance are also found east of 180° longitude in eastern Ross Sea tills deposited during the last glacial maximum (LGM). Whillans Ice Stream (WIS), considered part of the West Antarctic Ice Sheet but partially originating in East Antarctica, lacks these distinctive signatures. Its U-Pb zircon age population is dominated by grains 500–550 Ma indicating derivation from Granite Harbour Intrusive rocks common along the Transantarctic Mountains, making it indistinguishable from East Antarctic tills.