Its Tectonics and Its Relationship to East Antarctica
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Mapping Blue-Ice Areas and Crevasses in West Antarctica Using ASTER Images, GPS, and Radar Measurements
CHAPTER 31 Mapping blue-ice areas and crevasses in West Antarctica using ASTER images, GPS, and radar measurements Andre´s Rivera, Fiona Cawkwell, Anja Wendt, and Rodrigo Zamora ABSTRACT from ASTER imagery, with the aim of identifying other landing sites for aircraft, as well as providing Before the satellite era, relatively little was known a detailed map for meteorite seekers. ASTER com- about the interior of the West Antarctic Ice Sheet posite images have also been used to map safe (WAIS). Of special interest are the rock outcrops routes for terrestrial traverses through crevasse associated with blue-ice areas (BIAs), which have zones. High-pass filters enhanced crevasse features, been exploited for logistical purposes as well as but visual analysis proved to be the most reliable being the subject of scientific research. The blue method of identifying all crevasses. ASTER images ice consists of relatively snow-free glacier ice that were superior to microwave imagery for crevasse is undergoing ablation. detection, as the latter can lack sufficient contrast; One of these BIAs is Patriot Hills (80180S, however, only Radarsat imagery provided coverage 81220W) where aircraft with conventional landing of higher latitude regions. Information gleaned gear have been landing for more than 20 years. This from visible imagery can be combined with that is now the main hub supporting large terrestrial of field-based radio-echo sounding and ground- expeditions conducted by Chilean scientists within penetrating radar profiles through the ice to map Antarctica. Kinematic GPS has been used to map internal layers and bedrock topography with the BIAs since 1996, with areas delineated on ASTER objective of enhancing our knowledge of this images since 2001 using both manual and auto- remote region. -
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, -
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. -
Ancient Pre-Glacial Erosion Surfaces Preserved Beneath the West
Edinburgh Research Explorer Ancient pre-glacial erosion surfaces preserved beneath the West Antarctic Ice Sheet Citation for published version: Rose, KC, Ross, N, Jordan, TA, Bingham, RG, Corr, HFJ, Ferraccioli, F, Le Brocq, AM, Rippin, DM & Siegert, MJ 2015, 'Ancient pre-glacial erosion surfaces preserved beneath the West Antarctic Ice Sheet', Earth Surface Dynamcs, vol. 3, pp. 139-152. https://doi.org/10.5194/esurf-3-139-2015 Digital Object Identifier (DOI): 10.5194/esurf-3-139-2015 Link: Link to publication record in Edinburgh Research Explorer Document Version: Publisher's PDF, also known as Version of record Published In: Earth Surface Dynamcs Publisher Rights Statement: The copyright of any article is retained by the author(s). he article as well as associated published material is distributed under the Creative Commons Attribution 3.0 License General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 04. Oct. 2021 Earth Surf. Dynam., 3, 139–152, 2015 www.earth-surf-dynam.net/3/139/2015/ doi:10.5194/esurf-3-139-2015 © Author(s) 2015. -
AUTARKIC a NEWS BULLETIN Published Quarterly by the NEW ZEALAND ANTARCTIC SOCIETY (INC)
AUTARKIC A NEWS BULLETIN published quarterly by the NEW ZEALAND ANTARCTIC SOCIETY (INC) One of Argentina's oldest Antarctic stations. Almirante Brown, which was destroyed by fire on April 12. Situated in picturesque Paradise Bay on the west coast of the Antarctic Peninsula, it was manned first in 1951 by an Argentine Navy detachment, and became a scientific Station in 1955. Pnoto by Colin Monteath w_i -f n M#i R Registered at Post Office Headquarters, VOI. IU, IMO. D Wellington. New Zealand, as a magazine June, 1984 • . SOUTH SANDWICH It SOUTH GEORGIA / SOU1H ORKNEY Is ' \ ^^^----. 6 S i g n y l u K , / ' o O r c a d a s a r g SOUTH AMERICA ,/ Boroa jSyowa%JAPAN \ «rf 7 s a 'Molodezhnaya v/' A S O U T H « 4 i \ T \ U S S R s \ ' E N D E R B Y \ ) > * \ f(f SHETLANO | JV, W/DD Hallev Bay^ DRONNING MAUD LAND / S E A u k v ? C O A T S I d | / LAND T)/ \ Druzhnaya ^General Belgrano arg \-[ • \ z'f/ "i Mawson AlVTARCTIC-\ MAC ROBERTSON LANd\ \ *usi /PENINSUtA'^ [set mjp below) Sobral arg " < X ^ . D a v i s A u s t _ Siple — USA ;. Amundsen-Scon QUEEN MARY LAND ELLSWORTH " q U S A ') LAND ° Vostok ussr / / R o , s \ \ MARIE BYRD fee She/ r*V\ L LAND WILKES LAND Scon A * ROSSI"2*? Vanda n 7 SEA IJ^r 'victoria TERRE . LAND \^„ ADELIE ,> GEORGE V LJ ■Oumout d'Urville iran< 1 L*ningradsfcaya Ar ■ SI USSR,-'' \ ---'•BALIENYU ANTARCTIC PENINSULA 1 Teniente Matienzo arg 2 Esperanza arg 3 Almirante Brown arg 4 Petrel arg 5 Decepcion arg 6 Vicecomodoro Marambio arg * ANTARCTICA 7 Arturo Prat cm.le 8 Bernardo O'Higgms chile 9 Presidents Frei cmile 500 tOOOKiloflinnn 10 Stonington I. -
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. -
1 BC RECORD in a FIRN CORE from WEST ANTARCTICA 1 MARQUETTO ET AL. 2 VOL. 37, APRIL 2020, 1-10 3 4 Refractory Black Carbon Resul
1 BC RECORD IN A FIRN CORE FROM WEST ANTARCTICA 2 MARQUETTO ET AL. 3 VOL. 37, APRIL 2020, 1-10 4 5 Refractory Black Carbon Results and a Method Comparison between Solid-state 6 Cutting and Continuous Melting Sampling of a West Antarctic Snow and Firn Core 7 Luciano MARQUETTO*1,2, Susan KASPARI1, Jefferson Cardia SIMÕES2, and Emil 8 BABIK1 9 1Department of Geological Sciences, Central Washington University, Ellensburg, 10 Washington 98926, USA 11 2Polar and Climatic Center, Federal University of Rio Grande do Sul, Porto Alegre, Rio 12 Grande do Sul, 91509-900, Brazil 13 (Received 12 July 2019; revised 4 September 2019; accepted 24 October 2019) 14 ABSTRACT 15 This work presents the refractory black carbon (rBC) results of a snow and firn core drilled 16 in West Antarctica (79°55'34.6"S, 94°21'13.3"W) during the 2014--15 austral summer, 17 collected by Brazilian researchers as part of the First Brazilian West Antarctic Ice Sheet 18 Traverse. The core was drilled to a depth of 20 m, and we present the results of the first 8 m by 19 comparing two subsampling methods---solid-state cutting and continuous melting---both with 20 discrete sampling. The core was analyzed at the Department of Geological Sciences, Central 21 Washington University (CWU), WA, USA, using a single particle soot photometer (SP2) 22 coupled to a CETAC Marin-5 nebulizer. The continuous melting system was recently * Corresponding author: Luciano MARQUETTO E-mail: [email protected] 1 23 assembled at CWU and these are its first results. -
A 125-Year Record of Climate and Chemistry Variability at the Pine Island Glacier Ice Divide, Antarctica Franciele Schwanck1, Jefferson C
The Cryosphere Discuss., doi:10.5194/tc-2016-242, 2016 Manuscript under review for journal The Cryosphere Published: 7 November 2016 c Author(s) 2016. CC-BY 3.0 License. A 125-year record of climate and chemistry variability at the Pine Island Glacier ice divide, Antarctica Franciele Schwanck1, Jefferson C. Simões1, Michael Handley2, Paul A. Mayewski2, Jeffrey D. Auger2, Ronaldo T. Bernardo1, Francisco E. Aquino1 5 1Centro Polar e Climático, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, 91540-000, Brazil 2Climate Change Institute, University of Maine, Orono, 04469, United States Correspondence to: Franciele Schwanck ([email protected]) Abstract. The Mount Johns (MJ) ice core (79º55'S; 94º23'W) was drilled near the Pine Island Glacier ice divide on the West Antarctic Ice Sheet during the 2008–2009 austral summer, to a depth of 92.26 m. The upper 45 m of the record covers 10 approximately 125 years (1883- 2008) showing marked seasonal variability. Trace element concentrations in 2,137 samples were determined using inductively coupled plasma mass spectrometry. In this study, we reconstruct mineral dust and sea salt aerosol transport and investigate the influence of climate variables on the elemental concentrations to the MJ site. The ice core record reflects changes in emissions as well as atmospheric circulation and transport processes. Our trajectory analysis shows distinct seasonality, with strong westerly transport in the winter months and a secondary northeasterly transport in the 15 summer. During summer months, the trajectories present slow-moving (short) transport and are more locally influenced than in other seasons. Finally, our reanalysis trace element correlations suggest that marine derived trace element concentrations are strongly influenced by sea ice concentration and sea surface temperature anomalies. -
Ancient Pre-Glacial Erosion Surfaces Preserved Beneath the West Antarctic Ice Sheet
Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Earth Surf. Dynam. Discuss., 2, 681–713, 2014 www.earth-surf-dynam-discuss.net/2/681/2014/ doi:10.5194/esurfd-2-681-2014 ESURFD © Author(s) 2014. CC Attribution 3.0 License. 2, 681–713, 2014 This discussion paper is/has been under review for the journal Earth Surface Dynamics (ESurfD). Ancient pre-glacial Please refer to the corresponding final paper in ESurf if available. erosion surfaces preserved beneath Ancient pre-glacial erosion surfaces the West Antarctic Ice Sheet preserved beneath the West Antarctic Ice K. C. Rose et al. Sheet K. C. Rose1, N. Ross2, R. G. Bingham3, H. F. J. Corr4, F. Ferraccioli4, Title Page 4 5 6 7 T. A. Jordan , A. M. Le Brocq , D. M. Rippin , and M. J. Siegert Abstract Introduction 1 Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Conclusions References Bristol, BS8 1SS, UK 2School of Geography, Politics & Sociology, Newcastle University, Tables Figures Newcastle upon Tyne, NE1 7RU, UK 3 School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, UK J I 4British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK 5School of Geography, University of Exeter, Exeter, EX4 4RJ, UK J I 6 Environment Department, University of York, York, YO10 5DD, UK Back Close 7Grantham Institute and Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, UK Full Screen / Esc Printer-friendly Version Interactive Discussion 681 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Received: 16 June 2014 – Accepted: 29 June 2014 – Published: 15 July 2014 Correspondence to: K. -
The Ellsworth Subglacial Mountains and the Early Glacial History of West
1 The Ellsworth Subglacial Highlands: inception and retreat of the West Antarctic Ice 2 Sheet 3 4 Neil Ross1, Tom A. Jordan2, Robert G. Bingham3, Hugh F.J. Corr2, Fausto Ferraccioli2, 5 Anne Le Brocq4, David M. Rippin5, Andrew P. Wright4, and Martin J. Siegert6 6 7 1. School of Geography, Politics and Sociology, Newcastle University, Newcastle upon 8 Tyne, NE1 7RU, UK 9 2. British Antarctic Survey, Cambridge CB3 0ET, UK 10 3. School of Geosciences, University of Aberdeen, Aberdeen AB24 3UF, UK 11 4. School of Geography, University of Exeter, Exeter EX4 4RJ, UK 12 5. Environment Department, University of York, York YO10 5DD, UK 13 6. Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, 14 Bristol BS8 1SS 15 16 ABSTRACT 17 Antarctic subglacial highlands are where the Antarctic ice sheets first developed 18 and the ‘pinning points’ where retreat phases of the marine-based sectors of the 19 ice sheet are impeded. Due to low ice velocities and limited present-day change in 20 the ice sheet interior, West Antarctic subglacial highlands have been overlooked 21 for detailed study. These regions have considerable potential, however, for 22 establishing from where the West Antarctic Ice Sheet (WAIS) originated and grew, 23 and its likely response to warming climates. Here, we characterize the subglacial 24 morphology of the Ellsworth Subglacial Highlands (ESH), West Antarctica, from 25 ground-based and aerogeophysical radio-echo sounding (RES) surveys and the 26 MODIS Mosaic of Antarctica. We document well-preserved classic landforms 27 associated with restricted, dynamic, marine-proximal alpine glaciation, with 28 hanging tributary valleys feeding a significant overdeepened trough (the Ellsworth 29 Trough) cut by valley (tidewater) glaciers. -
Mineral Dust Variability in Central West Antarctica Associated with Ozone Depletion” by M
Atmos. Chem. Phys. Discuss., 12, C6550–C6562, 2012 Atmospheric www.atmos-chem-phys-discuss.net/12/C6550/2012/ Chemistry © Author(s) 2012. This work is distributed under and Physics the Creative Commons Attribute 3.0 License. Discussions Interactive comment on “Mineral dust variability in central West Antarctica associated with ozone depletion” by M. Cataldo et al. M. Cataldo et al. [email protected] Received and published: 4 September 2012 Reviewer’s comment: General Comments of the Reviewer: This is an interesting pa- per that provides a convincing analysis of microparticle concentration decreased by strengthening westerly winds while the size of the deposited particles is increased by stronger storms. Some issues do need attention however, and these are outlined be- low. 1. I would not term the Mount Jones site as being in central West Antarctica. Rather it is in the far eastern part of the West Antarctic Ice Sheet (see Fig. 6) if one excludes the Antarctic Peninsula. Authors : Probably the reviewer made a little confusion in the terminology between C6550 Mount Jones (77o 14’S;142o 04’W) and Mount Johns (79o 55’S;094o 23’W), the sec- ond one the coring site, both located at West Antarctica. Using an acceptable geo- graphical definition for West Antarctica as “ The portion of Antarctica on the west side of the Transantarctic Mountains bounded by the Ross and the Ronne Ice Shelves, the Antarctic Peninsula and the Pacific Ocean sector”, it is safe to say that Mount Johns do belong to the Central portion of West Antarctica (Fig. 1 helps clarify the difference of locations).