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T Antarctic Ce Sheet Itiative
race Publication 3115, Vol. 1 t Antarctic ce Sheet itiative :_,.me.-1: Science and ;mentation Plan iv-_J_ E -- --__o • E _-- rz " _ • _ _v_-- . "2-. .... E _ ____ __ _k - -- - ...... --rr r_--_.-- .... m-- _ £3._= --- - • ,r- ..... _ k • -- ..... __= ---- = ............ --_ m -- -- ..... Z Im .... r .... _,... ___ "--. 11 1"1 I' I i ¸ NASA Conference Publication 3115, Vol. 1 West Antarctic Ice Sheet Initiative Volume 1: Science and Implementation Plan Edited by Robert A. Bindschadler NASA Goddard Space Flight Center Greenbelt, Maryland Proceedings of a workshop cosponsored by the National Aeronautics and Space Administration, Washington, D.C., and the National Science Foundation, Washington, D.C., and held at Goddard Space Flight Center Greenbelt, Maryland October 16-18, 1990 IXl/_/X National Aeronautics and Space Administration Office of Management Scientific and Technical Information Division 1991 CONTENTS Page Preface v Workshop Participants vi Acknowledgements vii Map viii 1. Executive Summary 1 2. Climatic Importance of Ice Sheets 4 3. Marine Ice Sheet Instability 5 4. The West Antarctic Ice Sheet Initiative 6 4.1 Goal and Objectives 6 4.2 A Multidisciplinary Project 7 4.3 Scientific Focus: A Single Goal 7 4.4 Geographic Focus: West Antarctica 7 4.5 Duration: A Phased Approach 8 5. Science Plan 10 5.1 Glaciology 10 5.1.1 Ice Dynamics 10 5.1.2 Ice Cores 16 5.2 Meteorology 19 5.3 Oceanography 23 5.4 Geology and Geophysics 27 5.4.1 Terrestrial Geology 27 5.4.2 Marine Geology and Geophysics 28 5.4.3 Subglacial Geology and Geophysics 30 6. -
The Ross Sea Dipole - Temperature, Snow Accumulation and Sea Ice Variability in the Ross Sea Region, Antarctica, Over the Past 2,700 Years
Clim. Past Discuss., https://doi.org/10.5194/cp-2017-95 Manuscript under review for journal Clim. Past Discussion started: 1 August 2017 c Author(s) 2017. CC BY 4.0 License. The Ross Sea Dipole - Temperature, Snow Accumulation and Sea Ice Variability in the Ross Sea Region, Antarctica, over the Past 2,700 Years 5 RICE Community (Nancy A.N. Bertler1,2, Howard Conway3, Dorthe Dahl-Jensen4, Daniel B. Emanuelsson1,2, Mai Winstrup4, Paul T. Vallelonga4, James E. Lee5, Ed J. Brook5, Jeffrey P. Severinghaus6, Taylor J. Fudge3, Elizabeth D. Keller2, W. Troy Baisden2, Richard C.A. Hindmarsh7, Peter D. Neff8, Thomas Blunier4, Ross Edwards9, Paul A. Mayewski10, Sepp Kipfstuhl11, Christo Buizert5, Silvia Canessa2, Ruzica Dadic1, Helle 10 A. Kjær4, Andrei Kurbatov10, Dongqi Zhang12,13, Ed D. Waddington3, Giovanni Baccolo14, Thomas Beers10, Hannah J. Brightley1,2, Lionel Carter1, David Clemens-Sewall15, Viorela G. Ciobanu4, Barbara Delmonte14, Lukas Eling1,2, Aja A. Ellis16, Shruthi Ganesh17, Nicholas R. Golledge1,2, Skylar Haines10, Michael Handley10, Robert L. Hawley15, Chad M. Hogan18, Katelyn M. Johnson1,2, Elena Korotkikh10, Daniel P. Lowry1, Darcy Mandeno1, Robert M. McKay1, James A. Menking5, Timothy R. Naish1, 15 Caroline Noerling11, Agathe Ollive19, Anaïs Orsi20, Bernadette C. Proemse18, Alexander R. Pyne1, Rebecca L. Pyne2, James Renwick1, Reed P. Scherer21, Stefanie Semper22, M. Simonsen4, Sharon B. Sneed10, Eric J., Steig3, Andrea Tuohy23, Abhijith Ulayottil Venugopal1,2, Fernando Valero-Delgado11, Janani Venkatesh17, Feitang Wang24, Shimeng -
Rapid Cenozoic Glaciation of Antarctica Induced by Declining
letters to nature 17. Huang, Y. et al. Logic gates and computation from assembled nanowire building blocks. Science 294, Early Cretaceous6, yet is thought to have remained mostly ice-free, 1313–1317 (2001). 18. Chen, C.-L. Elements of Optoelectronics and Fiber Optics (Irwin, Chicago, 1996). vegetated, and with mean annual temperatures well above freezing 4,7 19. Wang, J., Gudiksen, M. S., Duan, X., Cui, Y. & Lieber, C. M. Highly polarized photoluminescence and until the Eocene/Oligocene boundary . Evidence for cooling and polarization sensitive photodetectors from single indium phosphide nanowires. Science 293, the sudden growth of an East Antarctic Ice Sheet (EAIS) comes 1455–1457 (2001). from marine records (refs 1–3), in which the gradual cooling from 20. Bagnall, D. M., Ullrich, B., Sakai, H. & Segawa, Y. Micro-cavity lasing of optically excited CdS thin films at room temperature. J. Cryst. Growth. 214/215, 1015–1018 (2000). the presumably ice-free warmth of the Early Tertiary to the cold 21. Bagnell, D. M., Ullrich, B., Qiu, X. G., Segawa, Y. & Sakai, H. Microcavity lasing of optically excited ‘icehouse’ of the Late Cenozoic is punctuated by a sudden .1.0‰ cadmium sulphide thin films at room temperature. Opt. Lett. 24, 1278–1280 (1999). rise in benthic d18O values at ,34 million years (Myr). More direct 22. Huang, Y., Duan, X., Cui, Y. & Lieber, C. M. GaN nanowire nanodevices. Nano Lett. 2, 101–104 (2002). evidence of cooling and glaciation near the Eocene/Oligocene 8 23. Gudiksen, G. S., Lauhon, L. J., Wang, J., Smith, D. & Lieber, C. M. Growth of nanowire superlattice boundary is provided by drilling on the East Antarctic margin , structures for nanoscale photonics and electronics. -
Asynchronous Antarctic and Greenland Ice-Volume Contributions to the Last Interglacial Sea-Level Highstand
ARTICLE https://doi.org/10.1038/s41467-019-12874-3 OPEN Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand Eelco J. Rohling 1,2,7*, Fiona D. Hibbert 1,7*, Katharine M. Grant1, Eirik V. Galaasen 3, Nil Irvalı 3, Helga F. Kleiven 3, Gianluca Marino1,4, Ulysses Ninnemann3, Andrew P. Roberts1, Yair Rosenthal5, Hartmut Schulz6, Felicity H. Williams 1 & Jimin Yu 1 1234567890():,; The last interglacial (LIG; ~130 to ~118 thousand years ago, ka) was the last time global sea level rose well above the present level. Greenland Ice Sheet (GrIS) contributions were insufficient to explain the highstand, so that substantial Antarctic Ice Sheet (AIS) reduction is implied. However, the nature and drivers of GrIS and AIS reductions remain enigmatic, even though they may be critical for understanding future sea-level rise. Here we complement existing records with new data, and reveal that the LIG contained an AIS-derived highstand from ~129.5 to ~125 ka, a lowstand centred on 125–124 ka, and joint AIS + GrIS contributions from ~123.5 to ~118 ka. Moreover, a dual substructure within the first highstand suggests temporal variability in the AIS contributions. Implied rates of sea-level rise are high (up to several meters per century; m c−1), and lend credibility to high rates inferred by ice modelling under certain ice-shelf instability parameterisations. 1 Research School of Earth Sciences, The Australian National University, Canberra, ACT 2601, Australia. 2 Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK. 3 Department of Earth Science and Bjerknes Centre for Climate Research, University of Bergen, Allegaten 41, 5007 Bergen, Norway. -
PROGETTO ANTARTIDE Rapporto Sulla Campagna Antartica Estate Australe 1996
PROGRAMMA NAZIONALE DI RICERCHE IN ANTARTIDE Rapporto sulla Campagna Antartica Estate Australe 1996 - 97 Dodicesima Spedizione PROGETTO ANTARTIDE ANT 97/02 PROGRAMMA NAZIONALE DI RICERCHE IN ANTARTIDE Rapporto sulla Campagna Antartica Estate Australe 1996 - 97 Dodicesima Spedizione A cura di J. Mϋller, T. Pugliatti, M.C. Ramorino, C.A. Ricci PROGETTO ANTARTIDE ENEA - Progetto Antartide Via Anguillarese,301 c.p.2400,00100 Roma A.D. Tel.: 06-30484816,Fax:06-30484893,E-mail:[email protected] I N D I C E Premessa SETTORE 1 - EVOLUZIONE GEOLOGICA DEL CONTINENTE ANTARTICO E DELL'OCEANO MERIDIONALE Area Tematica 1a Evoluzione Geologica del Continente Antartico Progetto 1a.1 Evoluzione del cratone est-antartico e del margine paleo-pacifico del Gondwana.3 Progetto 1a.2 Evoluzione mesozoica e cenozoica del Mare di Ross ed aree adiacenti..............11 Progetto 1a.3 Magmatismo Cenozoico del margine occidentale antartico..................................17 Progetto 1a.4 Cartografia geologica, geomorfologica e geofisica ...............................................18 Area Tematica 1b-c Margini della Placca Antartica e Bacini Periantartici Progetto 1b-c.1 Strutture crostali ed evoluzione cenozoica della Penisola Antartica e del margine coniugato cileno ......................................................................................25 Progetto 1b-c.2 Indagini geofisiche sul sistema deposizionale glaciale al margine pacifico della Penisola Antartica.........................................................................................42 -
Calving Processes and the Dynamics of Calving Glaciers ⁎ Douglas I
Earth-Science Reviews 82 (2007) 143–179 www.elsevier.com/locate/earscirev Calving processes and the dynamics of calving glaciers ⁎ Douglas I. Benn a,b, , Charles R. Warren a, Ruth H. Mottram a a School of Geography and Geosciences, University of St Andrews, KY16 9AL, UK b The University Centre in Svalbard, PO Box 156, N-9171 Longyearbyen, Norway Received 26 October 2006; accepted 13 February 2007 Available online 27 February 2007 Abstract Calving of icebergs is an important component of mass loss from the polar ice sheets and glaciers in many parts of the world. Calving rates can increase dramatically in response to increases in velocity and/or retreat of the glacier margin, with important implications for sea level change. Despite their importance, calving and related dynamic processes are poorly represented in the current generation of ice sheet models. This is largely because understanding the ‘calving problem’ involves several other long-standing problems in glaciology, combined with the difficulties and dangers of field data collection. In this paper, we systematically review different aspects of the calving problem, and outline a new framework for representing calving processes in ice sheet models. We define a hierarchy of calving processes, to distinguish those that exert a fundamental control on the position of the ice margin from more localised processes responsible for individual calving events. The first-order control on calving is the strain rate arising from spatial variations in velocity (particularly sliding speed), which determines the location and depth of surface crevasses. Superimposed on this first-order process are second-order processes that can further erode the ice margin. -
Late Pleistocene Interactions of East and West Antarctic Ice-Flow Regim.Es: Evidence From
J oumal oJ Glaciology, r·ol. 42, S o. 142, 1996 Late Pleistocene interactions of East and West Antarctic ice-flow regim.es: evidence from. the McMurdo Ice Shelf THO}'IAS B . KELLOGG, TERRY H UG HES AND D .\VJD!\ E. KELLOGG Depa rtmen t oJ Geo logical Sciences alld Institute for QJlatemm) Studies, UI/ iversilj' oJ ,\Jail/ e, Orono , "faine 04469. [j.S. A. ABSTRACT. \Ve prese nt new interpreta ti ons of d eglacia tion in M cMurdo Sound and the wes tern R oss Sea, with o bservati onall y based reconstructi ons of interacti ons between Eas t a nd \Ves t Antarcti c ice a t the las t glacial maximum (LG YI ), 16 000, 12 000, 8000 a nd 4000 BP. At the LG M , East Anta rctic ice fr om Muloek Glacier spli t; one bra nch turned wes tward south of R oss Tsland b ut the other bra nch rounded R oss Island before fl owing south"'est in to lVf cMurdo Sound. This fl ow regime, constrained b y a n ice sa ddle north of R n. s Isla nd, is consisten t wi th the reconstruc ti on of Stuiyer a nd others (198I a ) . After the LG lVI. , grounding-line retreat was m ost ra pid in areas \~ ' i th greates t wa ter d epth, es pecially a long th e Vic toria Land coast. By 12 000 BP , the ice-flow regime in :'.1cMurdo Sound c ha nged to through-flowing l\1ulock G lacier ice, with lesse r contributions from K oettlitz, Blue a nd F crra r Glaciers, because the formcr ice saddle north of R oss Isla nd was repl aced by a d om e. -
Anatomy of the Marine Ice Cliff Instability
Anatomy of the Marine Ice Cliff Instability Jeremy N. Bassis1, Brandon Berg2, Doug Benn3 1Department of Climate and Space, University of Michigan, Ann Arbor, MI, USA 2Department of Physics, University of Michigan, Ann Arbor, MI, USA 3School of Geography and Sustainable Development, St. Andrews University, Scotland Ice sheets grounded on retrograde beds are susceptible to disintegration through a process called the marine ice sheet instability. This instability results from the dynamic thinning of ice near the grounding zone separating floating from grounded portions of the ice sheet. Recently, a new instability called the marine ice cliff instability has been proposed. Unlike the marine ice sheet instability, the marine ice cliff instability is controlled by the brittle failure of ice and thus has the potential to result in much more rapid ice sheet collapse. Here we explore the interplay between ductile and brittle processes using a model where ice obeys the usual power-law creep rheology of intact ice up to a yield strength. Above the yield strength, we introduce a separate, much weaker rheology, that incorporates quasi-brittle failure along faults and fractures. We first tested the model by applying it to study the formation of localized rifts in shear zones of idealized ice shelves. These experiments show that wide rifts localize along the shear margins and portions of the ice shelf where the stress in the ice exceeds the yield strength. These rifts decrease the buttressing capacity of the ice shelves, but can also extend to become the detachment boundary of icebergs. Next, application of the model to idealized glaciers shows that for grounded glaciers, failure localizes near the terminus in “serac” type slumping events followed by buoyant calving of the submerged portion of the glacier. -
The Ross Sea: a Valuable Reference Area to Assess the Effects of Climate Change
IP (number) Agenda Item: CEP 7e, ATCM 13 Presented by: ASOC Original: English The Ross Sea: A Valuable Reference Area to Assess the Effects of Climate Change 1 IP (number) Summary International Panel on Climate Change models predict that the Ross Sea will be the last portion of the Southern Ocean with sea ice year round. Currently, the Ross Sea ecosystem is considered to be relatively little affected by direct human-related impacts other than the past exploitation of marine mammals along its slope and the recent exploratory Antarctic toothfish fishery. The indirect human impacts of CO2 pollution on melting ice and ocean acidification have yet to be felt. The Ross Sea - with its several very long biotic and hydrographic data sets - constitutes an important reference area to gauge the ecosystem effects of climate change and distinguish those effects from the effects of current fisheries, tourism, and historic overexploitation and recovery or lack of recovery of some seal, whale, and fish populations elsewhere. This, in conjunction with a range of other scientific and biological reasons that has been laid out in prior ASOC papers, underpins why the Ross Sea should be included as a key component in the network of marine protected areas currently being considered for the Southern Ocean by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). 1. Introduction Over the past few years, ASOC has put forward a number of papers making the ‘science case’ for supporting full protection of the Ross Sea slope and shelf,1 in the context of establishing an important component of a representative network of MPAs in the Southern Ocean.2 This paper focuses on the climate reference zone potential of the Ross Sea. -
Antarctica's Drygalski Ice Tongue
Antarctica’s Drygalski Ice Tongue 1988 2002 Tongue Growth, 1988–2002 The 20-kilometer wide floating slab, known as the Drygalski Ice Tongue, is being pushed into McMurdo Sound, fed by the David Glacier in East Antarctica. Although the sea eats away its ragged sides, the Tongue continues to grow, as shown in this image progression from 1988 (top) to 2002 (middle). Drygalski’s 10-kilometer growth over those 14 years is shown on the bottom picture (red line), and is one measure of how fast some of the Antarctic ice sheet is moving into the sea. www.nasa.gov Antarctica’s Drygalski Ice Tongue Goddard Space Flight Center A Giant Tongue of Ice To meet this critical need, data from over a thousand In these satellite images, the Drygalski Ice Tongue Landsat 7 satellite images like those featured here juts out from the icy land of Antarctica into McMurdo were joined into the most detailed, high-resolution Sound like a pier. Drygalski is a floating extension of natural-color map ever produced of Antarctica. The a land-based glacier. It is one of the largest floating Landsat Image Mosaic of Antarctica (LIMA) offers objects in the world, and contains ice that first fell views of the southernmost continent on Earth in ten as snow on the ice sheet thousands of years ago. times greater detail than previously possible. Some Change is the norm for all glaciers, even for a behemoth locations in LIMA have not even been mapped before! the size of Drygalski. Glacier creation begins when “This is like having a room aboard Landsat to see the more snow falls than melts, and gradually builds up whole ice sheet, yet being able to swoop down to over time. -
A Speculative Stratigraphic Model for the Central Ross Embayment REED P
A speculative stratigraphic model for the central Ross embayment REED P. SCHERER , Department of Geology and Geography, University of Massachusetts, Amherst, Massachusetts 01003 Present address: Institute of Earth Sciences, Uppsala University, Uppsala, Sweden. he general character and geometry of sediments of the Available sub-ice sediments from the Ross embayment TRoss Sea are known from extensive seismic surveys (e.g., include 53 short gravity cores recovered from beneath the Anderson and Bartek 1992, PP. 231-264) and stratigraphic southern Ross Ice Shelf during the Ross Ice Shelf Project drilling during Deep Sea Drilling Project (DSDP), leg 28 (sites (RISP) (Webb et al. 1979), sediments recovered from Crary Ice 270-273) (Hayes and Frakes 1975, pp. 919-942; Savage and Rise (CIR) during the 1987-1988 field season (Bindschadler, Ciesielski 1983, pp. 555-559), Cenozoic Investigations of the Koci, and Iken 1988), and sediments recovered from beneath Ross Sea-1 (CIROS-1) (Barrett 1989), and McMurdo Sound ice stream B in the vicinity of the Upstream B camp (UpB) Sediment and Tectonic Studies-1 (MSSTS-1) (Barrett and (Engelhardt et al. 1990) during five field seasons on the ice McKelvey 1986), as well as numerous piston and gravity cores sheet (figure 1). All of the recovered west antarctic interior across the Ross Sea. In contrast, the stratigraphic record sediments are glacial diamictons containing a mixture of par- beneath the west antarctic ice sheet and Ross Ice Shelf is very ticles, including diatom fossils derived from deposits of vari- poorly known. Data available from beneath the Ross Ice Shelf ous Cenozoic ages (Scherer 1992). -
Open-File Report 2007-1047, Extended Abstracts
U.S. Geological Survey Open-File Report 2007-1047 Antarctica: A Keystone in a Changing World—Online Proceedings for the 10th International Symposium on Antarctic Earth Sciences Santa Barbara, California, U.S.A.—August 26 to September 1, 2007 Edited by Alan Cooper, Carol Raymond, and the 10th ISAES Editorial Team 2007 Extended Abstracts Extended Abstract 001 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea001.pdf Ross Aged Ductile Shearing in the Granitic Rocks of the Wilson Terrane, Deep Freeze Range area, north Victoria Land (Antarctica) by Federico Rossetti, Gianluca Vignaroli, Fabrizio Balsamo, and Thomas Theye Extended Abstract 002 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea002.pdf Postcollisional Magmatism of the Ross Orogeny (Victoria Land, Antarctica): a Granite- Lamprophyre Genetic Link S. Rocchi, G. Di Vincenzo, C. Ghezzo, and I. Nardini Extended Abstract 003 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea003.pdf Age of Boron- and Phosphorus-Rich Paragneisses and Associated Orthogneisses, Larsemann Hills: New Constraints from SHRIMP U-Pb Zircon Geochronology by C. J. Carson, E.S. Grew, S.D. Boger, C.M. Fanning and A.G. Christy Extended Abstract 004 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea004.pdf Terrane Correlation between Antarctica, Mozambique and Sri Lanka: Comparisons of Geochronology, Lithology, Structure And Metamorphism G.H. Grantham, P.H. Macey, B.A. Ingram, M.P. Roberts, R.A. Armstrong, T. Hokada, K. by Shiraishi, A. Bisnath, and V. Manhica Extended Abstract 005 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea005.pdf New Approaches and Progress in the Use of Polar Marine Diatoms in Reconstructing Sea Ice Distribution by A.