DOCSLIB.ORG

Landscape Evolution of the Dry Valleys, Transantarctic Mountains: Tectonic Implications David E

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Landscape Evolution of the Dry Valleys, Transantarctic Mountains: Tectonic Implications David E The University of Maine DigitalCommons@UMaine Earth Science Faculty Scholarship Earth Sciences 6-10-1995 Landscape Evolution of the Dry Valleys, Transantarctic Mountains: Tectonic Implications David E. Sugden George H. Denton University of Maine - Main, [email protected] David R. Marchant Follow this and additional works at: https://digitalcommons.library.umaine.edu/ers_facpub Part of the Earth Sciences Commons Repository Citation Sugden, David E.; Denton, George H.; and Marchant, David R., "Landscape Evolution of the Dry Valleys, Transantarctic Mountains: Tectonic Implications" (1995). Earth Science Faculty Scholarship. 55. https://digitalcommons.library.umaine.edu/ers_facpub/55 This Article is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Earth Science Faculty Scholarship by an authorized administrator of DigitalCommons@UMaine. For more information, please contact [email protected]. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 100, NO. B7, PAGES 9949-9967, JUNE 10, 1995 Landscapeevolution of the Dry Valleys,Transantarctic Mountains: Tectonicimplications David E. Sugden Departmentof Geography,University of Edinburgh,Edinburgh, Scotland GeorgeH. Denton Departmentof GeologicalSciences and Institute for QuaternaryStudies, University of Maine,Orono DavidR. Marchant• Departmentof Geography,University of Edinburgh,Edinburgh, Scotland Abstract. Thereare differentviews about the amount and timing of surfaceuplift in the TransantarcticMountains and the geophysicalmechanisms involved. Our new interpretationof the landscapeevolution and tectonichistory of the Dry Valleysarea of the Transantarctic Mountainsis basedon geomorphic mapping of anarea of 10,000km 2. Thelandforms are dated mainlyby their associationwith volcanicashes and glaciomarine deposits and this permitsa reconsmactionof the stagesand timing of landscapeevolution. Followinga loweringof baselevel about55 m.y. ago,there was a phaseof rapid denudationassociated with planationand escarpmentretreat, probably under semiarid conditions. Eventually, downcutting by rivers,aided in placesby glaciers,graded valleys to nearpresent sea level. The main valleyswere floodedby the seain the Mioceneduring a phaseof subsidencebefore experiencing a final stageof modest upwarpingnear the coast. There hasbeen remarkably little landformchange under the stable, cold,polar conditions of the last 15 m.y. It is difficult to explainthe SiriusGroup deposits, which occurat high elevationsin the area,if they are Pliocenein age. Overall,denudation may have removeda wedgeof rock with a thicknessof over 4 km at the coastdeclining to 1 km at a point 75 km inland,which is in goodagreement with the resultsof existingapatite fission track analyses. It is suggestedthat denudation reflects the differencesin baselevel causedby high elevationat the time of extensiondue to underplatingand the subsequentrole of thermaluplift and flexural isostasy.Most crustaluplift (2-4 km) is inferredto haveoccurred in the early Cenozoicwith 400 m of subsidencein the Miocenefollowed by 300 m of uplift in the Pliocene. Introduction debate,we do not considerthe issuein this paper(but seeDenton et al, [ 1993]). The aim of this paperis to relate geomorphologicalevidence Extending acrossAntarctica, the Transantarctic Mountains of landscapeevolution to the tectonicprocesses in the Dry Valleys rise to over 4000 m in the Royal SocietyRange. The mountains of the Transantarctic Mountains. Like the Drakensberg consistof gentlytilted blocksof sedimentaryrocks (Devonian- Mountains in southernAfrica and the Great Dividing Range in Triassic Beacon Supergroup)overlying Pre-Cambrian-Devonian Australia the Transantarctic Mountains consist of an eroded basementand are intruded and cappedby Jurassicdolerites and plateau edge characteristicof high-elevationpassive continental basalts. The mountainscomprise the uplifted rift flank of the margins [Gilchrist and Summerfield,1990]. Understandingthe West AntarcticRift System[Behrendt et al., 1991], which has landscapeevolution of the mountainsis importantbecause it can been periodicallyactive since the separationof Antarcticaand be used to constrainvarious geophysical models of the tectonic Australia [Tessensohnand Worrier, 1991]. processesassociated withsuch margins. The tectonic history of Thereis considerableuncertainty about the mount and theTransantarctic Mountains isintimately involved ina debatetiming of uplift and the tectonic processes involved. Apafite aboutthe stability ofthe East Antarctic IceSheet. Although our fissiontrack analysis indicates thatthere has been about 5 km of new interpretationof landscapeevolution has implicationsfor the denudationin the Dry Valleys area since the early Cenozoic; denudationrates were high in the early Cenozoicbefore tailing off 1NowatInstitute forQuaternary Studies, University ofMaine, [Gleadowand Fitzgerald, 1987; Fitzgerald, 1992; Brown et al., Orono. 1994]. This implies that significantlocal relief existedaround 55 m.y. ago and that the rift flank was alreadyelevated with respect to base level, either as a consequenceof thermal uplift or Copyright1995 by theAmerican Geophysical Union. underplatingor as a result of the rifting of a preexisting,high- elevation surface. This interpretationagrees with evidenceof Papernumber 94JB02875. 0148-0227/95 / 94JB-02875$05.00 limited recent surface uplift as inferred from the elevation of 9949 9950 SUGDEN ET AL.: DRY VALLEY LANDSCAPE EVOLUTION undisturbedsubaerial Pliocene volcanic cones in Taylor Valley denudationprofiles from the northernsides of Ferrar and Wright [Wilchet al., 1993a]. A differentline of evidencesuggests that valleys[Fitzgerald et al., 1986] imply that the blockhas behaved there has been substantialsurface uplift of parts of the as one unit since the early Tertiary, thus holding constantone TransantarcticMountains of 1-2 km over the past 2-3 m.y. variable in landscapeevolution. Second,the block contains [McKelveyet al., 1991; Webbet al., 1984; Webband Harwood, outcropsof SiriusGroup deposits at high elevations(2650 rn on 1987]. This view is based on the existence of the remains of Mount Feather), critical evidence which must eventually be temperatevegetation of presumedPliocene age (2-3 Ma) in Sirius accommodatedin any explanation. Third, the valleys containa Group depositsat high elevations. There are some 30 Sirius terrestrial record of surface deposits extending back to the Groupoutcrops in theTransantarctic Mountains flanking the Ross Miocene, thus providingan unprecedentedlylong window into Ice Shelfbetween latitudes 86øS and 78øS and further outcrops in mountainevolution. A disadvantageof a studyrestricted to one the highmountains of SouthernVictoria Land in the Dry Valleys blockis that any conclusionscannot necessarily be extrapolatedto and the Prince Albert Mountains [Denton et al., 1993; Verbers other areas of the Transantarctic Mountains. and Van der Wateren,1992]. The datingof the depositsdepends There have been two main phases of interest in the criticallyon the age and origin of reworkeddiatoms thought to geomorphologicalevolution of the Dry Valleys. The first have originatedin marine basinsin East Antarcticaand to have involved geologistsof Scott's and Shackleton'sexpeditions, been subsequentlytransported to the mountainsby ice. The whoseinitial observationson the great age of the landscapeand biostratigraphicage of certainof the diatomshas been confirmed the modestimpact of presentglaciers make relevantreading to by isotopicdating of a volcanicash layer in the offshoreCIROS-2 this day [Ferrar, 1907; David and Priestley,1914; Wright and core [Barrett et al., 1992]. Severalother supportinglines of Priestley,1922; Taylor, 1922]. The secondphase accompanied evidencefor recentsurface uplift have beencollated by Behrendt U.S. and New Zealand activities after the International andCooper [ 1991],including the "youthfulappearance" of the rift GeophysicalYear in 1957. In numerouspapers elaborating the shoulderand the presenceof offshoreHolocene fault scarps. geologicaland glacialhistory of the area, a generalconclusion Thesevarious views were synthesizedby Fitzgerald[1992] who was that the main valleysowed their origin to earlier stagesof suggestedthat crustal uplift of the TransantarcticMountains in glaciationunder more temperateconditions [e.g., Taylor, 1922; the Dry Valleys area has occurredthroughout the Cenozoicbut Bull et al., 1962; Calkin, 1974a; Denton et al., 1971, 1984; with two acceleratedpulses at 55-40 Ma and 10-0 Ma. Nichols,1971; Selbyand Wilson,1971]. This view is consistent In view of the uncertaintyabout the timingof the uplift, it is with the argumentsof Van der Waterenand Verbers[1992] in difficult to relate the tectonic evolution of the mountains to the northernVictoria Land. In addition, there is recognitionof the widerprocesses of platetectonics. At leasttwo periodsof rifting particularrole of cold desertagents of erosion. For example, have been inferred from study of the Ross Sea embayment Selby [1971, 1974] recognized the prevalence of straight [Tessensohnand Worner,1991; Cooperet al., 1991;LeMasurier rectilinearslopes and tentlikeridges which he attributedto salt and Rex, 1991]. The first phasebegan in the Mesozoic(possibly weatheringand wind deflationcharacteristic of this type of frigid, linked to the separationof Antarcticaand Australia) and was arid environment. The characteristicslope angles were also associatedwith widespreadgraben downfaultingand crustal related to rock strengthcharacteristics
Load more

Recommended publications
  • Geochemistry This
    TORONTOTORONTO Vol. 8, No. 4 April 1998 Call for Papers GSA TODAY — page C1 A Publication of the Geological Society of America Electronic Abstracts Submission — page C3 Antarctic Neogene Landscapes—In the 1998 Registration Refrigerator or in the Deep Freeze? Annual Issue Meeting — June GSA Today Introduction The present Molly F. Miller, Department of Geology, Box 117-B, Vanderbilt Antarctic landscape undergoes very University, Nashville, TN 37235, [email protected] slow environmental change because it is almost entirely covered by a thick, slow-moving ice sheet and thus effectively locked in a Mark C. G. Mabin, Department of Tropical Environmental Studies deep freeze. The ice sheet–landscape system is essentially stable, and Geography, James Cook University, Townsville, Queensland 4811, Australia, [email protected] Antarctic—Introduction continued on p. 2 Atmospheric Transport of Diatoms in the Antarctic Sirius Group: Pliocene Deep Freeze Arjen P. Stroeven, Department of Quaternary Research, Stockholm University, S-106 91 Stockholm, Sweden Lloyd H. Burckle, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964 Johan Kleman, Department of Physical Geography, Stockholm University, S-106, 91 Stockholm, Sweden Michael L. Prentice, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824 INTRODUCTION How did young diatoms (including some with ranges from the Pliocene to the Pleistocene) get into the Sirius Group on the slopes of the Transantarctic Mountains? Dynamicists argue for emplacement by a wet-based ice sheet that advanced across East Antarctica and the Transantarctic Mountains after flooding of interior basins by relatively warm marine waters [2 to 5 °C according to Webb and Harwood (1991)].
    [Show full text]
  • Landscape Evolution and Preservation of Ice Over One Million Years Old Quantified with Cosmogenic Nuclides 26Al, 10Be, and 21Ne, Ong Valley, Antarctica Theodore C
    University of North Dakota UND Scholarly Commons Theses and Dissertations Theses, Dissertations, and Senior Projects 2014 Landscape evolution and preservation of ice over one million years old quantified with cosmogenic nuclides 26Al, 10Be, and 21Ne, Ong Valley, Antarctica Theodore C. Bibby University of North Dakota Follow this and additional works at: https://commons.und.edu/theses Part of the Geology Commons Recommended Citation Bibby, Theodore C., "Landscape evolution and preservation of ice over one million years old quantified with cosmogenic nuclides 26Al, 10Be, and 21Ne, Ong Valley, Antarctica" (2014). Theses and Dissertations. 20. https://commons.und.edu/theses/20 This Dissertation is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. LANDSCAPE EVOLUTION AND PRESERVATION OF ICE OVER ONE MILLION YEARS OLD QUANTIFIED WITH COSMOGENIC NUCLIDES 26AL, 10BE, AND 21NE, ONG VALLEY, ANTARCTICA by Theodore C. Bibby Bachelor of Science, Florida State University, 2009 A Dissertation Submitted to the Graduate Faculty of the University of North Dakota in partial fulfillment of the requirements for the degree of Doctor of Philosophy Grand Forks, North Dakota December 2014 Copyright 2014 Theodore C. Bibby ii This dissertation, submitted by Theodore C. Bibby in partial fulfillment of the requirements for the Degree of Doctor of Philosophy from the University of North Dakota, has been read by the Faculty Advisory Committee under whom the work has been done and is hereby approved.
    [Show full text]
  • The Commonwealth Trans-Antarctic Expedition 1955-1958
    THE COMMONWEALTH TRANS-ANTARCTIC EXPEDITION 1955-1958 HOW THE CROSSING OF ANTARCTICA MOVED NEW ZEALAND TO RECOGNISE ITS ANTARCTIC HERITAGE AND TAKE AN EQUAL PLACE AMONG ANTARCTIC NATIONS A thesis submitted in fulfilment of the requirements for the Degree PhD - Doctor of Philosophy (Antarctic Studies – History) University of Canterbury Gateway Antarctica Stephen Walter Hicks 2015 Statement of Authority & Originality I certify that the work in this thesis has not been previously submitted for a degree nor has it been submitted as part of requirements for a degree except as fully acknowledged within the text. I also certify that the thesis has been written by me. Any help that I have received in my research and the preparation of the thesis itself has been acknowledged. In addition, I certify that all information sources and literature used are indicated in the thesis. Elements of material covered in Chapter 4 and 5 have been published in: Electronic version: Stephen Hicks, Bryan Storey, Philippa Mein-Smith, ‘Against All Odds: the birth of the Commonwealth Trans-Antarctic Expedition, 1955-1958’, Polar Record, Volume00,(0), pp.1-12, (2011), Cambridge University Press, 2011. Print version: Stephen Hicks, Bryan Storey, Philippa Mein-Smith, ‘Against All Odds: the birth of the Commonwealth Trans-Antarctic Expedition, 1955-1958’, Polar Record, Volume 49, Issue 1, pp. 50-61, Cambridge University Press, 2013 Signature of Candidate ________________________________ Table of Contents Foreword ..................................................................................................................................
    [Show full text]
  • Draft ASMA Plan for Dry Valleys
    Measure 18 (2015) Management Plan for Antarctic Specially Managed Area No. 2 MCMURDO DRY VALLEYS, SOUTHERN VICTORIA LAND Introduction The McMurdo Dry Valleys are the largest relatively ice-free region in Antarctica with approximately thirty percent of the ground surface largely free of snow and ice. The region encompasses a cold desert ecosystem, whose climate is not only cold and extremely arid (in the Wright Valley the mean annual temperature is –19.8°C and annual precipitation is less than 100 mm water equivalent), but also windy. The landscape of the Area contains mountain ranges, nunataks, glaciers, ice-free valleys, coastline, ice-covered lakes, ponds, meltwater streams, arid patterned soils and permafrost, sand dunes, and interconnected watershed systems. These watersheds have a regional influence on the McMurdo Sound marine ecosystem. The Area’s location, where large-scale seasonal shifts in the water phase occur, is of great importance to the study of climate change. Through shifts in the ice-water balance over time, resulting in contraction and expansion of hydrological features and the accumulations of trace gases in ancient snow, the McMurdo Dry Valley terrain also contains records of past climate change. The extreme climate of the region serves as an important analogue for the conditions of ancient Earth and contemporary Mars, where such climate may have dominated the evolution of landscape and biota. The Area was jointly proposed by the United States and New Zealand and adopted through Measure 1 (2004). This Management Plan aims to ensure the long-term protection of this unique environment, and to safeguard its values for the conduct of scientific research, education, and more general forms of appreciation.
    [Show full text]
  • Xrf Analyses of Granitoids and Associated
    X.R.F ANALYSES OF GRANITOIDS AND ASSOCIATED ROCKS FROM SOUTH VICTORIA LAND, ANTARCTICA K. Palmer Analytical Facility Victoria University of Wellington Private Bag Wellington NEW ZEALAND Contents Page 1 Introduction 1 Sample Preparation 2 Analytical Procedures 4 Acknowledgments 5 References 6 Tables of Analytical Data 11 Tables of Sample Descriptions 17 Location Maps 22 Appendix 1 23 Appendix 2 Research School of Earth Sciences Geology Board of Studies Publication No.3 Victoria University of Wellington ISSN 0113-1168 Analytical Facility Contribution No. 12 ISSN 0111-1337 Antarctic Data Series No.13 ISSN 0375-8192 1987 INTRODUCTION The granitoid rocks of South Victoria Land are represented in some of the earliest geological studies of Antarctica. Indeed as early as 1841 granitoids were dredged from the sea-floor off Victoria Land on the voyages of the Erebus and Terror. Early workers such as Ferrar and Prior described granitoids collected in situ by members of the Discovery expedition (1901-1904). Some years later further granitoid descriptions and the occasional chemical analysis were presented by such workers as David, Priestly, Mawson and Smith. In more recent times, samples collected by Gunn and Warren (1962) and analysed by the United States Geological Survey were presented in Harrington et.al. (1967). The first detailed study of granitoids in South Victoria Land was by Ghent & Henderson (1968) who, although examining only a small area in the lower Taylor Valley revealed for the first time the diverse range of granitoid types and emplacement processes in this region. This work was followed up by a relatively detailed major and trace element geochemical study, (Ghent,1970).
    [Show full text]
  • A Sedimentological Record of Early Miocene Ice Advance and Retreat, AND-2A Drill Hole, Mcmurdo Sound, Antarctica GEOSPHERE
    Research Paper GEOSPHERE A sedimentological record of early Miocene ice advance and retreat, AND-2A drill hole, McMurdo Sound, Antarctica 1 1 2 3 2 4 5 6 7 8 GEOSPHERE; v. 14, no. 4 B.D. Field , G.H. Browne , C.R. Fielding , F. Florindo , D.M. Harwood , S.A. Judge , L.A. Krissek , K.S. Panter , S. Passchier , S.F. Pekar , S. Sandroni9, and F.M. Talarico9,10 1 https://doi.org/10.1130/GES01592.1 GNS Science, PO Box 30368, Lower Hutt, New Zealand 2Department of Earth and Atmospheric Sciences, 126 Bessey Hall, University of Nebraska-Lincoln, Nebraska 68588- 0340, USA 3Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 1-00143 Rome, Italy 15 figures 4Department of Geology, College of Wooster, 944 College Mall, Wooster, Ohio 44691, USA 5School of Earth Sciences, Ohio State University, 125 South Oval Mall, Columbus, Ohio 43210, USA 6 CORRESPONDENCE: brad .field@ gns .cri.nz Department of Geology, Bowling Green State University, Bowling Green, Ohio 43402, USA 7Department of Earth & Environmental Sciences, Montclair State University, 252 Mallory Hall, 1 Normal Avenue, Montclair, New Jersey 07043, USA 8School of Earth & Environmental Sciences, Queen’s College, 65-30 Kissena Blvd., Flushing, New York 11367, USA CITATION: Field, B.D., Browne, G.H., Fielding, 9Museo Nazionale dell’Antartide, Università degli Studi di Siena, Via Laterina 8, Siena, Italy C.R., Florindo, F., Harwood, D.M., Judge, S.A., 10Dipartimento di Scienze Fisiche, della Terra e dell’Ambiente, Università degli Studi di Siena, Via Laterina 8, Siena, Italy Krissek, L.A., Panter, K.S., Passchier, S., Pekar, S.F., Sandroni, S., and Talarico, F.M., 2018, A sedimento- logical record of early Miocene ice advance and re- ABSTRACT antarctic Mountains glacial activity under precessional control in CS1 and treat, AND-2A drill hole, McMurdo Sound, Antarctica: Geosphere, v.
    [Show full text]
  • Fault Kinematic Studies in the Transantarctic Mountains, Southern Victoria Land TERRY J
    studies. Together these data will be used to develop a model to plate tectonic modeling. In R.A. Hodgson, S.P. Gay, Jr., and J.Y. of the structural architecture and motion history associated Benjamins (Eds.), Proceedings of the First International Conference with the Transantarctic Mountains in southern Victoria Land. on the New Basement Tectonics (Publication number 5). Utah Geo- logical Association. We thank Jane Ferrigno for cooperation and advice on Lucchita, B.K., J. Bowell, K.L. Edwards, E.M. Eliason, and H.M. Fergu- image selection; John Snowden, David Cunningham, and son. 1987. Multispectral Landsat images of Antarctica (U.S. Geo- Tracy Douglass at the Ohio State University Center for Map- logical Survey bulletin 1696). Washington, D.C.: U.S. Government ping for help with computer processing; and Carolyn Merry, Printing Office. Gary Murdock, and Ralph von Frese for helpful discussions Wilson, T.J. 1992. Mesozoic and Cenozoic kinematic evolution of the Transantarctic Mountains. In Y. Yoshida, K. Kaminuma, and K. concerning image analysis. This research was supported by Shiraishi (Eds.), Recent progress in antarctic earth science. Tokyo: National Science Foundation grant OPP 90-18055 and by the Terra Scientific. Byrd Polar Research Center of Ohio State University. Wilson, T.J. 1993. Jurassic faulting and magmatism in the Transantarctic Mountains: Implication for Gondwana breakup. In R.H. Findlay, M.R. Banks, R. Unrug, and J. Veevers (Eds.), Gond- References wana 8—Assembly, evolution, and dispersal. Rotterdam: A.A. Balkema. Wilson, T.J., P. Braddock, R.J. Janosy, and R.J. Elliot. 1993. Fault kine- Isachsen, Y.W. 1974.
    [Show full text]
  • 2010-2011 Science Planning Summaries
    Find information about current Link to project web sites and USAP projects using the find information about the principal investigator, event research and people involved. number station, and other indexes. Science Program Indexes: 2010-2011 Find information about current USAP projects using the Project Web Sites principal investigator, event number station, and other Principal Investigator Index indexes. USAP Program Indexes Aeronomy and Astrophysics Dr. Vladimir Papitashvili, program manager Organisms and Ecosystems Find more information about USAP projects by viewing Dr. Roberta Marinelli, program manager individual project web sites. Earth Sciences Dr. Alexandra Isern, program manager Glaciology 2010-2011 Field Season Dr. Julie Palais, program manager Other Information: Ocean and Atmospheric Sciences Dr. Peter Milne, program manager Home Page Artists and Writers Peter West, program manager Station Schedules International Polar Year (IPY) Education and Outreach Air Operations Renee D. Crain, program manager Valentine Kass, program manager Staffed Field Camps Sandra Welch, program manager Event Numbering System Integrated System Science Dr. Lisa Clough, program manager Institution Index USAP Station and Ship Indexes Amundsen-Scott South Pole Station McMurdo Station Palmer Station RVIB Nathaniel B. Palmer ARSV Laurence M. Gould Special Projects ODEN Icebreaker Event Number Index Technical Event Index Deploying Team Members Index Project Web Sites: 2010-2011 Find information about current USAP projects using the Principal Investigator Event No. Project Title principal investigator, event number station, and other indexes. Ainley, David B-031-M Adelie Penguin response to climate change at the individual, colony and metapopulation levels Amsler, Charles B-022-P Collaborative Research: The Find more information about chemical ecology of shallow- USAP projects by viewing individual project web sites.
    [Show full text]
  • In This Issue
    rvin bse g S O ys th t r e a m E THE EARTH OBSERVER May/June 2003, Vol. 15, No. 3 In this issue ... EDITOR’S CORNER Meeting/Workshop Summaries Michael King Minutes of the March 2003 Aura Science EOS Senior Project Scientist Team Meeting ................................ 3 CERES Science Team Meeting ......... 9 CloudSat/CALIPSO Science Team I’m proud to announce that the International Academy of the Digital Arts Meeting Summary ....................... 14 and Sciences has selected two NASA Web sites for top honors in their ASTER Users Workshop ................. 17 respective categories. The NASA Home Page (at www.nasa.gov), managed SEEDS Update ................................ 23 by Brian Dunbar and his team at NASA Headquarters in Washington, D.C., Other Items of Interest won the Webby in the “Government & Law” category. And NASA’s Earth Observatory (at earthobservatory.nasa.gov), managed by David Herring and CCSDS Lossless Data Compression to be Available in HDF-4 and 5 ....... 19 his team at Goddard Space Flight Center in Greenbelt, MD, won the Webby Aqua Mission Sponsors 2003 Engineer- in the “Education” category. ing Competition ........................ 21 Additionally, both sites won “People’s Voice Awards” for their respective Kudos ................................................ 24 Earth’s Hidden Waters Tracked by categories. In keeping with the spirit of the Web’s capacity for global GRACE .................................... 25 interactivity, the People’s Voice Award is determined by a popular vote in NASA’s ESE Sponsors Creative Problem which anyone in the world can vote for their favorites in each of the Solving competition ................. 30 Webby’s thirty categories. Regular Features The Webby is the most coveted award by the on-line community (visit Earth Science Education Program www.webbyawards.com for details).
    [Show full text]
  • Silicon Isotopes Reveal a Non-Glacial Source of Silicon to Crescent Stream, Mcmurdo Dry Valleys, Antarctica
    Hirst, C., Opfergelt, S., Gaspard, F., Hendry, K., Hatton, J., Welch, S., Mcknight, D., & Lyons, W. B. (2020). Silicon isotopes reveal a non- glacial source of silicon to Crescent Stream, McMurdo Dry Valleys, Antarctica. Frontiers in Marine Science, 8, [229]. https://doi.org/10.3389/feart.2020.00229 Publisher's PDF, also known as Version of record License (if available): CC BY Link to published version (if available): 10.3389/feart.2020.00229 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Frontiers Media at https://www.frontiersin.org/articles/10.3389/feart.2020.00229/full. Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ feart-08-00229 June 26, 2020 Time: 15:43 # 1 ORIGINAL RESEARCH published: 26 June 2020 doi: 10.3389/feart.2020.00229 Silicon Isotopes Reveal a Non-glacial Source of Silicon to Crescent Stream, McMurdo Dry Valleys, Antarctica Catherine Hirst1*, Sophie Opfergelt1, François Gaspard1, Katharine R. Hendry2, Jade E. Hatton2, Susan Welch3, Diane M. McKnight4 and W. Berry Lyons3 1 Earth and Life Institute, Environmental Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium, 2 School of Earth Sciences, University of Bristol, Bristol, United Kingdom, 3 School of Earth Sciences, Byrd Polar and Climate Research Center, The Ohio State University, Columbus, OH, United States, 4 Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, United States In high latitude environments, silicon is supplied to river waters by both glacial and non- glacial chemical weathering.
    [Show full text]
  • Thesis Approval
    THESIS APPROVAL The abstract and thesis of Robin Rachelle Johnston for the Master of Science in Geology presented February 12, 2004, and accepted by the thesis committee and the department. COMMITTEE APPROVALS: ________________________________________ Andrew G. Fountain, Chair ________________________________________ Christina L. Hulbe ________________________________________ Martin J. Streck ________________________________________ Aslam Khalil Representative of the Office of Graduate Studies DEPARTMENTAL APPROVAL: ________________________________________ Michael L. Cummings, Chair Department of Geology ABSTRACT An abstract of the thesis of Robin Rachelle Johnston for the Master of Science in Geology presented February 12, 2004 Title: Channel Morphology and Surface Energy Balance on Taylor Glacier, Taylor Valley, Antarctica Deeply-incised channels on Taylor Glacier in Taylor Valley, Antarctica initiate as medial moraines traced tens of kilometers up-glacier, are aligned with the direction of flow, and at their most developed occupy about 40% of the ablation zone in the lower reaches of the glacier. Development of the South Channel occurs in three stages. The first stage, the 1st Steady State, is characterized by rather uniform development, where the channel widens at much less than 0.1 m yr-1 and deepens at much less than 0.01 m yr-1, maintaining a width to depth ratio of about 8. The second stage, the Transition Phase, is characterized by dramatic widening channel (from 10 to 110 m) and deepening (from 2 to 24 m). During this stage, the peak rate of widening is about 1.5 m yr-1 and the channel is about 25 times as wide as it is deep. The third stage of channel development, the 2nd Steady State, is characterized by a steady decrease in the rate of channel deepening and a leveling off of the width to depth ratio as the channel ceases to widen.
    [Show full text]
  • Reconstruction of LGM and Post LGM Glacial Environment of Mcmurdo Sound: Implications for Ice Dynamics, Depositional Systems and Glacial Isostatic Adjustment
    Reconstruction of LGM and Post LGM Glacial Environment of McMurdo Sound: Implications for Ice Dynamics, Depositional Systems and Glacial Isostatic Adjustment THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By James Edward Stutz Graduate Program in Geological Sciences The Ohio State University 2012 Master's Examination Committee: Dr. Terry Wilson, Advisor Dr. Larry Krissek Dr. Peter Webb Copyright by James Edward Stutz 2012 Abstract McMurdo Sound represents a landscape at the crossroads of the West and East Antarctic Ice Sheets and has seen repeated occupation by both cold and warm based ice. Current ice sheet reconstructions place grounded ice across McMurdo Sound at the Last Glacial Maximum (LGM), thus the seafloor is expected to display morphologic features recording the LGM glaciation. Analysis of high-resolution multibeam bathymetry data and seismic surveys documents landforms marking glacial-geological processes beneath and at the margins of the ice sheets and are used to help determine the extent and style of glacial behavior on glacially influenced continental margins. The dominant morphologic features on the seafloor of McMurdo Sound are channel systems emanating eastward from the fjords of the Transantarctic Mountains (TAM) coast and northward from beneath the McMurdo Ice Shelf. A wide range of channel systems is observed. MacKay Sea Valley, at the northern limit of McMurdo Sound, displays a 6-8km wide, u-shaped valley with lineations formed by streaming ice of the expanded MacKay Glacier. A large submarine outwash fan extends 10’s of km eastward from the mouth of the sea valley.
    [Show full text]