DOCSLIB.ORG

Subglacial Meltwater System, Sessrumir Valley, Western Asgard Range, Antarctica

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Subglacial Meltwater System, Sessrumir Valley, Western Asgard Range, Antarctica Subglacial meltwater system, Sessrumir Valley, western Asgard Range, Antarctica DAVID E. SUGDEN Department of Geography University of Edinburgh Edinburgh, Scotland DAVID R. MARCHANT Department of Geography University of Edinburgh Edinburgh, Scotland and Department of Geological Sciences and Institute of Quaternary Studies University of Maine Orono, Maine 04469 Figure 1. Field-based geomorphological map of the central part of the channel. GEORGE H. DENTON Department of Geological Sciences and and sharply incised into a smooth bedrock slope with an over- Institute of Quaternary Studies all gradient of 10-28°. The long profiles of the tributary chan- University of Maine nels are complex. Some fall continuously downslope to the Orono, Maine 04469 main channel. Others are discontinuous and the long profile is interrupted by potholes and rock bars. Commonly, conflu- ences are ungraded, and for example, tributaries may join each Channels and potholes occur in the mountains flanking the other and the main channel by means of a cliff. The overall McMurdo Dry Valleys. They have been described in the Quar- pattern of the tributary channels is dendritic in that they tend termain Mountains south of Taylor Glacier, in the Asgard and to merge into fewer, larger channels. There are, however, in- Olympus Range on either side of Wright Valley, and in the stances of bifurcation which lead to an anastomosing pattern. Convoy Range (Denton, Kellogg, and Prentice 1983; Denton In certain cases, rock channels 5-10 meters deep split and et al. 1984). These features are one of several lines of evidence rejoin at some point down-channel. used to infer that an ice sheet overrode the McMurdo Dry The channel system is associated with potholes tens of me- Valleys area from the southwest to the northeast in late Tertiary ters across and tens of meters deep. Typically the potholes are time. This view has been challenged by Selby (1986) and Au- circular in plan and have vertical or undercut sides. Cliffs may gustinus and Selby (1990), who suggested that there are al- surround the potholes on all sides or may be breached in one ternative explanations for the various line of evidence and that or two locations. Ice pools occupy the bottom of many poth- these need to be scrutinized further. For example, they sug- oles. Potholes commonly occur in three locations: at the con- gested that the channels and potholes were associated with fluence of two or more channels, at sharp corners along a local ice. Here, we examine the morphology of one channel channel, and on the gentle upper slope between the channels. system in Sessrumir Valley in the western Asgard Range (Ack- The morphology of the channel system is characterized in ert 1990) and conclude that it reflects subglacial meltwater ac- detail by forms associated with geomorphological processes tivity and is likely to have been associated with overriding ice. that have occurred since their formation. These include sand The channel system, which is 2.5 kilometers long and about dunes in the lee of north-facing cliffs as well as fretted and 600 meters wide, is cut into rock slopes along the flanks of an pitted rock surfaces. The floors of many channels are covered S-shaped butte marking the eastern wall of Sessrumir Valley. by an armor of pebbles with ventifacted facets and desert var- It begins at an elevation of 1,710 meters in the south and falls nish. These are commonly arranged into the form of ripples. to 1,510 meters in the north. Figures 1 and 2 show a field- The continuity, sinuosity, and confluent pattern of the chan- based geomorphological map of the central part of the channel nels and their association with potholes all point to the role of system and an oblique aerial photograph. The main channel water in their formation. Several other features point to the consists of five segments, each of which starts with a cliffed role of meltwater flowing hydrostatically in a subglacial en- "plunged pool" of 5-20 meters and runs for several hundred vironment. For example, these include the irregular long pro- meters before petering out at the next plunge pool. The chan- files, reverse gradients, anastomosing patterns cut into bedrock, nel segments increase in size to a maximum width of 145 me- and ungraded confluences. Such features are well known from ters and a depth of 25-50 meters. Tributary channels run into mid-latitude areas of former glaciation (Sugden and John 1976) the main channel from the slopes of the butte. They are cuffed and are explicable in terms of theories of subglacial hydrology 56 ANTARCTIC JOURNAL Figure 2. Oblique aerial photograph of the central part of the channel system. (Shreve 1972: Sharp, Gemmell, and Tison 1989). Large potholes to regional ice flow rather than local ice flow confined to sep- and their association with irregularities in a channel are also arate valleys. most easily explained by the high velocity streams, heavily Three points were made clear by our study: loaded with debris, which are characteristic of subglacial re- • The pattern and morphology of channels and potholes has gimes. revealed the existence of subglacial meltwater systems in the The channel system has been modified by wind and weath- Asgard Range. The pattern of the channels is consistent with ering since its formation. Fretting of the rock walls, salt weath- the hypothesis of overriding ice from the southwest. ering, sand dunes, and ventifacts arranged into ripples all add • The relationship of the channels to the underlying topo- detail to the morphology; however, wind action cannot explain graphy implies that the main features, such as the butte, the characteristic features of water action listed above. were present before the overriding glaciation. The overall pattern and site of the channels is consistent • Wind action accounts for the detailed morphology within with an origin beneath overriding ice. Firstly, the channels are the channel system, including fretting, sand dunes, and in the lee of a butte and their pattern suggests that meltwater ripples. originated on the butte. The most likely explanation of this This work was funded National Science Foundation grant DPP pattern is that the meltwater was derived from a zone of pres- 86-13842. Helicopter support was provided by the U.S. Navy. sure melting on the upstream side of the butte beneath ov- erriding ice. Secondly, similar channels are also incised into the saddles elsewhere in the main divide of the Asgard Range; References for example, the saddle in the headwall of the adjacent valley at an altitude of 1,750 meters is cut by a rock channel tens of Ackert, R.P., Jr. 1990. Surficial geology and stratigraphy in Njord Valley, meters deep which commences in a cliff at the actual divide. western Asgard Range, Antarctica: implications for late Tertiary glacial history. This implies movement of meltwater across the mountains. A (Master of science thesis, University of Maine, Orono, Maine.) Augustinus, P.C., and M.J. Selby. 1990. Rock slope development in third argument concerns the links between Sessrumir Valley McMurdo Oasis, Antarctica, and implications for interpretations of and the valley immediately to the east. The channel system glacial history. Geografiska Annaler, 72A, 1, 55-62. crosses from the former to the latter. This is a pattern pointing Denton, G.H., T.B. Kellogg, and M.L. Prentice. 1983. Ice sheet ov- 1990 REVIEW 57 erriding of the Transantarctic Mountains. Antarctic Journal of the U.S., Sugden, D.E., and B.S. John. 1976. Glaciers and landscape. New York: 18, 93-94. Arnold. Denton, G.H., M.L. Prentice, D.E. Kellogg, and T.B. Kellogg. 1984. Sharp, M., C. Gemmell, and J-L Tison. 1989. Structure and stability Late Tertiary history of the Antarctic ice sheet: Evidence from the of the former subglacial drainage system of the Glacier de Tsan- Dry Valleys. Geology, 12, 263-267. fleuron, Switzerland. Earth Surface Processes and Landforms, 14, 119- Selby, M.J. 1986. The evidence of Miocene ice sheet overriding of the 134. Transantarctic Mountains. An agnostic view. New Zealand Antarctic Shreve, R.L. 1972. Movement of water in glaciers. Journal of Glaciology, Record, 11(62), 205-214. 11, 205-214. 58 ANTARCTIC JOURNAL.
Load more

Recommended publications
  • Management Plan For
    Measure 8 (2013) Annex Management Plan for Antarctic Specially Protected Area (ASPA) No.138 Linnaeus Terrace, Asgard Range, Victoria Land Introduction Linnaeus Terrace is an elevated bench of weathered Beacon Sandstone located at the western end of the Asgard Range, 1.5km north of Oliver Peak, at 161° 05.0' E 77° 35.8' S,. The terrace is ~ 1.5 km in length by ~1 km in width at an elevation of about 1600m. Linnaeus Terrace is one of the richest known localities for the cryptoendolithic communities that colonize the Beacon Sandstone. The sandstones also exhibit rare physical and biological weathering structures, as well as trace fossils. The excellent examples of cryptoendolithic communities are of outstanding scientific value, and are the subject of some of the most detailed Antarctic cryptoendolithic descriptions. The site is vulnerable to disturbance by trampling and sampling, and is sensitive to the importation of non-native plant, animal or microbial species and requires long-term special protection. Linnaeus Terrace was originally designated as Site of Special Scientific Interest (SSSI) No. 19 through Recommendation XIII-8 (1985) after a proposal by the United States of America. The SSSI expiry date was extended by Resolution 7 (1995), and the Management Plan was adopted in Annex V format through Measure 1 (1996). The site was renamed and renumbered as ASPA No 138 by Decision 1 (2002). The Management Plan was updated through Measure 10 (2008) to include additional provisions to reduce the risk of non-native species introductions into the Area. The Area is situated in Environment S – McMurdo – South Victoria Land Geologic based on the Environmental Domains Analysis for Antarctica and in Region 9 – South Victoria Land based on the Antarctic Conservation Biogeographic Regions.
    [Show full text]
  • University Microfilms, a XEROX Company, Ann Arbor, Michigan
    I I 72-15,173 BEHLING, Robert Edward, 1941- PEDOLOGICAL DEVELOPMENT ON MORAINES OF THE MESERVE GLACIER, ANTARCTICA. The Ohio State University in cooperation with Miami (Ohio) University, Ph.D., 1971 Geology University Microfilms,A XEROX Company , Ann Arbor, Michigan PEDOLOGICAL DEVELOPMENT ON MORAINES OF THE MESERVE GLACIER, ANTARCTICA DISSERTATION Presented In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Robert E. Behling, B.Sc., M*Sc. ***** The Ohio State University 1971 Approved by Adv Department f Geology PLEASE NOTE: Some pages have indistinct print. Filmed as received. University Microfilms, A Xerox Education Company ACKNOWLEDGEMENTS This study could not have been possible without the cooperation of faculty members of the departments of agronomy, mineralogy, and geology, I wish to thank Dr. R. P. Goldthwait as chairman of my committee, Dr. L. P. Wilding and Dr. R. T. Tettenhorst as members of my reading committee, as well as Dr. C. B. Bull and Dr. K. R. Everett for valuable assistance and criticism of the manuscript. A special thanks is due Dr. K. R. Everett for guidance during that first field season, and to Dr. F. Ugolini who first introduced me to the problems of weathering in cold deserts. Numerous people contributed to this end result through endless discussions: Dr. Lois Jones and Dr. P. Calkin receive special thanks, as do Dr. G. Holdsworth and Maurice McSaveney. Laboratory assistance was given by Mr. Paul Mayewski and R. W. Behling. Field logistic support in Antarctica was supplied by the U.S.
    [Show full text]
  • Bulletin Vol. 13 No. 6 June 1994 Voilodvlnv Antarctic Vol
    aniamcik Bulletin Vol. 13 No. 6 June 1994 VOIlOdVlNV Antarctic Vol. 13 No. 6 Issue No. 149 June 1994 Contents Polar New Zealand 226 Australia 238 France 240, 263 ANTARCTIC is published Germany 246 United Kingdom 249 quarterly by the New Zealand United States 252 Antarctic Society Inc., 1979 ISSN 0003-5327 Sub Antarctic See France Editor: Robin Ormerod Please address all editorial General inquiries, contributions etc to the: Editor, P.O. Box 2110, Able restored 269 Wellington N.Z. Antarctic Heritage Trusts 268 Telephone: (04) 4791.226 Antarctic Treaty 262 International: + 64 4 + 4791.226 Cape Roberts deferred 229 Fax: (04) 4791.185 Last dogs leave 249 International: + 64 4 + 4791.185 Emperors of Antarctica 264 Lockheed Contract 231 All NZ administrative enquiries Vanda Station 232 should go to the: National Secretary, P O. Box Obituaries 404, Christchurch All overseas administrative Dr Trevor Hatherton 271 enquiries should go to the: Overseas Secretary, P.O. Box Books 2110, Wellington, NZ Mind over Matter 274 Inquiries regarding back issues of Shadows over wasteland 276 Antarctic to P.O. Box 16485, Christchurch Cover: En route to the Emperor pen guin colony at Cape Crozier April 1992. \C) No part of this publication may be produced in any way without the prior permis sion of the publishers. Photo: Max Quinn ANTARCTIC June 1994 Vol.13 No. 6 New Zealand Successful airdrop breaks winter routine for 11 New Zealanders The midwinter airdrop took place in good conditions as scheduled on Tuesday June 21 and Thursday June 23. Each flight was undertaken by a Starlifter, refuelled en route by KC10 Extender, and crewed by up to 28 members from the selected team, some of whom came from 62nd Group McCord Airbase in the US.
    [Show full text]
  • Glaciers in Equilibrium, Mcmurdo Dry Valleys, Antarctica
    Portland State University PDXScholar Geology Faculty Publications and Presentations Geology 10-2016 Glaciers in Equilibrium, McMurdo Dry Valleys, Antarctica Andrew G. Fountain Portland State University, [email protected] Hassan J. Basagic Portland State University, [email protected] Spencer Niebuhr University of Minnesota - Twin Cities Follow this and additional works at: https://pdxscholar.library.pdx.edu/geology_fac Part of the Glaciology Commons Let us know how access to this document benefits ou.y Citation Details FOUNTAIN, A.G., BASAGIC, H.J. and NIEBUHR, S. (2016) Glaciers in equilibrium, McMurdo Dry Valleys, Antarctica, Journal of Glaciology, pp. 1–14. This Article is brought to you for free and open access. It has been accepted for inclusion in Geology Faculty Publications and Presentations by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. Journal of Glaciology (2016), Page 1 of 14 doi: 10.1017/jog.2016.86 © The Author(s) 2016. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons. org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Glaciers in equilibrium, McMurdo Dry Valleys, Antarctica ANDREW G. FOUNTAIN,1 HASSAN J. BASAGIC IV,1 SPENCER NIEBUHR2 1Department of Geology, Portland State University, Portland, OR 97201, USA 2Polar Geospatial Center, University of Minnesota, St. Paul, MN 55108, USA Correspondence: Andrew G. Fountain <[email protected]> ABSTRACT. The McMurdo Dry Valleys are a cold, dry polar desert and the alpine glaciers therein exhibit small annual and seasonal mass balances, often <±0.06 m w.e.
    [Show full text]
  • Research Commons at The
    http://waikato.researchgateway.ac.nz/ Research Commons at the University of Waikato Copyright Statement: The digital copy of this thesis is protected by the Copyright Act 1994 (New Zealand). The thesis may be consulted by you, provided you comply with the provisions of the Act and the following conditions of use: Any use you make of these documents or images must be for research or private study purposes only, and you may not make them available to any other person. Authors control the copyright of their thesis. You will recognise the author’s right to be identified as the author of the thesis, and due acknowledgement will be made to the author where appropriate. You will obtain the author’s permission before publishing any material from the thesis. PHYLOGEOGRPAHY AND GENETIC DIVERSITY OF TERRESTRIAL ARTHROPODS FROM THE ROSS DEPENDENCY, ANTARCTICA A thesis submitted in partial fulfillment of the requirements of Master of Science in Biology in Biological Sciences at The University of Waikato by Nicholas J. Demetras ____________________________________ 2010 ABSTRACT The pattern of genetic diversity in many species observed today can be traced back to historic ecological events that influenced the distribution of species not only on a global but also a local scale. For example, historical events such as habitat fragmentation, divergence in isolation, and subsequent range expansion, can result in a recognisable pattern of genetic variation which can be used to infer ecological factors (e.g. effective population size, dispersal capacity), as well as those affecting speciation processes. This thesis examines these issues from a phylogeographic and phylogenetic perspective by analysing patterns of variation in the mtDNA cytochrome c oxidase sub-unit 1 (COI) gene in two co-occurring Antarctic endemic arthropods in Southern Victoria Land, Ross Dependency.
    [Show full text]
  • Surficial Geology of Sessrumir Valley, Western Asgard Range, Antarctica
    Surficial geology and internal weathering characteristics, lithologic and volcanic of Sessrumir Valley, western ash constituents, and process-related features (i.e., glacially molded and striated clasts, extensive bedding, fissility, and Asgard Range, Antarctica: ventifacted clasts). Figure 1 shows the main features associated Implications for late with each map unit. Alpine drift is a coarse-grained, dolerite-rich deposit with Tertiary ice-sheet overriding well-developed patterned ground that occurs adjacent to a small alpine glacier in upper Sessrumir Valley (figure 2). This drift, derived entirely from local bedrock, forms arcuate lobes DAVID R. MARCHANT that parallel the alpine glacier front. Campbell and Claridge (1978, 1987) recognized three separate phases of alpine drift. Department of Geological Sciences On the basis of soil development and surface morphology, and they assigned the oldest drift to soil weathering stage 3. In the Institute for Quaternary Studies McMurdo Sound region, soils exhibiting stage 3 weathering University of Maine profiles range back to 0.5-2.1 million years (Campbell and Orono, Maine 04469 Claridge 1975). and Department of Geography Asgard till is a silt-rich, unconsolidated deposit that occurs University of Edinburgh in lower and central Sessrumir Valley. It contains granite er- Edinburgh, Scotland ratics, striated clasts, and gravel ventifacts. Asgard till, which represents an expanded tongue of the east antarctic ice sheet that filled Wright Valley (Ackert 1990), projects into mouths GEORGE H. DENTON of several north-facing cirque valleys in the western Asgard Range. Department of Geological Sciences Asgard till is poorly dated. Several lines of evidence, how- and ever, all suggest a Pliocene age.
    [Show full text]
  • Dynamics and Mass Balance of Taylor Glacier, Antarctica: 1
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114, F04010, doi:10.1029/2009JF001309, 2009 Dynamics and mass balance of Taylor Glacier, Antarctica: 1. Geometry and surface velocities J. L. Kavanaugh,1 K. M. Cuffey,2 D. L. Morse,3 H. Conway,4 and E. Rignot5 Received 15 March 2009; revised 14 June 2009; accepted 7 July 2009; published 3 November 2009. [1] Taylor Glacier, Antarctica, exemplifies a little-studied type of outlet glacier, one that flows slowly through a region of rugged topography and dry climate. This glacier, in addition, connects the East Antarctic Ice Sheet with the McMurdo Dry Valleys, a region much studied for geomorphology, paleoclimate, and ecology. Here we report extensive new measurements of surface velocities, ice thicknesses, and surface elevations, acquired with InSAR, GPS, and GPR. The latter two were used to construct elevation models of the glacier’s surface and bed. Ice velocities in 2002–2004 closely matched those in 2000 and the mid-1970s, indicating negligible interannual variations of flow. Comparing velocities with bed elevations shows that, along much of the glacier, flow concentrates in a narrow axis of relatively fast flowing ice that overlies a bedrock trough. The flow of the glacier over major undulations in its bed can be regarded as a ‘‘cascade’’; it speeds up over bedrock highs and through valley narrows and slows down over deep basins and in wide spots. This pattern is an expected consequence of mass conservation for a glacier near steady state. Neither theory nor data from this Taylor Glacier study support the alternative view, recently proposed, that an outlet glacier of this type trickles slowly over bedrock highs and flows fastest over deep basins.
    [Show full text]
  • Major Middle Miocene Global Climate Change: Evidence from East Antarctica and the Transantarctic Mountains
    Major middle Miocene global climate change: Evidence from East Antarctica and the Transantarctic Mountains A.R. Lewis† D.R. Marchant Department of Earth Sciences, Boston University, Boston, Massachusetts 02215, USA A.C. Ashworth Department of Geosciences, North Dakota State University, Fargo, North Dakota 58105, USA S.R. Hemming M.L. Machlus Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA ABSTRACT Keywords: alpine glaciers, geomorphology, understanding the full role of the Antarctic cryo- Dry Valleys, Miocene, till, volcanic ash, Antarc- sphere in this global climate event. Compari- We present a glacial record from the west- tica, Olympus Range, cold-based glaciers. son of this new glacial record to high-latitude ern Olympus Range, East Antarctica, that records elsewhere on the continent (e.g., Roc- documents a permanent shift in the thermal INTRODUCTION chi et al., 2006) and to offshore marine records regime of local glaciers, from wet- to cold- (e.g., Shevenell et al., 2004) will help establish based regimes, more than 13.94 m.y. ago. The Antarctic cryosphere prior to late Neo- the time-transgressive nature of the middle Mio- This glacial record provides the fi rst terres- gene time was substantially different from that cene climate transition and defi ne its role in trial evidence linking middle Miocene global of today. The volume of the East Antarctic Ice altering landscape development in mountainous climate cooling to a permanent reorganiza- Sheet varied signifi cantly over time scales as regions of Antarctica (e.g., Hicock et al., 2003; tion of the Antarctic cryosphere and to subse- short as 100 k.y.
    [Show full text]
  • ARCHIVED-CARN Vol 24, Nov 2007 [PDF-2.77
    Vol 24, November 2007 NEWSLETTER FOR THE Canadian Antarctic Research Network Inside Measuring Crustal Motion in Antarctica: Measuring Crustal Motion GPS, Tectonics, and Glacio-isostatic Adjustment in Antarctica: Thomas James GPS, Tectonics, and Glacio-isostatic Adjustment 1 For five weeks in early 2006, I joined the U.S. National Science Foundation’s (NSF) field team of the Transantarctic Mountain Deformation (TAMDEF) pro- RUGBY ject (www.geology.ohio-state.edu/tamdef/) measuring crustal motion in the (Research on Ultraviolet and Global warming effects Transantarctic Mountains near McMurdo Station (Fig. 1). My initial involvement on Biological pump Yields) 8 in this was as a modeller of the crustal motions expected from past and present changes in the Antarctic ice sheet. By observing and modelling these motions, Canadians in Antarctic known as glacio-isostatic adjustment (GIA), we learn about the structure and Place-Names: properties of the Earth beneath the TAMDEF region, and may possibly discern Supplement 13 new features of the ice-sheet history. In turn, well-constrained GIA models allow better interpretation of remote-sensing data to determine the mass balance of Protocol for Canada–Argentina ice sheets and the contribution that ice sheets make to sea-level change. Collaboration 16 The Transantarctic Mountains are adjacent to the West Antarctic Rift Sys- tem, a broad zone which has experienced significant extension in the past. When Canadian Involvement TAMDEF started, an issue in global tectonics was whether West Antarctica and in Antarctic Tourism Research: East Antarctica were moving relative to one another, or whether the continent an update on some moves as a relatively rigid block.
    [Show full text]
  • Linnaeus Terrace, Asgard Range, Victoria Land
    MEASURE 10 - ANNEX Management Plan for Antarctic Specially Protected Area No 138 LINNAEUS TERRACE, ASGARD RANGE, VICTORIA LAND 1. Description of values to be protected Linnaeus Terrace was originally designated in Recommendation XIII-8 (1985, SSSI No 19) after a proposal by the United States of America on the grounds that the Area is one of the richest known localities for the cryptoendolithic communities that colonize the Beacon Sandstone. Exposed surfaces of the Beacon Sandstone are the habitat of cryptoendolithic microorganisms, which may colonize a zone of up to 10 millimeters deep below the surface of the rocks. The sandstones exhibit a range of biological and physical weathering forms, as well as trace fossils, and many of the formations are fragile and vulnerable to disturbance and destruction by trampling and sampling. Cryptoendolithic communities are known to develop over time periods in the order of tens of thousands of years, and damaged rock surfaces would be slow to recolonize. The excellent examples of these communities found at the site are the subject of the original detailed Antarctic cryptoendolithic descriptions. As such, Linnaeus Terrace is considered a type locality with outstanding scientific values related to this ecosystem. These values, as well as the vulnerability of the site to disturbance and destruction, require that it receives long-term special protection. The Management Plan has been updated to include additional provisions to reduce the risk of alien plants, animals or microbes from other Antarctic sites,
    [Show full text]
  • Diabase Sheets of the Taylor Glacier Region Victoria Land, Antarctica
    Diabase Sheets of the Taylor Glacier Region Victoria Land, Antarctica GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-B Work done in cooperation with the National Science Foundation Diabase Sheets of the Taylor Glacier Region Victoria Land, Antarctica By WARREN HAMILTON With sections on PETROGRAPHY By WARREN HAMILTON, PHILIP T. HAYES, and RONALD CALVERT And sections on CHEMISTRY By WARREN HAMILTON, VERTIE C. SMITH, PAUL S. D. ELMORE, PAUL R. BARNETT, and NANCY CONKLIN CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-B Work done in cooperation with the National Science Foundation UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Page Abstract______________________________ Bl Petrology of basement sill Continued Introduction. _________________________ 2 Major oxides, by Warren Hamilton, Vertie C. Smith, Location________________________ 2 and Paul S. D. Elmore________________ B37 Present work______________________ 2 Bulk composition_______________________________ 41 Acknowledgments. _______________ 4 Minor elements, by Warren Hamilton, Paul R. Other studies...___________________ 4 Barnett, Vertie C. Smith, and Nancy M. Conklin. 42 Regional setting.__________________ 4 Density-_-___-__---_---_______________________ 45 Geography.._ _________________ 5 Differentiation. ________________________________ 46 Geology. __ ______ _ 6 Petrology of other diabase sheets.____________________ 49 Beacon Sandstone. ________ 7 Petrography, by Warren Hamilton and Philip T. Basement rocks__________ 7 Hayes----_-_-----_---_-__________-___--____- 49 Form of diabase sheets.________________ 7 Chemistry, by Warren Hamilton, Vertie C. Smith, Sheets in Beacon Sandstone. _.____-_ 7 and Paul S.
    [Show full text]
  • Decadal Topographic Change in the Mcmurdo Dry Valleys of Antarctica
    Geomorphology 323 (2018) 80–97 Contents lists available at ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph Decadal topographic change in the McMurdo Dry Valleys of Antarctica: Thermokarst subsidence, glacier thinning, and transfer of water storage from the cryosphere to the hydrosphere J.S. Levy a,⁎, A.G. Fountain b,M.K.Obrykc, J. Telling d,C.Glennied, R. Pettersson e,M.Goosefff,D.J.VanHorng a Department of Geology, Colgate University, 13 Oak Ave., Hamilton, NY 13346, USA b Department of Geology, Portland State University, Portland, OR 97201, USA c U.S. Geological Survey Cascades Volcano Observatory, Vancouver, WA 98683, USA d National Center for Airborne Laser Mapping, Department of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, USA e Department of Earth Sciences, Uppsala University, Geocentrum, Villav. 16, 752 36 Uppsala, Sweden f Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80303, USA g Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA article info abstract Article history: Recent local-scale observations of glaciers, streams, and soil surfaces in the McMurdo Dry Valleys of Antarctica Received 29 May 2018 (MDV) have documented evidence for rapid ice loss, glacial thinning, and ground surface subsidence associated Received in revised form 9 September 2018 with melting of ground ice. To evaluate the extent, magnitude, and location of decadal-scale landscape change in Accepted 10 September 2018 the MDV, we collected airborne lidar elevation data in 2014–2015 and compared these data to a 2001–2002 air- Available online 13 September 2018 borne lidar campaign.
    [Show full text]