The Dominion Range Ice Core, Queen Maud Mountains, Antarctica - General Site and Core Characteristics with Implications
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The University of Maine DigitalCommons@UMaine Earth Science Faculty Scholarship Earth Sciences 1990 The ominionD Range Ice Core, Queen Maud Mountains, Antarctica—General Site and Core Characteristics with Implications Paul Andrew Mayewski University of Maine, [email protected] Mark S. Twickler William Berry Lyons Mary Jo Spencer Debra A. Meese See next page for additional authors Follow this and additional works at: https://digitalcommons.library.umaine.edu/ers_facpub Part of the Glaciology Commons, and the Hydrology Commons Repository Citation Mayewski, Paul Andrew; Twickler, Mark S.; Lyons, William Berry; Spencer, Mary Jo; Meese, Debra A.; Gow, Anthony J.; Grootes, Pieter; Sowers, Todd; Watson, M. Scott; and Saltzman, Eric, "The ominionD Range Ice Core, Queen Maud Mountains, Antarctica—General Site and Core Characteristics with Implications" (1990). Earth Science Faculty Scholarship. 264. https://digitalcommons.library.umaine.edu/ers_facpub/264 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]. Authors Paul Andrew Mayewski, Mark S. Twickler, William Berry Lyons, Mary Jo Spencer, Debra A. Meese, Anthony J. Gow, Pieter Grootes, Todd Sowers, M. Scott aW tson, and Eric Saltzman This article is available at DigitalCommons@UMaine: https://digitalcommons.library.umaine.edu/ers_facpub/264 Journal of Glaciology, Vo!. 36, No. 122, 1990 THE DOMINION RANGE ICE CORE, QUEEN MAUD MOUNTAINS, ANTARCTICA - GENERAL SITE AND CORE CHARACTERISTICS WITH IMPLICATIONS By PAUL A. MAYEWSKI, MARK S. TWICKLER, WM BERRY LYONS, MARY 10 SPENCER, (Glacier Research Group, Institute for the Study of Earth, Oceans and Space (EOS), University of New Hampshire, Durham, New Hampshire 03824, U.S.A.) DEBRA A. MEESE, (Glacier Research Group, Institute for the Study of Earth, Oceans and Space (EOS), University of New Hampshire, Durham, New Hampshire 03824, U.S.A., and U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire 03755, U.S.A.) ANTHONY 1. Gow, (U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire 03755, U.S.A.) PIETER GROOTES, (Quaternary Isotope Laboratory, University of Washington, Seattle, Washington 98195, U.S.A.) TODD SO W ERS, (Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, U.S.A.) M. SCOTT WATSON, (Polar Ice Coring Office, University of Nebraska, Lincoln, Nebraska 68558, U.S.A.) and ERIC SALTZMAN (Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, Florida 33149, U.S.A.) ABSTRACT. The Transantarctic Mountains of East they could provide some of the most climatically sensitive Antarctica provide a new milieu for retrieval of ice-core records available from Antarctica. Furthermore, unlike records. We report here on the initial findings from the those ice cores retrieved from the interior of Antarctica, first of these records, the Dominion Range ice-core record. there are terrestrial records from nearby sites that can be Sites such as the Dominion Range are valuable for the used for comparison (e.g. Denton and others, 1971; Drewry, recovery of records detailing climate change, volcanic 1980; Sruiver and others, 1981; Mayewski and Goldthwait, activity, and changes in the chemistry of the atmosphere. 1985). The unique geographic location of this site and a relatively The Dominion Range (Fig. I) is the first in a series of low accumulation rate combine to provide a relatively long planned Transantarctic Mountains ice-core sites (Fig. I). The record of change for this potentially sensitive climatic Dominion Range is located along the edge of the East region. As such, information concerning the site and general Antarctic ice sheet, approximately 500 km from the South core characteristics are presented, including ice surface, ice Pole and 120 km from the Ross Ice Sh elf, at the confluence thickness, bore-hole temperature, mean annual net accumu of Beardmore and Mill Glaciers (Fig. 2). These glaciers, lation, crystal size, crystal fabric, oxygen-isotope composi along with several other outlet glaciers in the Queen Maud tion, and examples of ice chemistry and isotopic Mountains (sub-sector of the Transantarctic Mountains), composition of trapped gases. drain the Titan Dome area of the East Antarctic ice sheet. Approximately half of the Dominion Range (Fig. 2) is ice free and the average elevation of the range is 2700 m. INTRODUCTION Between 20 November and 14 December 1984, a tent camp was operated in the Dominion Range. Due to logistic Localized accumulation basins in the Transantarctic restraints, all aspects of the study, including reconnaissance, Mountains, fed completely by precipitation on to the site, site characterization, and recovery of a 20 I m core were provide a new avenue for Anwrctic ice-core research. These undertaken in the same field season. In this paper we sites are valuable for the recovery of records detailing present the results of site and core characterization, climatic change, volcanic activity, and changes in specifically ice surface and ice thickness, bore-hole temp atmospheric chemistry for periods extending well into the erature, mean annual net accumulation, crystal size, crystal last glacial period. Since these sites are located within the fabric, oxygen-isotope composition, and examples of ice transitional zone between plateau ice and ocean-ice shelf, chemistry (C 1-, SO�-, MSA), and isotopic composition of trapped gases. II Joumal of Glaciology s.p. 85·5 ICE-SURFACE AND ICE-THICKNESS MEASUREMENTS The early part of the field season was devoted to establishing an optimum site for recovery of an ice core (Fig. 2). Maps, visual observations of ice-surface topo REEDY GLACIER/ graphy, and the presence of bedrock ridges all validated initial estimates that the Dominion Range ice cover is either entirely separated from or only minimally connected to the 80·5 East Antarctic ice sheet and hence the site is a catchment for local precipitation. Exposed bedrock ridges flanking the Dominion Range are cavernously weathered. Comparison of the degree of cavernous weathering with that examined in ROSS ICE SHELF the general region of the Queen Maud Mountains by Mayewski and Goldthwait (1985) suggests that ice has not topped these ridges for at least several tens of thousands of ...9. years. SOUTHERN VICTORIA Based on an examination of USGS (I : 250 000) LAND topographic maps and a radio echo-sounding survey conducted in the field, the Dominion Range ice mass is TAYLOR VALLEY ROSS SEA WRIGHT vALLEY divisible into three major drainage basins, referred to as A, B, and C (Fig. 2). The radio-echo survey employed a � ICE'FREE AREAS mono-pulse system (after Watts and Isherwood, 1978) and was centered primarily over drainage basin C. It included measurements at 42 stations, ten of which were occupied at least twice to test instrument reproducibility, which proved to be less than the error inherent in reading the oscilloscope. Final ice-thickness measurements were deter mined using Watts and Isherwood's (1978) relationship with adjustments for density made using measurements from the core. Crevassed areas in the southern section of basin C, lower Vandament Glacier, prevented the recovery of useful o 300 600 I I radio echo-sounding data from this area. Scale (km) Drainage basin C surface topography (Fig. 3) is characterized by a general surface slope to the east, thus Fig. 1. Locatioll map. Beardmore Glacier Glacier ® � 1.6 km • Radio Echo Soundlnq Srollon ® Ouler Limits of Radio Echo f> SoundinQ Survey • Drill Slle Ice Surface Contours Approllimote Locotlon of C·A DroinOQe Divide (see FiQure 2) Estimoted Sur/ace Flo ....lines @--(9 Vondoment Glacier Flowllne (see FiQure 2) Fig. 3. Drainage basil! C ice surface. N the major part of the drainage for C discharges through Vandament Glacier. Ice thicknesses in basin C (Fig. 4) range from �350 to <50 m with the thickest areas north of � '-----------' the drill site and in the Mount Tennant area. Thinner ice 5km areas are found in the western part of the basin close to the C-A surface ice divide, and the remainder of the basin is characterized by ice depths most commonly in the range CD Vandament Glacier Approximate Outline of 200-300 m. The general gradient of the subglacial Relatively Ice Free Terrain ® Koski Glacier topography is east-south-east. Estimated Drainage Divides @ Rutkowski Glacier The core site (see Figs 2, 3, and 4) was chosen �L7 km A,B,C Drainage Basins down-flow line from the C-A ice divide to mlOlmize Generalized Surface Flowlines complications due to flow right on the divide and �L7 km ® Mt. Tennent Drill Site up-slope from the base camp to minimize the effects of @ Kane Rocks Outer limits of Radio Echo any local chemical contamination from the camp. Although © Mt. Mills Sounding Survey it cannot be demonstrated definitively with the data @ Mt. Sanders available, it appears that if any East Antarctic ice penetrates ® Mt. Nimrod drainage basin C from the Mount Tennant area that this ice would be deflected eastward toward Vandament Glacier and hence away from the drill site. A comparison between Fig. 2. Domillioll Range locatioll map. ice-surface contours (Fig. 3) and ice-thickness contours 12 MayelVski and others: Dominion Range ice core, Alltarctica (Fig. 4) in the area of the Vandament Glacier flow line suggests that the ice in this area must be strained. BORE-HOLE TEMPERATURE AND MEAN ANNUAL NET ACC UMULATION Temperature measurements were made at 5 m intervals (Fig. 5) down the entire length of the bore hole using a thermistor system designed by L. Hansen (PICO). Twenty readings at 20 s intervals were made at each depth immediately following a 10 min equilibrium period. ° Instrument error is ±0. 02 C based on duplicate measure ments.