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Volumn 299, Issue 5603, 2003, Pages 99-102

Holocene deglaciation of Marie Byrd Land, West Antarctica

Author keywords

[No Author keywords available]

Indexed keywords

COASTAL ZONES; ICE; MELTING;

EID: 0037414842     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.1077998     Document Type: Article
Times cited : (212)

References (45)
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    • note
    • The larger size, higher elevation, and more continental setting of the East Antarctic Ice Sheet retard its response to changes in climate and sea level.
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    • note
    • 10Be and diatom microfossils of Quaternary age in sediment cores from beneath Whillans Ice Stream (formerly "ice stream B"). They interpret these results to indicate that the interior Ross Embayment was an open marine basin at least once since 750,000 years B.P.
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    • 10Be data are available as supporting material on Science Online.
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    • note
    • Ages reflect cumulative exposure to cosmic radiation. Rocks from glacial deposits can give anomalously old ages if they are recycled from older deposits or derived from an exposed source area such as a mountainside or talus slope. Other conditions, such as snow cover, delayed emergence after deposition deep within a moraine, or disturbance by frost heaving, can produce anomalously young ages. We avoided sites and samples prone to snow or sediment cover or to periglacial disturbance. We therefore regard the young ages as reliable and attribute the old "ages" to previous exposure.
  • 19
    • 0348205694 scopus 로고    scopus 로고
    • note
    • Reconstructing the surface slope and elevation of the Boyd Glacier from transects on Mount Darling, Mount Blades, and Mount Rea (fig. 51) shows that a cluster of ∼1100-m peaks in the eastern Sarnoff Mountains may have stood above the LGM ice surface. We examined these peaks but found no glacial deposits on them. Either flow lines terminating on their flanks did not connect with debris sources upstream or the peaks were capped during the LGM by a small local ice dome flowing outward.
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    • R. B. Alley, R. A. Bindschadler, Eds. (American Geophysical Union, Washington, DC)
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    • unpublished data
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    • note
    • Antarctic ice cores record substantially higher snow accumulation rates in the Holocene than during the LGM. Accumulation doubled at Vostok and Dome C, and increased by factors of 2.5 and 4 to 5 at Byrd Station and Taylor Dome, respectively. It appears that coastal sites experienced the greatest contrasts, supporting the idea that increased accumulation contributed to delayed deglaciation in Marie Byrd Land.
  • 27
    • 0346314904 scopus 로고    scopus 로고
    • note
    • Interpretation of very recent changes in glacier height is complicated by ice fields skirting many of the peaks. Erratics must have been transported and deposited by glaciers ablating against the mountain sides, requiring flow driven by surface gradients sloping toward the mountains. Most peaks are now surrounded by ice fields sloping outward. Our estimates of thinning depend on whether the erratics emerged from beneath through-flowing glacier ice at a time when the glaciers abutted the peaks directly or after the present pattern of skirting ice fields developed. In the first case, glacier axes must have stood higher than the erratics at the time of deglaciation. In the latter case, the elevations of the glacier axes may not have changed much since deglaciation. Although this makes it difficult to resolve very recent changes, it is a minor consideration for samples located hundreds of meters above the modern glaciers.
  • 35
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    • note
    • Far from the ice sheets, relative sea level changes (i.e., changes in the relative height of land and sea causing coastlines to move landward or seaward) are strongly influenced by hydro-isostasy, a deepening of the ocean basins and tilting of continental margins in response to loading by meltwater. Modeled sea level changes in Africa, Australia, and other far-field sites assuming synchronous melting of ice sheets predict greater falls in relative sea level (∼4 to 5 m) since 7000 years B.P. than those observed (1 to 3 m). The explanation for the difference, invoked by Nakada and Lambeck (34) but not substantiated until the recent discovery of late WAIS deglaciation, is continued meltwater addition to the oceans since 7000 years B.P.
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    • note
    • 3 (LGM to present) corresponds to ∼1.4 m of esl, of which ∼0.4 m would have been released since 10,000 years B.P. Glacier profiles interpolated between our elevation transects suggest that more than half of this volume (∼0.2 to 0.3 m of esl) was released after 7000 years B.P. (fig. S1).
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    • cited 4 December 2002
    • Scientific Committee on Antarctic Research, Antarctic Digital Database, Version 4.0 [cited 4 December 2002]; available at www.nerc-bas.ac.uk/ public/magic/add_main.html.
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    • note
    • This work was supported by NSF grants DPP-9909778 and DPP-9615282. We thank the staff of the U.S. Antarctic Program and M. Roberts and C. Kugelman for help with all aspects of the fieldwork, C. Kumick and B. Johns of UNAVCO, Inc. for high-precision Global Positioning System measurements, and K. Lambeck and T. Purcell for assistance with ice-volume calculations. P. Apostle, K. Krigbaum, and D. Carrasco contributed to the laboratory work.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.