Late Wisconsin Reconstruction for the Ross Sea Region, Antarctica

Drewry, David J.

doi:10.1017/s0022143000014763

Cited by 57 publications

(24 citation statements)

References 24 publications

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“…Ice derived from high elevations on the Polar Plateau but now stranded on the McMurdo Ice Shelf, and the pattern of the Transantarctic Mountains erratics support our reconstructions of Mulock Glacier ice rounding Minna Bluff but with all ice from Skelton Glacier ablating south of the bluff. They are inconsistent with Drewry’s (1979) LGM reconstruction that includes Skelton Glacier ice in the McMurdo-Sound through-flow. Drewry’s (1979) model closely approximates our results for 12000-4000 BP.…”

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confidence: 59%

“…They are inconsistent with Drewry’s (1979) LGM reconstruction that includes Skelton Glacier ice in the McMurdo-Sound through-flow. Drewry’s (1979) model closely approximates our results for 12000-4000 BP. Ice-sheet modeling holds promise for determining whether deglaciation proceeded by grounding-line retreat of an ice sheet that was largely stagnant, because it never approached equilibrium flowline profiles after the Ross Ice Shelf grounded, or of a dynamic ice sheet with flowline profiles kept low by active ice streams that extended northward from present-day outlet glaciers after the Ross Ice Shelf grounded.…”

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confidence: 59%

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Late Pleistocene interactions of East and West Antarctic Ice-flow Regimes: evidence from the McMurdo Ice Shelf

1996

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We present new interpretations of deglaciation in McMurdo Sound and the western Ross Sea, with observationally based reconstructions of interactions between East and West Antarctic ice at the last glacial maximum (LGM), 16000, 12000, 8000 and 4000 BP. At the LGM, East Antarctic ice from Mulock Glacier split; one branch turned westward south of Ross Island but the other branch rounded Ross Island before flowing southwest into McMurdo Sound. This flow regime, constrained by an ice saddle north of Ross Island, is consistent with the reconstruction of Stuiver and others (1981a). After the LGM, grounding-line retreat was most rapid in areas with greatest water depth, especially along the Victoria Land coast. By 12000 BP, the ice-now regime in McMurdo Sound changed to through-flowing Mulock Glacier ice, with lesser contributions from Koettlitz, Blue and Ferrar Glaciers, because the former ice saddle north of Ross Island was replaced by a dome. The modern flew regime was established ∼4000 BP. Ice derived from high elevations on the Polar Plateau but now stranded on the McMurdo Ice Shelf, and the pattern of the Transantarctic Mountains erratics support our reconstructions of Mulock Glacier ice rounding Minna Bluff but with all ice from Skelton Glacier ablating south of the bluff. They are inconsistent with Drewry’s (1979) LGM reconstruction that includes Skelton Glacier ice in the McMurdo-Sound through-flow. Drewry’s (1979) model closely approximates our results for 12000-4000 BP. Ice-sheet modeling holds promise for determining whether deglaciation proceeded by grounding-line retreat of an ice sheet that was largely stagnant, because it never approached equilibrium flowline profiles after the Ross Ice Shelf grounded, or of a dynamic ice sheet with flowline profiles kept low by active ice streams that extended northward from present-day outlet glaciers after the Ross Ice Shelf grounded.

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confidence: 59%

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confidence: 59%

Late Pleistocene interactions of East and West Antarctic Ice-flow Regimes: evidence from the McMurdo Ice Shelf

1996

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“…As a result, estimates of the overall Antarctic contribution to eustatic sea-level drop at the LGM range from 0.5 to 29 m (Drewry 1979;Stuiver et al 1981;Denton et al 1989a;Huybrechts 1990;Colhoun et al 1992;Bentley 1999).…”

Section: The Problemmentioning

confidence: 99%

Evidence from taylor valley for a grounded ice sheet in the ross sea, antarctica

Hall

Denton

Hendy

2000

Geografiska Annaler: Series A, Physical Geography

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Four glacial drifts are exposed in eastern Taylor Valley and on Cape Bernacchi on the western side of McMurdo Sound, Ross Sea, Antarctica: Alpine I, Ross Sea, Wilson, and Bonney drifts. Bonney drift is the oldest, underlying Ross Sea drift near Canada Glacier. Ross Sea and Wilson drifts are contemporaneous. Alpine I drift is the youngest, overlying and commonly composed of reworked older deposits. Ross Sea drift extends to 350 m elevation at the Hjorth Hill moraine at the mouth of Taylor Valley. The slope of the moraine, as well as the areal extent of the drift, indicates that Ross Sea drift was deposited by a thick lobe of westward‐flowing ice grounded in Explorers Cove. This ice lobe blocked the mouth of Taylor Valley and dammed Glacial Lake Washburn. Relict deltas and shore‐lines extend up to 336 m elevation and mark the former level of the lake. A lake‐ice conveyor, similar to that now operating on Trough Lake 100 km south of Taylor Valley, transported Ross Sea drift from the ice lobe westward across Glacial Lake Washburn. Kenyte erratics in Ross Sea drift indicate that the ice lobe grounded in Explorers Cove was fed by ice from a flow line that extended around Cape Bird, across western Ross Island, and across McMurdo Sound before terminating in the mouth of Taylor Valley. Overall, the extent of Ross Sea drift, as well as the elevation and slope of its moraines, and the presence of kenyte erratics, all suggest that a large grounded ice sheet existed in the Ross Sea Embayment during the deposition of Ross Sea drift in Taylor Valley. This ice sheet formed during advance of the West Antarctic Ice Sheet across the Ross Sea continental shelf at the last glacial maximum and has implications for the contribution of Antarctica to global sea‐level change at that time. The areal extent of Wilson drift, as well as former ice‐flow directions inferred from striated and glacially molded bedrock, both indicate that the Wilson Piedmont Glacier deposited Wilson drift during a seaward advance over Marble and Gneiss Points. The piedmont glacier merged with the Ross Sea ice lobe on Cape Bernacchi and Hjorth Hill. Alpine I drift relates to the modern advance of alpine and outlet glaciers. Bonney drift represents an advance of Taylor Glacier during the penultimate interglaciation 70,000–120,000 yr bp.

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“…However, the extent of grounded ice in the Ross Sea Embayment has been under debate (Colhoun et al 1992). As a result, estimates of the overall Antarctic contribution to eustatic sea-level drop at the LGM range from 0.5 to 29 m (Drewry 1979;Stuiver et al 1981;Denton et al 1989a;Huybrechts 1990;Colhoun et al 1992;Bentley 1999).…”

Section: Introductionmentioning

confidence: 99%

Radiocarbon chronology of ross sea drift, eastern taylor valley, antarctica: evidence for a grounded ice sheet in the ross sea at the last glacial maximum

Hall

Denton

2000

Geografiska Annaler: Series A, Physical Geography

109

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More than 250 radiocarbon dates of lacustrine algae and marine shells afford a chronology for Ross Sea drift in eastern Taylor Valley. Dates of algae that lived in ice‐dammed Glacial Lake Washburn show that grounded Ross Sea ice blocked the mouth of Taylor Valley between 8340 and 23,800 14C yr bp. Ross Sea ice was at its maximum position at the Hjorth Hill moraine between 12,700 and 14,600 14C yr bp and was within 500m distance of this position as late as 10,794 14C yr bp. The implication is that the flow line of the Ross Sea ice sheet which extended around northern Ross Island and across McMurdo Sound to Taylor Valley must have remained intact, and hence that a grounded ice sheet must have existed east of Ross Island as late as 8340 14C yr bp. Evidence from ice‐dammed lakes in Taylor Valley and from shells from McMurdo Sound suggests grounding‐line retreat from the vicinity of Ross Island between 6500 and 8340 14C yr bp. If this is correct, then most recession to the present‐day grounding line on the Siple Coast took place subsequently in the absence of significant deglacial sea‐level rise. Rising sea level may have triggered internal mechanisms within the ice sheet that led to retreat, but did not in itself drive continued ice‐sheet recession. Ice retreat, once set in motion, continued in the absence of sea‐level forcing. If correct, this hypothesis implies that the grounding line could continue to recede into the interior reservoir of the West Antarctic Ice Sheet.

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Late Wisconsin Reconstruction for the Ross Sea Region, Antarctica

Cited by 57 publications

References 24 publications

Late Pleistocene interactions of East and West Antarctic Ice-flow Regimes: evidence from the McMurdo Ice Shelf

Late Pleistocene interactions of East and West Antarctic Ice-flow Regimes: evidence from the McMurdo Ice Shelf

Evidence from taylor valley for a grounded ice sheet in the ross sea, antarctica

Radiocarbon chronology of ross sea drift, eastern taylor valley, antarctica: evidence for a grounded ice sheet in the ross sea at the last glacial maximum

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