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
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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南极洲东泰勒谷罗斯海漂流的放射性碳年代学：末次盛冰期罗斯海有接地冰盖的证据
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
G. Denton
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文献类型：
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作者：
B. Hall;G. Denton
超过250个湖泊藻类和海洋贝壳的放射性碳测年提供了泰勒谷东部罗斯海漂流的年代学。生活在冰坝覆盖的沃什伯恩湖的藻类的年代表明，在公元前8340到23,800年间，搁浅的罗斯海冰堵塞了泰勒河谷的河口。罗斯海冰在Hjorth Hill Moraine处于12,700到14,600 14C yr BP之间的最大位置，并在10,794 14 C yr BP之前距离该位置500米范围内。这意味着，罗斯海冰盖在罗斯岛北部延伸并穿过麦克默多海峡到泰勒山谷的流线一定保持完好，因此，罗斯岛以东的搁浅冰盖一定存在到公元前834014C年。泰勒谷冰坝湖泊和麦克默多海峡贝壳的证据表明，在公元6500到8340年间，罗斯岛附近的接地线撤退了。如果这是正确的，那么西普尔海岸今天的接地线的大部分衰退发生在随后没有显著的消冰期海平面上升的情况下。海平面上升可能触发了冰盖内部的机制，导致了冰盖的消退，但本身并没有推动冰盖持续衰退。冰川一旦开始消退，就会在没有海平面压力的情况下继续下去。如果正确，这一假设意味着接地线可能会继续退回到西南极冰盖的内部蓄水池中。
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.