Late Quaternary Glacial History of George VI Sound Area, West Antarctica
Late Quaternary Glacial History of George VI Sound Area, West Antarctica
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南极洲西部乔治六世海峡地区的晚第四纪冰川历史
DOI：
10.1016/0033-5894(82)90074-6
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发表时间：
1982
影响因子：
2.3
通讯作者：
D. Sugden
中科院分区：
文献类型：
--
作者：
C. Clapperton;D. Sugden
在南极洲西部的最后一次盛冰期期间，亚历山大岛和帕尔默地形成了独立的冰盖，在乔治六世海峡汇合，并从南纬 72° 向北排放。对基底中发现的贝壳碎片（Hiatella Solida）进行放射性碳（>32,000 年）和氨基酸（约 120,000 年）年龄测定，表明该冰川作用的威斯康星年龄他们。冰流模式与 CLIMAP 重建中针对该区域推断的冰流模式不同。在最大阶段之后，当出口山谷冰川从较小的冰盖流入乔治六世海峡时，发生了一次体育场事件。更广泛的衰退使得乔治六世冰架在亚历山大岛东部沉积了帕尔默地不稳定物，然后均衡恢复将其最终升高到约 82 m 的高度。大约距今 6500 年，冰架可能已经不存在，当时海峡中生活着大型藤壶（Bathylasma corolliforme）。在冰架重新形成并将藤壶壳纳入亚历山大岛的冰碛之前，小冰川重新推进，形成至少两个终端冰碛。这些贝壳的 14C 年龄（针对南极条件进行校正）约为距今 6500 年。以及与全新世年龄一致的氨基酸比例。在山谷冰川和冰架的振荡导致形成目前连续的冰芯冰碛序列之前，山谷冰川重新移过冰架冰碛，可能是在小冰河时期。这种振荡可能代表了在维多利亚地的干燥山谷中尚未观察到的气候控制，维多利亚地是南极洲唯一对冰川波动进行详细研究的其他地区。
During the last glacial maximum in West Antarctica separate ice caps developed on Alexander Island and on Palmer Land, became confluent in George VI Sound, and discharged northward from latitude 72° S. Radiocarbon (>32,000 yr) and amino acid (approximately 120,000 yr) age determinations on shell fragments (Hiatella solida) found in basal till suggest a Wisconsin age for the glaciation that incorporated them. The pattern of ice flow differed from that deduced for this area in the CLIMAP reconstruction. Following the maximum stage, there was a stadial event when outlet valley glaciers flowed from smaller ice caps into George VI Sound. More widespread recession permitted the George VI ice shelf to deposit Palmer Land erratics on eastern Alexander Island before isostatic recovery raised them to final elevations of about 82 m. The ice shelf may have been absent at about 6500 yr B.P., when large barnacles (Bathylasma corolliforme) were living in the sound. Small glaciers readvanced to form at least two terminal moraines before the ice shelf re-formed and incorporated the barnacle shells into its moraine on Alexander Island. The shells gave a 14C age (corrected for Antarctic conditions) of about 6500 yr B.P. and an amino acid ratio consistent with a Holocene age. Valley glaciers readvanced over the ice-shelf moraine before oscillations of both valley glaciers and the ice shelf led to the formation of the present sequence of contiguous ice-cored moraines, probably during the Little Ice Age. Such oscillations may represent a climatic control not yet observed in the dry valleys of Victoria Land, the only other part of Antarctica studied in detail for glacier fluctuations.