Holocene glacier behavior around the northern Antarctic Peninsula and possible causes
Holocene glacier behavior around the northern Antarctic Peninsula and possible causes
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DOI：
10.1016/j.epsl.2020.116077
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发表时间：
2020-03-15
影响因子：
5.3
通讯作者：
Schwartz, R.
中科院分区：
文献类型：
--
作者：
Kaplan, M. R.;Strelin, J. A.;Schwartz, R.
我们获得了49个新的Be-10年龄，记录了前北方南极半岛冰盖的活动，随后詹姆斯罗斯岛冰帽和附近的冰川，从末次冰期结束，直到最后一个类似100年。研究表明，从>11 ~ 8 ka，詹姆斯罗斯岛周围冰川系统（包括冰川和陆地终端冰川）发生了明显的衰退。冰川在8-7 ka时到达海湾和峡湾的顶端。随后，当地的冰川比现在大（至少）7.5-7 ka和类似于5-4 ka，在3.9和3.6 ka之间和3 ka之后，在类似于2.4和类似于1 ka之间，从类似于300到类似于100年前。冰消期后，最大的局部冰川范围发生在近似7 ka和近似4ka之间。与其他古气候记录，包括海冰范围的比较，揭示了一致的气候变化，在近似15度的纬度。在全新世早期，大部分时间里，从南美洲南部到南极半岛地区都有一条温暖的地带。我们推断这样的时间间隔是减弱和/或向极扩展的带较强的西风带，与极涡的收缩。相反，增加海冰和赤道扩张的西风带和极地涡旋有利于较大的冰川从巴塔哥尼亚到南极半岛，这通常发生在类似的8 ka后，虽然温暖的伸展没有发生。例如，在南极半岛和巴塔哥尼亚，从4到近似3 ka的时间间隔通常是温暖的，但两个地区的条件并不一致。我们还推断，减少和扩大巴塔哥尼亚和南极半岛东部的冰川范围往往会发生时，条件类似于一个持续的积极和消极的南部环形模式，分别。(C)2020爱思唯尔B. V.保留所有权利。
We obtained 49 new Be-10 ages that document the activity of the former Northern Antarctic Peninsula Ice Sheet, and subsequently the James Ross Island Ice Cap and nearby glaciers, from the end of the last glacial period until the last similar to 100 years. The data indicate that from >11 to similar to 8 ka marked recession of glacier systems occurred around James Ross Island, including tidewater and local land-terminating glaciers. Glaciers reached heads of bays and fjords by 8-7 ka. Subsequently, local glaciers were larger than present around (at least) 7.5-7 ka and similar to 5-4 ka, at times between 3.9 and 3.6 ka and just after 3 ka, between similar to 2.4 and similar to 1 ka, and from similar to 300 to similar to 100 years ago. After deglaciation, the largest local glacier extents occurred between similar to 7 ka and similar to 4 ka.Comparison with other paleoclimate records, including of sea ice extent, reveals coherent climate changes over similar to 15 degrees of latitude. In the early Holocene, most of the time a swath of warmth spanned from southern South America to the Antarctic Peninsula sector. We infer such intervals are times of weakening and/or poleward expansion of the band of stronger westerlies, associated with contraction of the polar vortex. Conversely, increased sea ice and equatorward expansion of the westerlies and the polar vortex favor larger glaciers from Patagonia to the Antarctic Peninsula, which typically occurred after similar to 8 ka, although warm stretches did take place. For example, on the Antarctic Peninsula and in Patagonia the interval from 4 to similar to 3 ka was typically warm, but conditions were not uniform in either region. We also infer that reduced and expanded glacier extents in Patagonia and the eastern Antarctic Peninsula tend to occur when conditions resemble a persistent positive and negative southern annular mode, respectively. (C) 2020 Elsevier B.V. All rights reserved.