Evidence for the long-term sedimentary environment in an Antarctic subglacial lake
Evidence for the long-term sedimentary environment in an Antarctic subglacial lake
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DOI：
10.1016/j.epsl.2018.10.011
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发表时间：
2018-12-15
影响因子：
5.3
通讯作者：
King, Edward C.
中科院分区：
文献类型：
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作者：
Smith, Andrew M.;Woodward, John;King, Edward C.
南极冰盖下的湖泊具有重要的科学意义，因为它们能够保存冰盖历史和沉积物中微生物生命的独特记录。然而，尚未从冰盖内部获得冰下湖泊沉积的记录，并且对冰下湖泊环境中的沉积途径，过程和结构的理解仍然不确定。本文对冰下埃尔斯沃思湖的地震数据进行了分析，结果表明，湖床由非常细粒度的沉积物组成，沉积在低能量环境中，水和沉积物通量低。最小沉积厚度为6 m，是长期低沉积速率的结果。根据少数可用的类似物，我们推测该沉积物年龄范围至少为150 ka，可能为100 - 100 Ma。沉积物团块运动发生过，但很少发生，并被随后的沉积所掩埋。我们提出了一个冰下湖泊沉积的新概念模型，为评估冰下湖泊环境的过程、确定未来的湖泊通道位置和解释冰下湖泊样本提供了一个框架。(C) 2018年作者。Elsevier B.V.出版
Lakes beneath the Antarctic Ice Sheet are of fundamental scientific interest for their ability to contain unique records of ice sheet history and microbial life in their sediments. However, no records of subglacial lake sedimentation have yet been acquired from beneath the interior of the ice sheet, and understanding of sediment pathways, processes and structure in subglacial lake environments remains uncertain. Here we present an analysis of seismic data from Subglacial Lake Ellsworth, showing that the lake bed comprises very fine-grained sediments deposited in a low energy environment, with low water- and sediment-fluxes. Minimum sediment thickness is 6 m, the result of prolonged low sedimentation rates. Based on the few available analogues, we speculate this sediment age range is a minimum of 150 ka, and possibly >1 Ma. Sediment mass movements have occurred, but they are rare and have been buried by subsequent sedimentation. We present a new conceptual model of subglacial lake sedimentation, allowing a framework for evaluating processes in subglacial lake environments, and for determining future lake access locations and interpreting subglacial lake samples. (C) 2018 The Authors. Published by Elsevier B.V.