Meltwater intensive glacial retreat in polar environments and investigation of associated sediments: example from Pine Island Bay, West Antarctica
Meltwater intensive glacial retreat in polar environments and investigation of associated sediments: example from Pine Island Bay, West Antarctica
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极地环境中融水密集的冰川退缩和相关沉积物的调查：来自西南极洲松岛湾的例子
DOI：
10.1016/j.quascirev.2013.11.021
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发表时间：
2014
影响因子：
4
通讯作者：
M. Jakobsson
中科院分区：
文献类型：
--
作者：
Alexandra E. Witus;C. Branecky;John B. Anderson;W. Szczuciński;D. Schroeder;D. Blankenship;M. Jakobsson
现代松岛冰川和斯韦茨冰川都流入松岛湾，它们是南极冰冻圈变化最快的部分，也是南极最不稳定的冰流。在这里，我们表明，松树岛湾最上面的沉积物单元是在冰盖退缩的后期（7-8.6 k cal yr BP）由融水羽流沉积的，并认为该沉积物记录了融水密集沉积的事件。plumite是一种水力分选的冰川来源的悬垂矿床，覆盖在近冰川期沉积物上，并向现代接地线方向加厚。最上面的沉积物单元被解释为非稳态过程的产物，在这种过程中，大型基岩盆地的低背景沉积与这些盆地中含沙水的间歇冲刷交替发生。松岛湾的内部包含几个由水道连接的盆地，这些盆地的蓄水量约为70平方公里，泥沙蓄积量很大。这些盆地的冲刷是由水势变化和冰川重组引起的。经这些过程调动的泥沙总量为120 km2。该研究表明，全新世以来，松岛湾的融水密集沉积至少发生过三次。最近的事件与历史上接地线的快速后退相吻合，相对于整个装置的流量大了一个数量级。我们注意到玛格丽特湾冰流退缩的最后阶段以类似的沉积事件为标志，并表明现代思韦茨冰川正处于类似的融水密集退缩阶段。
Modern Pine Island and Thwaites Glaciers, which both drain into Pine Island Bay, are among the fastest changing portions of the cryosphere and the least stable ice streams in Antarctica. Here we show that the uppermost sediment unit in Pine Island Bay was deposited from a meltwater plume, a plumite, during the late stages of ice sheet retreat ∼7–8.6 k cal yr BP and argue that this deposit records episodes of meltwater intensive sedimentation.The plumite is a hydraulically sorted, glacially sourced, draping deposit that overlies proximal glacimarine sediments and thickens towards the modern grounding line. The uppermost sediment unit is interpreted as a product of non-steady-state processes in which low background sedimentation in large bedrock-carved basins alternates with episodic purging of sediment-laden water from these basins. The inner part of Pine Island Bay contains several basins that are linked by channels with a storage capacity on the order of 70 km3of stagnant water and significant sediment storage capacity. Purging of these basins is caused by changes in hydraulic potential and glacial reorganization. The sediment mobilized by these processes is found here to total 120 km3.This study demonstrates that episodes of meltwater-intensive sedimentation in Pine Island Bay occurred at least three times in the Holocene. The most recent episode coincides with rapid retreat of the grounding line in historical time and has an order of magnitude greater flux relative to the entire unit. We note that the final phase of ice stream retreat in Marguerite Bay was marked by a similar sedimentary event and suggest that the modern Thwaites Glacier is poised for an analogous meltwater-intensive phase of retreat.
影响因子：
18.3
作者：
Rignot, Eric;Bamber, Jonathan L.;Van Meijgaard, Erik
通讯作者：
Van Meijgaard, Erik
南极洲西部阿蒙森海海湾近期沉积物和冰期沉积物之间的物源变化：粘土矿物组合证据
影响因子：
1.6
作者：
Ehrmann;Hillenbrand;Graham;Larter
通讯作者：
Larter
影响因子：
12.1
作者：
Livingstone, Stephen J.;Cofaigh, Colm O.;Jamieson, Stewart S. R.
通讯作者：
Jamieson, Stewart S. R.