Post-LGM deglaciation in Pine Island Bay, West Antarctica
Post-LGM deglaciation in Pine Island Bay, West Antarctica
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DOI：
10.1016/j.quascirev.2012.01.017
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发表时间：
2012-03-30
影响因子：
4
通讯作者：
Nitsche, Frank O.
中科院分区：
文献类型：
--
作者：
Kirshner, Alexandra E.;Anderson, John B.;Nitsche, Frank O.
到目前为止，了解冰盖退缩后，松岛湾（PIB）的末次盛冰期（LGM）的基础上，七个放射性碳日期和只有零碎的海底地貌证据。在2009-2010年夏季，有限的海冰覆盖允许收集27个沉积物芯从外部PIB槽区。将这些岩心与以前航行的数据相结合，使用了超过133个岩心进行详细的沉积相分析。这些结果，增加了23个新的放射性碳测年，被用来重建后末次冰期冰消历史的PIB。我们的研究结果记录了一个明确的撤退地层PIB组成，从顶部到底部，陆源桑迪粉土（远端glacimarine），含砾桑迪泥（冰近端glacimarine），直到。最初的撤退从外大陆架开始后不久，末次盛冰期和16.4千卡BP前，作为一个可能的响应海平面上升。PIB外部的底形记录了以后退接地带楔形物形式出现的幕式后退，并与近端冰川沉积物相关。在中央PIB和跨度类似于12.3-10.6千卡年BR观察到一个亚冰架相。这是可能的，广泛的热水冲击到大陆架上造成了突然和广泛的变化，从亚冰架沉积到远端冰川沉积为主的广泛分散的陆源粉砂之间的7.8和7.0千卡年BP。撤退的最后阶段结束前类似于1.3千卡BP，接地线迁移到当前冰缘附近的位置。(C)2012爱思唯尔有限公司保留所有权利。
To date, understanding of ice sheet retreat within Pine Island Bay (PIB) following the Last Glacial Maximum (LGM) was based on seven radiocarbon dates and only fragmentary seafloor geomorphic evidence. During the austral summer 2009-2010, restricted sea ice cover allowed for the collection of 27 sediment cores from the outer PIB trough region. Combining these cores with data from prior cruises, over 133 cores have been used to conduct a detailed sedimentological facies analysis. These results, augmented by 23 new radiocarbon dates, are used to reconstruct the post-LGM deglacial history of PIB.Our results record a clear retreat stratigraphy in PIB composed of, from top to base; terrigenous sandy silt (distal glacimarine), pebbly sandy mud (ice-proximal glacimarine), and till. Initial retreat from the outer-continental shelf began shortly after the LGM and before 16.4 k cal yr BP, as a likely response to rising sea level. Bedforms in outer PIB document episodic retreat in the form of back-stepping grounding zone wedges and are associated with proximal glacimarine sediments. A sub-ice shelf facies is observed in central PIB and spans similar to 12.3-10.6 k cal yr BR It is possible that widespread impingement of warm water onto the continental shelf caused an abrupt and widespread change from sub-ice shelf sedimentation to distal glacimarine sedimentation dominated by widespread dispersal of terrigenous silt between 7.8 and 7.0 k cal yr BP. The final phase of retreat ended before similar to 1.3 k cal yr BP, when the grounding line migrated to a location near the current ice margin. (C) 2012 Elsevier Ltd. All rights reserved.