...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Global and planetary change >Dynamics of the late Plio-Pleistocene West Antarctic Ice Sheet documented in subglacial diamictites, AND-1B drill core
【24h】

Dynamics of the late Plio-Pleistocene West Antarctic Ice Sheet documented in subglacial diamictites, AND-1B drill core

机译：冰川下的铁白云岩，AND-1B钻芯中记载的晚期上新世西极南极冰盖的动力学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Geologic studies of sediment deposited by glaciers can provide crucial insights into the subglacial environment. We studied muddy diamictites in the ANtarctic geological DRILLing (ANDRILL) AND-1B drill core, acquired from beneath the Ross Ice Shelf in McMurdo Sound, with the aim of identifying paleo-ice stream activity in the Plio-Pleistocene. Glacial advances were identified from glacial surfaces of erosion (GSEs) and subglacial diamictites within three complete sequences were investigated using lithofacies associations, micromorphology, and quartz sand grain microtextures. Whereas conditions in the Late Pliocene resemble the modern Greenland Ice Sheet where fast flowing glaciers lubricated by surface meltwater terminate directly in the sea (interval 201-212 mbsl) conditions in the Late Pleistocene are similar to modem West Antarctic Ice Sheet (WAIS) ice streams (38-49 mbsl). We identify the latter from ductile deformation and high pore-water pressure, which resulted in pervasive rotation and formation of till pellets and low relief, rounded sand grains dominated by abrasion. In the transitional period during the Mid-Pleistocene (55-68 mbsf), a slow moving inland ice sheet deposited tills with brittle deformation, producing lineations and bi-masepic and unistrial plasma fabric, along with high relief, conchoidally fractured quartz grains. Changes in the provenance of gravel to cobble-size clasts support a distant source area of Byrd Glacier for fast-flowing paleo-ice streams and a proximal area between Darwin and Skelton Glaciers for the slow-moving inland ice sheet. This difference in till provenance documents a shift in direction of glacial flow at the core site, which indirectly reflects changes in the size and thickness of the WAIS. Hence, we found that fast ice streaming motion is a consequence of a thicker WAIS pushing flow lines to the west and introducing clasts from the Byrd Glacier source area to the drill site. The detailed analysis of diamictites in AND-1B demonstrates that Pliocene glacial intervals were warmer than in the Pleistocene when polar ice sheets grew from local inland ice to regional ice streams. (C) 2014 Elsevier B.V. All rights reserved.
机译：冰川沉积物的地质研究可以提供对冰下环境的重要见解。我们研究了南极地质钻探（ANDRILL）AND-1B钻芯中的泥状铁矾土，该钻芯是从麦克默多湾的罗斯冰架下方采集的，目的是识别上新世的古冰流活动。从侵蚀的冰川表面（GSEs）确定了冰川的进展，并使用岩相学关联，微观形态学和石英砂纹微纹理研究了三个完整序列中的亚冰晶石。晚更新世的情况类似于现代的格陵兰冰原，由表层融化水润滑的快速流动冰川直接终止于海中（间隔201-212 mbsl），晚更新世的状况与现代南极冰原（WAIS）的冰流相似。 （38-49 mbsl）。我们从延性变形和高孔隙水压力中识别出后者，这导致了普遍的旋转和耕作球团的形成以及低起伏，磨粒为主的圆形沙粒。在中更新世（55-68 mbsf）的过渡时期，缓慢移动的内陆冰原沉积下来，直至形成脆性变形，产生线型，双峰形和单层等离子织物，以及高浮雕，贝壳状破裂的石英晶粒。砾石到碎石大小碎屑物源的变化为快速流动的古冰流提供了一个伯德冰川的遥远源区域，而对于内陆冰原缓慢的移动则支持了达尔文和斯凯尔顿冰川之间的近端区域。耕种出处的这种差异证明了核心位置冰川流动的方向发生了变化，这间接反映了WAIS大小和厚度的变化。因此，我们发现快速的冰流运动是较厚的WAIS将流线推向西部并将碎屑从伯德冰川源区引入钻井现场的结果。对AND-1B中的铁矾的详细分析表明，当极地冰盖从本地内陆冰流向区域冰流生长时，上新世的冰川间隔比上新世的冰川间隔要温暖。 （C）2014 Elsevier B.V.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号