The ice/bed interface mosaic: deforming spots intervening with stable areas under the fringe of the Scandinavian Ice Sheet at Sampława, Poland
The ice/bed interface mosaic: deforming spots intervening with stable areas under the fringe of the Scandinavian Ice Sheet at Sampława, Poland
复制标题
冰/床界面马赛克：波兰桑普瓦瓦斯堪的纳维亚冰盖边缘下稳定区域的变形点
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
W. Wysota
中科院分区：
文献类型：
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作者：
Karol Tylmann;J. Piotrowski;W. Wysota
暴露于波兰的斯堪的纳维亚晚期韦克塞尔期冰盖南缘附近的冰川沉积物序列揭示了一个镶嵌体，由缺乏任何可见变形证据的区域分隔的孤立的重度变形沉积物斑块组成。在所研究的露头中，冰下变形斑宽约2-10 m，厚约20-60 cm，由冰水沉积物夹冰碛细脉组成。它们位于冰水沉积物上，并被基底冰碛物覆盖。基于结构和纹理特征，变形点被解释为以前的R通道充满了融水沉积物。在变形点正下方和通道之间的中间区域，冰水沉积物没有变形，这表明冰床被冻结，通道填充物的变形是由高孔隙水压力促进的，因为水排入床中受到永久冻土的阻碍。河道充填沉积物和紧接在其上方的冰碛物发生了应变小于9的共形变形。这项研究记录了冰盖下变形和稳定区域的可能共存，这是由影响沉积物流变学的空间变化的热和水文条件产生的。
The glacial sediment succession exposed close to the southern margin of the Late Weichselian Scandinavian Ice Sheet in Poland reveals a mosaic consisting of isolated patches of heavily deformed deposits separated by areas lacking any visible evidence of deformation. In the studied outcrop, the subglacial deforming spots composed of outwash deposits intercalated with till stringers are about 2–10 m wide and 20–60 cm thick. They rest on outwash sediments and are covered by a basal till. Based on structural and textural characteristics, the deforming spots are interpreted as previous R‐channels filled with meltwater deposits. Lack of deformation in outwash sediment immediately beneath the deforming spots and in the intervening areas between the channels suggests that the ice‐bed was frozen and the deformation of the channel infill was facilitated by high pore‐water pressure arising because water drainage into the bed was impeded by permafrost. Channel infill deposits and the till immediately above were coevally deformed to a strain of less than 9. This study documents the possible co‐existence of deforming and stable areas under an ice sheet, generated by spatially varying thermal and hydrological conditions affecting sediment rheology.
影响因子：
3.4
作者：
Clark C
通讯作者：
Clark C