The deforming bed characteristics of a stratified till assemblage in north East Anglia, UK: investigating controls on sediment rheology and strain signatures
The deforming bed characteristics of a stratified till assemblage in north East Anglia, UK: investigating controls on sediment rheology and strain signatures
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英国东北安格利亚分层耕作组合的变形床特征：调查沉积物流变学和应变特征的控制
DOI：
10.1016/j.quascirev.2004.03.004
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发表时间：
2004
影响因子：
4
通讯作者：
J. Hart
中科院分区：
文献类型：
--
作者：
D. Roberts;J. Hart
北诺福克的冰川海岸暴露是冰下冰川构造变形床沉积的典型场所。对西伦顿北海漂流带内低层结的研究揭示了两种不同的纹层类型。1型纹层是原生伸展冰川构造作用的产物，韧性、粒间普遍剪切作用占主导地位。2型纹层也表现出结构，可以归因于韧性，粒间普遍剪切和脆性剪切，但2型纹层的横向连续性和存在的dropstone状结构支持一个主要的水下起源与次级冰下变形。当再加上微形态分析，这些研究结果表明，韧性，粘性蠕变机制控制沉积结构，特别是“剪切分层”，有可能影响流变特性的沉积物桩和水力路由的基础水，最终影响临界有效压力波动和阈值控制冰下排水系统。
The glacial coastal exposures of north Norfolk are a type site for subglacial glaciotectonic deforming bed sediments. This investigation of the lower stratified diamict within the North Sea Drift at West Runton reveals two distinct lamina types. Type 1 laminae are the product of primary extensional glaciotectonism, with ductile, intergranular pervasive shear predominating over brittle shear. Type 2 laminae also exhibit structures that can be attributed to ductile, intergranular pervasive shear and brittle shear, but the lateral continuity of Type 2 laminae and the presence of dropstone—like structures supports a primary subaqueous origin with secondary subglacial deformation. When coupled with micromorphological analysis, these findings show that ductile, viscous creep mechanisms control sedimentary architecture, and that ‘shear stratification’ in particular, has the potential to affect the rheological properties of the sediment pile and the hydraulic routing of basal water, ultimately influencing critical effective pressure fluctuations and the thresholds controlling the subglacial drainage system.