Experimental Studies of Gas-Escape and Water-Escape Structures: Mechanisms and Morphologies
Experimental Studies of Gas-Escape and Water-Escape Structures: Mechanisms and Morphologies
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DOI：
10.2110/jsr.2009.087
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发表时间：
2009-11
影响因子：
2
通讯作者：
S. Frey;M. Gingras;S. Dashtgard
中科院分区：
文献类型：
--
作者：
S. Frey;M. Gingras;S. Dashtgard
在实验室中生成了水逸和气逸结构，以评估在这些事件中产生的变形结构的变化。颗粒流化被认为是水逸出过程中颗粒重新分布的一种方法。由此产生的颗粒流化结构包括破碎和向下偏转的初级层，以及点源上方出现的块状砂柱。气体实验中，低流速（6.167 × 10−6 m3/s）允许气体通过裂缝分散，只产生轻微的变形。聚集流化（即流体以气泡形式通过沉积物）是气体逸出过程中颗粒位移的机制。随着流量的增加（7.67 × 10−5 m3/s），颗粒在气泡通过后向上流动。聚集流化导致破碎、向上翘曲的层合和卷曲的层理。实验表明，水逸出与气逸出在形态上存在显著差异。泄水构造以向下弯曲的层状物为界，与岩石记录中遇到的泄水构造一致。气体逸出构造表现出向上翘曲的层状结构，可能代表了卷曲层理的形成机制。
Abstract Water-escape and gas-escape structures were generated in the laboratory to assess variations in deformational structures generated during these events. Particulate fluidization was observed to be the method by which grains were redistributed during water escape. Resulting structures of particulate fluidization comprised disrupted and downward-deflected primary laminations, and a massive-appearing column of sand above the point source. Gas experiments, with a low flow rate (6.167 × 10−6 m3/s) allowed gas to disperse through fractures, and only subtle deformation was achieved. Aggregative fluidization (i.e., fluid movement through sediment as bubbles) was the mechanism for grain displacement during gas escape. With increased flow rate (7.67 × 10−5 m3/s) aggregative fluidization occurred and particles were carried upward in the wake of the passing gas bubble. Aggregative fluidization resulted in broken, upwards-warping laminations and convoluted bedding. Experiments illustrate a significant morphological difference between water escape and gas escape. Water-escape structures were bounded by downwards-warping laminations, consistent with water-escape structures encountered in the rock record. Gas-escape structures displayed upwards-warping laminations, and could represent a formation mechanism for convolute bedding.