Sedimentary structures of tidal flats: A journey from coast to inner estuarine region of eastern India
Sedimentary structures of tidal flats: A journey from coast to inner estuarine region of eastern India
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DOI：
10.1007/bf02702954
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发表时间：
2005-06-01
影响因子：
1.9
通讯作者：
Chakrabarti, A
中科院分区：
文献类型：
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作者：
Chakrabarti, A
在不同的季节条件下，广泛研究了印度东海岸一些沿海热带潮滩和位于距海岸30~50公里的内河口潮点沙洲的沉积结构。结果表明，板状层理、人字形交错层理、透镜状层理、泥沙对偶等物性特征在两种环境中都具有共性。事实上，与沿海潮滩环境相比，在季风期间，点坝相中更常见的是片状层理和透镜状层理。干扰涟漪虽然在两个环境中都很常见，但在不同的环境领域显示出不同的架构模式。高水区附近河口点坝的典型特征是纹状次生组的干扰波纹盖过早期的波纹状，类似皱纹。由于迄今为止被认为是近海潮滩关键构造的构造在这两个环境中都是共同的，因此在破译古环境时应谨慎行事，特别是对于元古界岩石，因为人们只能依赖物理沉积构造。
Sedimentary structures of some coastal tropical tidal flats of the east coast of India, and inner estuarine tidal point bars located at 30 to 50 kilometers inland from the coast, have been extensively studied under varying seasonal conditions. The results reveal that physical features such as flaser bedding, herringbone cross-bedding, lenticular bedding, and mud/silt couplets are common to both the environments. In fact, flaser bedding and lenticular bedding are more common in the point bar facies during the monsoon months than in the coastal tidal flat environments. Interference ripples, though common in both the environments, show different architectural patterns for different environmental domains. Interference ripples with thread-like secondary set overriding the earlier ripple-form, resembling wrinkle marks, are the typical features in estuarine point bars near the high water region. Because structures which are so far considered as key structures for near-coastal tidal flats are common to both the environments, caution should be exercised for deciphering palaeo-environments, particularly for Proterozoic rocks, where one has to depend only on physical sedimentary structures.