A Silurian Deep Sea Fan Deposit in Western Ireland and Its Bearing on the Nature of Turbidity Currents
A Silurian Deep Sea Fan Deposit in Western Ireland and Its Bearing on the Nature of Turbidity Currents
复制标题
爱尔兰西部志留纪深海扇沉积物及其对浊流性质的影响
DOI：
10.1086/627549
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发表时间：
1970
期刊：
影响因子：
--
通讯作者：
D. Piper
中科院分区：
文献类型：
--
作者：
D. Piper
高伦段由泥岩组成，带有两个透镜，宽几公里，由粗砂岩和砾岩组成。地层证据表明，该段沉积于海平面以下100m以上的深度，解释为浅海陆架与较深盆地之间的斜坡区和海底扇沉积，积累了浊积岩。较粗的岩性通常是河道充填，与现代深海扇谷的沉积非常相似。许多砾岩都是卵石级的，包装和分选得很好，在层理中有首选的卵石方向。有些是叠瓦状的，表明南边有古水流。个别层的分选、叠置、沟槽和厚度表明，它们是由强大洋流的牵引推移质沉积的，在深海环境中，这可能是浑浊洋流。戈伦组的粗砂岩和细砾岩表现出颗粒流机制沉积的特征。
The Gowlaun Member comprises mudstones with two lenses, several kilometers wide, of coarse sandstones and conglomerates. Stratigraphic evidence shows the member was deposited at depths of more than 100 m below sea level, and it is interpreted as the deposits of a slope area and submarine fans between a shallow continental shelf and deeper basins accumulating turbidites. The coarser lithologies are often channel filling, and show close resemblances to the deposits of modern deep-sea fan valleys. Many of the conglomerates are of cobble grade, are well packed and sorted, and have a preferred orientation of pebbles within bedding planes. Some are imbricated, indicating paleocurrents to the south. The sorting, imbrication, channeling, and thinness of individual beds suggest that they were deposited from traction bed load of powerful currents, which in a deep-sea environment were presumably turbidity currents. The coarse sandstones and fine conglomerates of the Gowlaun Member show features suggestive of deposition by a grain flow-mechanism.