Sedimentation studies in the silurian rocks of north-west Galway, Eire
Sedimentation studies in the silurian rocks of north-west Galway, Eire
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爱尔兰戈尔韦西北部志留纪岩石的沉积研究
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发表时间：
1969
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通讯作者：
M. Laird
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作者：
M. Laird
高威西北部的志留纪岩石是一个至少2700米厚的碎屑序列，不整合地位于南部的康内马拉片岩（Dalradian）和东北部的奥陶纪岩石上。志留系的完整厚度是看不到的，因为在西部，它是由奥多维克兰地层的逆冲断层，在东部，年轻的地层已被侵蚀移走。最早的志留纪岩石（Llandoverian晚期）可能是在陆地和三角洲条件下沉积的，随后是一次海侵，在海侵期间，富含碳酸盐的浅海沉积物堆积起来。上覆的Wenlockian层序由底部的巨砾层和厚度很大（约1500 m）的分级砂岩组成，向上进入浅海含矿粉砂岩和砂岩。最年轻的层是稀疏的红色粉砂岩和泥岩。本研究仅限于基拉里港地区的温洛克岩，即，在最低的陆地和浅海沉积之上。地层进行了修订，并提出了新的细分。保留了上奥瓦洛夫群（McKerrow和坎贝尔，1960年）的名称，但重新定义了该群的上限，以排除上部含盐浅海沉积物，并将其分为两个新的地层，即Lettergesh和Glencraff，主要由分级砂岩组成。一个新的组名，基拉里港组，提出了文洛克阶的最高浅海部分。它包括新定义的含矿湖淤泥层和萨尔岩层，其特征是红色的床。[see pdf文件的完整摘要]。
The Silurian rocks of north-west Galway are a clastic sequence at least 2700 m thick resting unconformably on Connemara Schist (Dalradian) in the south and on Ordovlcian rocks in the north-east. The full thickness of Silurian is not seen, as in the west it is aver thrust by Ordoviclan strata, and in the east the younger beds have been removed by erosion. The earliest Silurian rocks (Upper Llandoverian) were probably deposited under terrestrial and deltaic conditions, and were followed by a transgression during which fossiliferous shallow marine sediments accumulated. The overlying Wenlockian succession consists of basal boulder beds and a great thickness (approximately 1500 m) of graded sandstones, passing up into shallow marine fossiliferous siltstone and sandstone. The youngest beds are sparsely-fossiliferous red siltstones and mudstones. The present study is limited to the Wenlockian rocks of the Killary Harbour area, i.e., those above the lowermost terrestrial and shallow marine deposits. The stratigraphy is revised, and new subdivisions proposed. The name Upper Owenduff Group (McKerrow and Campbell, 1960) is retained, but the upper limit of the group is redefined to exclude the upper fossiliferous shallow marine sediments and is divided into two new formations, the Lettergesh and the Glencraff, consisting dominantly of graded sandstones. A new group name, the Killary Harbour Group, is proposed for the uppermost shallow marine portions of the Wenlockian. It comprises the newly-defined fossiliferous Lough Muck Formation, and the Sal rock Formation, with its characteristic red beds ... [see pdf file for full abstract].