Graptolite faunas from the Ballantrae ophiolite complex and their structural implications
Graptolite faunas from the Ballantrae ophiolite complex and their structural implications
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Ballantrae 蛇绿岩杂岩中的笔石动物群及其结构意义
DOI：
10.1144/sjg19030297
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发表时间：
1983
影响因子：
0.7
通讯作者：
A. Rushton
中科院分区：
文献类型：
--
作者：
P. Stone;A. Rushton
来自Ballantrae复杂的Bennane Head地区的笔石表明年龄范围从最低的Arenig（Lancefieldian，与Tetragraptus近似）到中间的Arenig（Chewtonian）。笔石动物群的分布强烈地表明了它们所包含的熔岩和层间碎屑沉积物序列的构造重复。这对先前关于该复合体内部存在厚得惊人的火山序列的假设提出了一些质疑，这一特征被广泛引用，以支持其起源的各种提议。相反，不同年龄和起源的火山序列在结构上似乎是并列的。较老的中下阿雷尼希火山岩的起源是混乱的，但一个较年轻的中上阿雷尼希序列似乎是岛弧的产物。在两次火山爆发之间有一个主要的逆冲作用阶段。
Synopsis Graptolites from the Bennane Head area of the Ballantrae complex indicate ages ranging from lowest Arenig (Lancefieldian, with Tetragraptus approximates) to middle Arenig (Chewtonian). The distribution of the graptolite faunas strongly suggests a tectonic repetition of the sequence of lavas and interbedded clastic sediments in which they are contained. This throws some doubt on previous assumptions of an anomalously thick volcanic succession within the complex, a feature which has been widely quoted in support of the various proposals for its origin. Instead it seems likely that volcanic sequences of different ages and origins have been structurally juxtaposed. The origins of the older, lower-middle Arenig volcanics are confused but a younger, middle-upper Arenig sequence seems likely to be the product of an island arc. A phase of major thrusting intervened between the two volcanic episodes.