Palaeoenvironmental Control on Distribution of Crinoids in the Bathonian (Middle Jurassic) of England and France
Palaeoenvironmental Control on Distribution of Crinoids in the Bathonian (Middle Jurassic) of England and France
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DOI：
10.4202/app.2009.0109
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发表时间：
2009-03
期刊：
影响因子：
--
通讯作者：
A. Hunter;C. Underwood
中科院分区：
文献类型：
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作者：
A. Hunter;C. Underwood
大量采样的一些不同的海洋和边缘海洋岩相在英国的Escherichian使我们能够评估海百合的古环境分布的第一次。虽然仍然是大部分碎片，许多物种已被确定与其他地方的铰接标本比较，而大和公正的样本大小允许不同类群的相对比例进行评估。结果表明，海百合的分布与特定的沉积相有较好的对应关系。在深水低能相，Chariocrinus和Balanocrinus的小骨占优势，前者比后者更深入浅水相。Isocrinus占主导地位的浅水碳酸盐相，伴随着罕见的comatulids，也存在于泻湖的海洋部分。在极高能的鲕滩岩相中富含五碧岩遗迹。millericrinids在一个，部分异地岩相的存在表明，存在一个否则未知的硬基板，他们已被运输。这些结果进行了比较海百合组合从其他中生代的地方，很明显，同样的形态适应海百合从类似的岩相在整个侏罗纪和早白垩世。
Bulk sampling of a number of different marine and marginal marine lithofacies in the British Bathonian has allowed us to assess the palaeoenvironmental distribution of crinoids for the first time. Although remains are largely fragmentary, many species have been identified by comparison with articulated specimens from elsewhere, whilst the large and unbiased sample sizes allowed assessment of relative proportions of different taxa. Results indicate that distribution of crinoids well corresponds to particular facies. Ossicles of Chariocrinus and Balanocrinus dominate in deeper-water and lower-energy facies, with the former extending further into shallower-water facies than the latter. Isocrinus dominates in shallower water carbonate facies, accompanied by rarer comatulids, and was also present in the more marine parts of lagoons. Pentacrinites remains are abundant in very high-energy oolite shoal lithofacies. The presence of millericrinids within one, partly allochthonous lithofacies suggests the presence of an otherwise unknown hard substrate from which they have been transported. These results are compared to crinoid assemblages from other Mesozoic localities, and it is evident that the same morphological adaptations are present within crinoids from similar lithofacies throughout the Jurassic and Early Cretaceous.