Diagenesis of Inoceramus and late Cretaceous paleoenvironmental geochemistry: a case study from James Ross Island, Antarctica
Diagenesis of Inoceramus and late Cretaceous paleoenvironmental geochemistry: a case study from James Ross Island, Antarctica
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Inoceramus 的成岩作用和晚白垩世古环境地球化学：以南极洲詹姆斯罗斯岛为例
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发表时间：
1990
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影响因子：
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通讯作者：
J. Marshall
中科院分区：
文献类型：
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作者：
D. Pirrie;J. Marshall
对南极洲詹姆斯罗斯岛桑托尼亚-坎帕尼亚纪的双壳类和双裂贝壳类进行了同位素和元素地球化学分析。根据岩相学、阴极发光研究和微量元素数据，二辉橄榄岩具有最小的成岩改造作用。这些数据是按照分层水柱模型解释的。表层动物群的双壳类被认为生活在底层水域，那里的同位素组成被下面压实的火山碎屑沉积物排出的孔隙水改变了。相比之下，nekonic belemmites生活在更“正常”的海洋条件下。根据贝莱姆石的同位素组成计算的古温度显示，“正常”海水的平均温度为13.6摄氏度。然而，根据双壳贝类数据得出的古温度意味着相当高的数值。
Inoceramid bivalves and dimitobelid belemnites from the Santonian-Campanian of James Ross Island, Antarctica, were analyzed for their isotopic and elemental geochemistry. On the basis of petrographic and cathodoluminescence studies and minor element data, the dimitobelid belemnites show minimal diagenetic modification. These data are interpreted in terms of a stratified water column model. Epifaunal inoceramid bivalves are thought to have lived in bottom waters where the isotopic composition was modified by pore waters expelled from the underlying compacting volcaniclastic sediments. In contrast, the nektonic belemnites were living within more «normal» marine conditions. Paleotemperatures calculated from the isotopic composition of the belemnites give an average of 13.6°C for the «normal» marine waters. However, paleotemperatures based on the inoceramid bivalve data imply considerably higher values