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在湖北省京山县雁门口地区二叠世栖霞组上部的含泥灰岩中发现棘皮动物化石,其腔被不同形态微晶的草莓状黄铁矿充填,有正四面体、正六面体、五角十二面体和近球体。溶解氧与草莓状黄铁矿的形成过程有关,其浓度决定微晶的S/Fe。统计显示,黄铁矿的S/Fe平均值随微晶的边数增加而增加,所以,棘皮动物腔内草莓状黄铁矿形成由早及晚的次序为:近球体微晶,五角十二面体微晶,正六面体微晶,正四面体微晶的草莓状黄铁矿。同一环境中,黄铁矿微晶的S/Fe可用来指示形成次序。
The echinoderm fossils are found in the upper marl of the Permian Qixia Formation in the Yanmenkou area, Jingshan County, Hubei Province. The cavities of the echinoderm are filled with strawberry-shaped pyrite with different morphologies of crystallites, with regular tetrahedrons, regular hexahedra, Dihedrals and near-sphere. Dissolved oxygen is related to the formation of strawberry pyrite, and its concentration determines the crystallite S / Fe. Statistics show that the average S / Fe of pyrite increases with the increase of the number of crystallite edges. Therefore, the order of early and late strawberry pyrite formation in the echinoderm is: near-sphere crystallite, pentagonal twelve Facet crystallite, regular hexahedron crystallite, and regular tetrahedron crystallite strawberry-like pyrite. In the same environment, the S / Fe of pyrite crystallites can be used to indicate the order of formation.