Trace elemental geochemistry of black shale from Chengkou District, Chongqing, southwest China and its genetic significances.

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• 责任者：Li ; H. ; Zhu ; Z. ; Zhu ; C. ; Luo ; T.
• 年：2011
• 作者单位：Chongqing Institute of Geology and Mineral Resources, Laboratory of Exogenic Minerallization and Mine Environment, Chongqing, China.
• 刊：Mineralogical Magazine.
• 期：75,3

摘要

The black rock series in Lower Cambrian are well developed in Chengkou district, Chongqing, representing a potentially large multi-metal deposit source in China. Previous study in Chengkou district showed that multi-metals including Ag, V, Se are enriched in black shale. In order to understand the genetic significances of black shale and multi-metal enrichment, ICP-MS techniques was used to analyze trace elemental contents in Lower Cambrian black rock series including cherts, black siltstones and multi-elements concentrated layers. The results indicated that REE is very low relative to other regions such as northern Guizhou, northwestern Hunan, and LREE is relative abundant. delta Ce shows almost negative anomaly, and delta Eu shows unconspicuous anomaly. The indicators of delta Ce, delta U, V/Cr, Ni/Cr and V/(V+Ni) demonstrated that black rock series formed in the anoxic environment. REE geochemical characteristics and their diagrams, high enrichments of Cr, Sb, As, Bi and U/Th ratios indicated that black rock series mainly formed by hydrothermal deposition. Meanwhile, the petrogenesis of black rock series was associated with volcanism, and volcanism possibly provided the composition and dynamics to the hydrothermal activity.