Organic clots and their differential accumulation of Ni and Mo within early Cambrian black-shale-hosted polymetallic Ni-Mo deposits, Zunyi, South China

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• 作者：Jian Cao^a ; ^{jcao@nju.edu.cn} ; Kai Hu^a ; Jie Zhou^a ; ^b ; Chunhua Shi^a ; Lizeng Bian^a ; Suping Yao^a
• 关键词：Ni&ndash ; Mo polymetallic deposits ; Rhodophyta ; Cystocarp ; Black shale ; Early Cambrian Terraneuvian Series ; South China
• 刊名：Journal of Asian Earth Sciences
• 出版年：2013
• 出版时间：30 January, 2013
• 年：2013
• 卷：62
• 期：Complete
• 页码：531-536
• 全文大小：1716 K

文摘

The celebrated early Cambrian Ni-Mo deposits that occur near Zunyi City of Guizhou Province, South China, are hosted in shales. The ore formation has been widely accepted to be related to biotic impact, but direct evidence is still lacking. In the present study of the Huangjiawan ore deposit, organic clots are found to occur widely in the Ni-Mo ore beds, but not in the barren layers. The clots are generally elliptic, with sizes ranging from 200 to 600 ¦Ìm. The clot morphology is similar to that of modern rhodophyta as reported in the literature. We tentatively interpret the clots as rhodophyte cystocarps. Electron microprobe analysis revealed that the clots have a differential accumulation of Ni and Mo, with Ni in the inner part and Mo in the outer part (of the cystocarp). Our study seems to have provided direct evidence for the biotic impact on the ore mineralization.