湖北震旦系磷块岩中的藻类化石

湖北荆襄地区震旦系陡山沱组磷块岩特别发育,含丰富的藻类化石。陡山沱组有四层磷块岩,第一层含叠层石和核形石,第三、四层含核形石。叠层石柱体被磷酸岩紧密包裹者,品位较高;基本层理由磷灰石与白云石交替组成亮层和暗层者,品位较低;柱体中仅含团粒状磷灰石者,品位更低。

ALGAL FOSSILS OF SIMIAN PHOSPHORITE IN HUBEI

Phosphorite with abundant stromatolite in the Doushantuo Formation of Sinian System is well-developed and widespread in the Jingmen-Xiangyang region of Hubei. There are four phosphorite-beds, the first one consists of stromatolite, Baicalia minuta Komar, B. ampla Semikhatov, Conophyton yichengensis Cao (f. nov.), C. miloradovici Raaben, C. f., Paraconophyton hubeiensis Cao (f. nov.), Compactocol-lenia tuvensis Kor.; the second oncolite Osagia jianshanensis Cao (f.nov); the third oncolite Osagia minuta Z. Zhur. and the fourth oncolite, Osagia nersinica Yakschin and O. f.. P2O5 in the stromatolitic phosphorite accounts for 37.5% while the P2O5 in the oncolitic phosphorite 16-19% or less. Usually phosphorite appears in the offshore near platform, and is a kind of biochemigenic deposits.