瓮安震旦系磷块岩中的生物成矿作用

摘要

Biological accumulation of phosphorus was an important factor for formation of phosphorite.The large marine phosphorite deposits are closely related to the biomineralization.In the central Guizhou province occur thick Sinain phosphorite layers which may deposited by stimulation of recovery and flourishing of the Sinian biota.Organic material is extracted from the Sinain P-rich strata in Weng'an area and analyzed it to molecular scale with biomark technique.Result shows that the hydrocarbons fractions contained n-alkanes,terpanes,steranes and so on implying that the sources of the organic matters in phosphorite came from algaes and bacteria.δ(13C) value variation curve of n-alkanes indicates that species of medium-low organism in the post Nantuo glacial epoch ocean is unitary.%生物的聚磷作用是磷块岩形成不可忽视的因素,海相磷块岩的大规模形成与生物成矿作用之间的关系十分密切.黔中地区震旦系有较厚的含磷岩层,震旦纪生物群的复苏和繁盛可能对同期磷块岩的沉积有促进作用.文章以震旦系瓮安富磷地层中抽提的有机组分为主要研究载体,采用生物标志物等技术从分子水平对其进行测试.结果表明:正构烷烃等多种分子化石的存在,暗示其生物母质源于菌藻类;正构烷烃δ(13 C)值变化曲线反映了南沱冰期后海洋中低等水生生物的种类相对单一.