摘要
我国的早前寒武纪沉积变质型晶质石墨矿床主要赋存在孔兹岩系以及与之类似的变质沉积岩系中。对其地质特征及原岩的形成环境进行了探讨。该类矿床的成矿时代多集中在晚太古代末至早元古代初期,并且具有全球性。反映在该地史发展阶段,地球已进入一个低等海洋生物的繁盛时期。
The Early Precambrian metasedimentary crystalline graphite deposits in China mainly occur in khondalite series and similar metasedimentary series.Protoliths of these graphite-breaing formations are a series of shallow-sea carbonaceous sedimentary sequences of clastics,marl and carbonate sediments and deposited at the margin of some stable cra- tons which were formed locally at the early stage of the evolution of the earth's crust. Carbon isotopic evidence surpports the organic earbon sources of graphite ores and the an- cient depositional environment of them is also discussed.This type of graphite deposits were formend in the Late Archaean to Early Proterozoic.Many graphi e deposits with the same origin and age are found all over the world,which implies that the earth entered a flourishing epoch of low-grade marine creatures at the Late Archaean to Early Proterozoic.
