吉南珍珠门组的解体与古-中元古界层序的重建

The disintergration of the Zhenzhumen Formation and the reconstruction of the paleo-middle Proterozoic Group

辽东吉南是我国古-中元古界发育最好的地区之一,但两省古-中元古界地层划分方案并不一致,使两省古-中元古界地层无法对比。通过岩石组合、构造变形、地球化学、年代及生物地质特征的对比发现Ⅰ、Ⅱ区镁质大理岩是在不同地质时期、不同大地构造环境下形成的。Ⅰ区时代为中元古代,Ⅱ区时代为古元古代。对吉南古-中元古界层序进行了重新划分。中元古界划分为大红峪组和高于庄组。古元古界划分为集安群、临江群、大栗子群。

The paleo-middle Proterozoic strata are both best exposed in the eastern Liaoning and southern Jilin Provinces. However, their correlation is very difficult for different classification schemes used by the two provinces. By comparison of the magnesium marble of the Zhenzhumen Formation in rock association, tectonic sequence, REE geochimestry, chronostratigraphy and paleo-biology in both Ⅰand Ⅱareas, it is concluded that these marbles were formed in different geologic periods and different tectonic settings. The marbles in Ⅰarea were formed in middle Proterozoic while the marbles in Ⅱarea were formed in palaeo-Proterozoic. A new classification scheme is proposed for the palaeo-middle Proterozoic strata in southern Jilin Province by the present authors, in which the middle Proterozoic strata contain two formations:Dahongyu and Gaoyuzhuang Formations while the palaeo Proterozoic strata include Ji'an, Linjang, and Dalizi Groups.