Unless the upper part of Ningqiang Formation maybe belongs to Middle Silurian, the others belong to lowerSilurian.
本区绝大部分地层为下志留统，只有宁强组上部可能为中志留统。
2
Vertically, 3sets of source rocks including the Lower Cambrian, the Middle-o-Upper Ordovician-LowerSilurian and the Permian were developed in Chinese Paleozoic Marine basins.
研究认为中国古生代海相盆地在纵向上主要发育下寒武统、中上奥陶统—下志留统和二叠系3套烃源岩。
3
The geological and geochemical study results indicate that the metallogenetic materials came from the hydromica mudstones and shales of the Hanjiadian Group of LowerSilurian System.