middle-upper Silurian的意思|示意

Unless the upper part of Ningqiang Formation maybe belongs to Middle Silurian, the others belong to lower Silurian.

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。

The lead-zinc deposits occur in the Lower Silurian Meiziya Formation, Middle Silurian Shuanghezhen Formation, Middle Devonian Dafenggou Formation and Upper Devonian Nanyangshan Formation.

铅锌矿赋存于下志留统梅子垭组、中志留统双河镇组及中泥盆统大枫沟组、上泥盆统南羊山组；

Vertically, 3sets of source rocks including the Lower Cambrian, the Middle-o-Upper Ordovician-Lower Silurian 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。