山西宁武煤田的大同组

The Datong Formation of Ningwu Coalfield, Shanxi

宁武煤田的大同组主要由黄绿色、灰绿色砂岩、砂质泥岩、粉砂岩及泥岩组成，夹有薄层灰岩及煤层，为一套湖泊到湖泊三角洲相含煤沉积。底界置于铜川组紫红色泥岩之顶，顶界为云岗组灰绿色砂岩之底，厚２８３～４６１ｍ。本组含丰富的植物化石，可归于Ｃｏｎｉｏｐｔｅｒｉｓ－Ｐｈｏｅｎｉｃｏｐｓｉｓ植物群，时代为中侏罗世。

The Datong Formation of Ningwu Coalfield is composed mainly of yellowish green or greyish green sandstone, silty mudstone, siltstone and mudstone, intercalated with limestone beds and coal seams, ranging from the top of red mudstone of the Tongchuan Formation to the bottom of greyish green sandstone of the Yungang Formation, 283-416m thick, which was deposited in the lake to lake-delta environments. This Formation contains very abundant land plant fossils, grouping into the Coniopteris-Phoenicopsis Flora of Middle Jurassic age.