lower permian series

基本解释

The major reason for natural gas accumulated in Upper Shihezi Formation and Shiqianfeng Formation may be related to gas migration in "chimney" style from Lower Permian series.
上石盒子组-石千峰组天然气聚集的主要原因可能与天然气的“烟囱式”运移有关。
The pyrite deposit in Huangchangping, Jianshi appears stratified(in ore beds)or stratoid(in bedded vein)occurring at the lower part of Wujiaping Formation of the upper series of Permian System;
本文介绍了川东—鄂西与毗邻地区二叠系上统吴家坪组黄铁矿床的特征、分布规律；
The Lower Carboniferous Ceshui and Upper Permian Longtan coal series are most important in Southeast China, and can both generate and bear gas greatly in the Lianyuan coal basin, Central Hunan, China.
湘中涟源煤盆地早石炭世测水组、晚二叠世龙潭组煤系是中国东南诸省境内最重要的煤系，具有较大的生气、储气能力。