甘肃北山地区下白垩统含煤地层沉积盆地及含煤性研究

COAL-BEARING PROPERTY OF LOWER CRETACEOUS COAL BASIN IN BEISHAN AREA, GANSU PROVINCE

通过对已完成勘探工作的吐鲁—驼马滩盆地和公婆泉盆地的资料分析研究,结合岩石学特征,对沉积旋回、沉积环境分析,认为下白垩统含煤沉积盆地是在印支运动及其以前发生的历次运动形成的复杂结晶基底上形成的内陆型沉积盆地,以NE向和NW向构造为主。含煤地层为下白垩统老树窝群下岩组,为一套内陆河流—沼泽碎屑岩含煤建造,旋回结构较为明显,属河流相序含煤建造的旋回结构。煤层多,厚度变化较大,煤层结构为较复杂含煤系数在5%~10%之间,煤质以褐煤为主。

Coal bearing strata developed well in Beishan area of Gansu. The characteristics of deposit environment and sedimentary cycle was analyzed in this paper based on the data of petrology and prospecting from Tulu-Tuomatan Basin and Gongpoquan Basin. It shows that the early cretaceous coal basin which was occurred on crystalline basement formed in the Indosinian and before, was a continental sedimentary basin, and the principal structure of this area is in NE and NW. Coal-bearing strata belong to Lower Cretaceous Laoshuwo group, which deposited mainly bearing coal construction clastic rocks of fluvial-swamp facies, and the cycle architecture developed well in the group. Coal seams were characterized by excessive, complicated, and varied thickness. The coal-bearing coefficient is around 5%-10%, and the coal was classified into lignite.