Er＇lian basin group is the biggest late Mesozoic basin group in Inner Mongolia,and Duhumu basin is one of the basins which are rich in coal resources.Coal-bearing strata are located in the fifth section of Cretaceous Yanhua formation.Coal quality is lignite with mellow lime,high sulfur,high calorific value,low-medium phosphorus and low chloride.Structures in this area are very simple.Saihantala coal field which is controlled by Haolai-Xilinhuduge fault has been naturally divided into several coal accumulating basins with unequal scale.Magmatic rocks in the marginal areas of this basin developed well.It is mainly composed of intrusive rocks in late Variscan and early Yanshan period.Its rock property is super-basic to acid,and generally occurred as county rocks.Coal strata were formed by the sedimentary combination type which was controlled by flooding and the sedimentary facies based on shallow water gravity flow and peat swap sediments.Sedimentary environment can control the distribution of rich coal belt.The main coal accumulation occurred in late basin developing period.The coal-rich belt was located in the northwest side of the basin-controlling fault with the distance of 2~4km.%二连盆地群是内蒙古自治区最大的一个晚中生代盆地群,都呼木盆地是其中之一富煤盆地,含煤层位于白垩纪彦花组第五段,煤层的煤质为中灰、中高硫、高发热量、低磷—中磷低氯的褐煤,受好来-锡林呼都格断裂控制形成的赛罕塔拉煤田,自然分割成了若干个规模不等的聚煤盆地。盆地边缘地区岩浆岩发育,以华力西中晚期、燕山早期侵入岩为主,岩性从超基性—酸性,一般呈岩基产出。煤层形成于漫流为主的沉积组合类型和浅水重力流和泥炭沼泽沉积物为主的沉积相。沉积环境对富煤带展布起控制作用,该区主要聚煤作用发生在盆地发育的晚期,富煤带在控盆断裂的西北一侧2～4km附近。
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