准格尔煤田老三沟井田构造特征及其成因讨论

ZHUNGEER coalfield third ditch minefield structural features and causes

通过对准格尔煤田老三沟井田三维地震勘探及构造地质分析,依据断层规模本文将断层分为三级,其中一级断层(DF48)形成于早白垩世区域近东西向伸展应力背景下,二级与三级断层是由于煤系地层基底的起伏不平,导致的同沉积或差异压实作用造成的断层。地质异常体依据其性质与成因可分为三类:疑似陷落柱、塌陷及沉积凹陷,前两者与陷落柱成因相似,是由煤系之下碳酸盐岩弱溶蚀作用造成的规模较小的陷落柱,而凹陷是由于煤系地层沉积时古地形局部高低不平的形态造成的,并非后期构造引起。

Through the 3D seismic detection and structural geology analysis on the Laosangou well field lo-cated in Zhungeer coal field, this paper classifies the faults into three levels based on their size. The first level fault （DF48） was formed under the regional stretching stress in an E - W direction in early Cretaceous. Both the second level fault and the third level fault are the results of syndeposition or differential compaction which is caused by the uneven base of the coal - bearing strata. The geological anomaly could be divided into three cate- gories according to their features and origins, namely suspected collapse column, subsidence and delapsional deposit. Similar as collapse column, the first two categories are caused by weak dissolution effect of carbonate rocks in coal - bearing strata and could be recognized as relatively small - sized collapse column. The form of delapsional deposit, however, is attributed to locally uneven ancient landform during the sedimentary of coal - bearing strata, rather than post tectonic.