| 内蒙古东部晚中生代断陷煤盆地与伸展构造 |
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| 引用本文：.1994.The late Mesozoic fault coal basins and the stretching structure ln eastern Inner Mongolia[J].Mineral Deposits,13(3):212~220 |
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| 中文摘要:晚侏罗世晚期至早白垩世，内蒙古东北部出现了一个裂陷作用期，形成大量地堑、半地堑式断陷盆地，盆地之边缘为犁式正断层，部分可能是剥离断层，它们是伸展作用下的产物。在统一的区域伸展作用下形成的多数盆地具有一定类似的构造、地层及煤层格架，以及具有可比的沉积组合所构成的盆地充填序列。犁式正断层发育的全过程控制了盆地的形成和演化，也控制了煤层的展布方向、煤体的横向分带和纵向分区、煤层旋回结构及煤变质程度。 |
| 中文关键词:伸展构造 犁式正断层 煤盆地 内蒙古 |
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| The late Mesozoic fault coal basins and the stretching structure ln eastern Inner Mongolia |
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| Abstract:Petroleum deep drilling, coal investigation and deep geophysical study performed in the past ten years or more show that from Late Jurassic to Early Cretaceous in Inner Mongolia, there occurred an important rift faulting period during which the crust obviously became thinner, and the mantle uplifted, forming a great number of graben or semi-graben style fault basins, with plough-shaped normal fault (which might be partly exfoliation faults) rimming them. Such a tectonic pattern is quite similar to the tectonics in the basin-mountain area of West America, both being products of stretching. The plough-shaped normal faults played a leading role in controlling the geometric forms, sedimentary environments, coal seams and coal quality. Most basins formed under the unified regional stretching have somewhat similar tectonic, stratigraphic and coal seam framework as well as basin deposition sequences composed of comparable sedimentary associations. Stretching led to the formation of plough-shaped normal faults, while tile whole process of fault development controlled the formation and evolution of the basins and the accumulation of coal. The extension directions of the faults decide the distribution of the basins, the lengths of the faults decide the lengths of the basins, the amplitude of the fault movement decides the width and depth of the basins, and the frequency of the fault movement decides the structure of coal-measures and coal seams. Under the conditions of slow downglide motion and favorable paleogeographic and climate conditions, the velocity of subsidence was a bit lower than that of the accumulation of coal-forming materials, resulting in the formation of great thickness of coal seams. The plough-shaped normal faults of synsedimentary character played an important role in controlling the spreading direction of coal seams, the sedimentary environment during the formation of coal seams, the transverse zoning and the longitudinal division of coal bodies, the cyclic structure of coal seams and the degree of coal metamorphism． |
| keywords:stretching structure, plough-shaped normal fault, coal basin, Inner Mongolia |
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