柴达木盆地北缘构造分区与煤系赋存特征

TECTONIC DIVISIONS AND DISTRIBUTION RULES FOR COAL MEASURES IN NORTHERN QAIDAM BASIN

柴达木盆地北缘煤炭资源丰富,煤系赋存受构造格局控制明显。本文立足于煤田构造特点分析,结合煤系基底构造特征、主干断裂构造特征及煤系赋存特征分析,建立了柴北缘煤田构造单元划分方案,将柴北缘含煤区划分为3个三级构造单元和11个四级构造单元。以此为依据,讨论了构造格局对煤系赋存状况的控制。印支期后多次大规模的构造运动,使得煤系展布呈现出南北分带、东西分区的基本规律。三条隆起带南麓,受逆冲推覆构造作用,含煤地层抬升变浅,但多遭受剥蚀;三条凹陷带内煤系广泛分布,浅部可形成较大面积的有利勘探开发区块,成为柴北缘预测找煤的重点区域。

The northern Qaidam Basin is enriched in coal resources, which were obviously controlled by the structural framework. Based on an analysis of the characters of the coalfield structures, basement structures, main faults, and the distribution conditions of coal measures in northern Qaidam Basin, the authors brought forward a scheme of division for the coalfield tectonic units, which can be divided into 3 third-level units and 11 fourth-level units. According to the tectonic divisions in northern Qaidam Basin, the structural framework that controls the distribution of coal measures was discussed. After several episodes of regional tectonic activities since the Indosinian, zonation from the north to south and regionalization from east to west were formed in terms of distribution of coal measures. Affected by the thrust and nappe structures, the coal measures were raised to shallow surface, with abundant denudation occurring in the south part of the three uplift belts. As coal measures were extensively distributed in the three depressions, areas favorable for commercial coal exploration and development can be predicted in the shallow parts of the depressions, as they can be preferred targets for coal resources surveying in northern Qaidam Basin.