甘肃省榆中盆地沉积-构造特征及找煤方向

Sedimentary-Structural Features and Coal Prospecting Orientation in Yuzhong Basin, Gansu Province

榆中盆地是一个较为独立的、边缘由断裂构造控制的中、新生代陆内盆地,基底为前寒武系变质岩,盆内含煤地层为中侏罗统阿干镇组,为河流相沉积体系;含煤地层及煤层赋存主要受断裂构造控制,控煤构造样式主要有逆冲叠瓦型、背斜—断裂组合、半地堑型。通过对榆中盆地的地质条件进行研究,结合以往的找煤成果,该区找煤方向主要应以逆冲断层的上盘和正断层的下盘为主,推断在盆地的东南缘和羊寨拗陷为煤炭资源的有利地段,也是今后进行煤田地质勘探的重点区域。

The Yuzhong Basin is a rather independent Mesozoic-Cenozoic intracontinental basin with faulted structure controlled mar-gin. Basement is Precambrian metamorphic rocks;coal-bearing strata belong to the middle Jurassic Aganzhen Formation, a fluvial sedi-mentary system. Coal-bearing strata and hosting of coal seams are controlled mainly by faulted structures. Coal controlling structural patterns mainly have thrusting imbricate, anticline-fault assemblage, semigraben types. Through study on geological conditions in Yu-zhong Basin, combined with previous coal prospecting results have considered that the orientation of coal prospecting should give priori-ty to hanging wall of thrusts and footwall of normal faults. It is deduced that the southeastern margin of the basin and the Yangzhai de-pression are coal resources advantageous sectors, also the key areas to carry out coal geological exploration henceforth.