重力方法研究河南区域构造及控煤作用

Tectonics and Its Coal-controlling Process Investigation through Gravitational Surveying in Henan

河南地区存在三个明显的重力异常区,与其区内三个次一级的构造分区相一致,其重力异常曲线的挤压扭曲特征、剪切平移特征、张性舒展特征分别对应构造挤压变形机制、平移剪切机制及变形拉张机制。这些变形受印支、燕山及喜马拉雅期三大构造运动控制,其中印支期剥蚀及沉降程度是构成现今煤层埋藏条件的重要因素,燕山期形成河南煤田的逆冲推覆型控煤构造,喜马拉雅期构造运动,最终确立了河南煤系的展布范围及赋存状态,这表明控煤模式是构造运动的结果。

Three evident gravitational anomaly areas are existed in Henan area. In accordance with secondary tectonic zonation in the area, gravity anomaly curves＇ compressing and distorting, shearing and translating, tensional extending characteristics are respectively corresponding to compression deformation, translational shear and deformational extension mechanics of tectonics in Henan. These deformations were controlled by Indo-China, Yanshanian and Himalayan movements. In which, denudation and subsidence extents during Indo-Chinese stage are major factors to form present coal seam burying conditions, coal controlling thrusting nappe structures in Henan coalfields were formed in Yanshanian stage, while tectonic movements during Himalayan stage finally established coal measures distrbution extent and hosting state in Henan. All of these demonstrated that the coal controlling pattern is in consequence of tectonic movements.