宝清煤田七星河区沉积环境演化与聚煤规律

The Law of Depositional Environment Evalution & Coal Accumulation in Qixinghe Area of Baoqing Coalfield

七星河区位于宝清煤田南缘,区内存在5种等时界面,将含煤岩系分为6个成因单元10个亚单元。沉积环境演化经历了初始充填期、湖泊扩张期、湖泊收缩期、湖泊淤浅期和结束充填期5个阶段。区内主要的聚煤作用发生在湖泊淤浅期,聚煤有利部位位于废弃的扇三角洲体之上。

Qixinghe area lies in the southern margin of Baoqing Coalfield. There are five types of chronostratigraphic boundaries in the area. By the boundaries, the coal-bearing sequence is divided into six genetic strantigraphic units and further into ten subunits. The evalution of deposi-tional environment goes through five stages, i. e. beginning- filling, lacustrine expanding, lacustrine contracting, lacustrine shallowing and end-rilling period. The main coal accumulation took place in the lacustrine shalowing period and the best place of coal accumulation is on the abandoned fan-delta bodies.