广旺矿区大倾角地层中隐伏古岩溶陷落柱的形成机理及时间

Formation Mechanism and Time of Buried Paleokarst Collapse Column in Steeply Dipping Strata in Guangwang Coal Mine Area

大倾角地层中的古岩溶陷落柱,是一种特殊的地质现象,如果不作综合地细致研究,容易产生误判为断层的可能。从广旺煤矿区的基本地质情况入手,立足于地壳升降运动是陷落柱形成的主要动力来源,通过对区域地质构造的演化与区域地层的对应关系,分析阐明了大倾角地层中古岩溶陷落柱的形成机理,以及对形成和定型时间的厘定。分析认为广旺煤矿区大倾角地层中的古岩溶陷落柱形成的基本条件和形成的初期机理,与一般地层中发育的陷落柱是一致的。其最终成型,相较于水平或缓倾斜地层中的陷落柱,是在地质构造运动的叠加作用下,增加掀斜过程。其起始发育于中侏罗世和早白垩世早期,于始新世晚期完全停止发育,直至定型。

Paleokarst collapse column in steeply dipping stratum is a special geological phenomenon,which may be misjudged as fault if it is not studied comprehensively and carefully.Starting with the basic geological characteristics of Guangwang coal mine area,based on the fact that the crustal movement is the main power source for the formation of collapse columns,through the evolution of regional geological structure and regional strata,this paper analyzes the formation mechanism of paleokarst collapse columns in steeply dipping strata and the determination of formation and finalization time.The analysis shows that the basic conditions and initial mechanism of the formation of paleokarst collapse columns in steeply dipping strata in Guangwang coal mine area are consistent with the collapse columns developed in general strata.Compared with the collapse column in horizontal or gently inclined strata,its final formation is an increasing tilting process under the superposition of geological tectonic movement.It developed in the Middle Jurassic and early Early Cretaceous,and completely stopped in the late Eocene until it was finalized.