云南泸水市压扭性构造对银厂坪白云岩岩溶系统发育控制作用  

Transpressional structure and its control on development of Yinchangping dolomite karst system in Lushui City,Yunnan

作　　者：吴继文 吴亮君 吕勇[2] 王璞珺[3] 周嘉铭[2] 林宇 潘明[2,4] 廖家飞[2] 孟庆鑫 WU Jiwen;WU Liangjun;LV Yong;WANG Pujun;ZHOU Jiaming;LIN Yu;PAN Ming;LIAO Jiafei;MENG Qingxin;无(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China;Institute of Karst Geology,CAGS/Key Laboratory of Karst Dynamics,MNR&GZAR,Guilin,Guangxi 541004,China;College of Earth Sciences,Jilin University,Changchun,Jilin 130061,China;Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650093,China)

机构地区：[1]中国地质大学(北京)地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质科学院岩溶地质研究所/自然资源部、广西岩溶动力学重点实验室,广西桂林541004 [3]吉林大学地球科学学院,吉林长春130061 [4]昆明理工大学国土资源工程学院,云南昆明650093

出　　处：《中国岩溶》2021年第5期793-804,共12页Carsologica Sinica

基　　金：国家自然科学基金项目(42001011);中国地质科学院岩溶地质研究所基本科研业务费项目(2020014,2020015);中国地质调查局地质调查项目(DD20190022)。

摘　　要：银厂坪岩溶系统由溶蚀洼地和溶洞系统组成,溶蚀洼地内发育15个规模和形态不同的落水洞以及多条溶沟。根据断层面擦痕反演构造应力张量和共轭剪节理反映的应力场特征,结合区域地质背景,认为研究区于始新世—早中新世主要受SEE-NWW向挤压和NNE-SSW向拉张应力场控制,形成NW向左旋压扭性构造,其几何学和运动学特征符合里德尔剪切模式。走滑拉分阶区所形成凹陷具有汇水功能,利于岩溶作用形成溶蚀洼地,内部发育的共轭节理交汇部位是良好的导水构造,叠加在走滑微拉分阶区内,促进白云岩溶蚀作用形成落水洞。地下岩层受构造挤压发生层间滑动形成微裂隙,经溶蚀扩大,形成顺倾斜岩层发育的岩溶洞穴。左行走滑断裂造成地表河流和山脊发生系统左旋位错,发育断层崖于山脚处形成倒石堆,在构造抬升和剥蚀作用下,岩壁不断后退,地下河频繁袭夺使早期溶洞成为干洞,现代地下河于斜坡下游通过地下河出口转为明流。In this study,we conducted a detailed geological and geomorphological survey into the Yinchangping karst system in the dolomite strata of the Shazipo Formation of the middle-upper Permian in Lushui City,western Yunnan.The Yinchangping karst system consists of karst cave system and karst depression where develop 15 sinkholes and many karst trenches with different size and shape.The results of the inversion of the structural stress tensor from the striation on the fault plane and the characteristics of the stress field reflected by the conjugate shear joint as well as the regional geological background,show that the study area is mainly controlled by SEE-NWW compression and NNE-SSW tension stress field during the eocene-early Miocene,forming a NW-direction(N330°)left transpressional structural system,the geometry and kinematic characteristics of which conform to the Riddle shear mode.The depression with the function of water catchment,formed by the NW-direction(N330°)left transpressional structural fault is conductive to the formation depressions by karstification.The intersection of conjugate joints developing in the dissolution depression is a good water-conducting structure which is superimposed in the strike-slip micro-stretching zone to promote dolomite dissolution to form sinkholes.The underground rock strata compressed by tectonic compression slip between the layers form the micro-cracks which are expanded by dissolution to form karst caves developing along inclined rock strata.The river and ridge are systematically left-lateral offset by the left-lateral strike-slip fault,developing the fault cliff and followed by scree accumulation at the foot of the mountain.Under the effects of structural uplift and denudation,the rock walls continue to retreat,and the early karst caves have transformed into dry caves from the frequent attacks of underground rivers.The modern underground river turns into an open current at the downstream of the slope through the underground river outlet.

关 键 词：云南泸水市 白云岩岩溶系统 压扭性构造 里德尔剪切 成因机制 

分 类 号：P588.24[天文地球—岩石学] P511[天文地球—地质学]