钦-杭结合带南段韧性剪切带印支期活动记录:以防城—灵山断裂带为例  

Indosinian activity records of ductile shear zones in southern segment of QinHang combined belt:A case study of Fangcheng-Lingshan fault zone

作　　者：丁汝鑫[1,2] 邹和平[1,2] 劳妙姬[1,2] 杜晓东[1,2] 周永章[1,2] 曾长育[1,2] 

机构地区：[1]中山大学地球科学与地质工程学院,广东广州510275 [2]广东省地质过程与矿产资源探查重点实验室,广东广州510275

出　　处：《地学前缘》2015年第2期79-85,共7页Earth Science Frontiers

基　　金：国家自然科学基金项目(41102131;41372223);中央高校基本科研业务费专项资金资助项目(12lgpy22);中国地质调查局项目(1212011121064;资[2010]矿评01-15-33);中山大学青年教师起步资助计划项目(32110-3181401)

摘　　要：钦-杭结合带南段发育一系列北东走向的韧性剪切带,防城—灵山断裂带是其中非常重要的一条。综合不同尺度地质构造特征和千糜岩绢云母单矿物40 Ar/39 Ar测年结果,表明钦-杭结合带南段防城—灵山韧性剪切带印支期可能存在两期活动,一期为早三叠世,另一期为晚三叠世,早期活动导致近E-W向变形,晚期形成NE向右旋韧性剪切带。根据千糜岩绢云母40Ar/39Ar年龄数据分析,认为防城—灵山断裂带在印支期发生右旋剪切活动的具体年龄接近于(203.9±1.7)Ma。A series of NE-trending ductile shear zones formed in southern segment of Qin-Hang combined belt, and Fangcheng- Lingshan fault zone is a very important one among them. Comprehensive geological features of different scales and the 4o Ar/39 Ar dating results of sericite in fault zone indicate that there may have been two periods of fault activity in Fangcheng- Lingshan fault zone during the Indosinian Movement. One is the Early Triassic when the early activity led to nearly EW-trending deformation; the other is the Late Triassic when the late activity led to the formation of NE-trending dextral ductile shear zone. According to the 4o At/ 39Ar dating results, the accurate age of late activity is close to 203.9±1.7 Ma.

关 键 词：防城—灵山断裂带 印支期 韧性剪切带 

分 类 号：P588.145[天文地球—岩石学]