对相山西部“倒转地层”成因的探讨  

The reason of“overturned stratum”in west of Xiangshan Area

作　　者：魏欣 许健俊 聂涛 WEI Xin;XU Jian jun;NIE Tao(Research Institute No.270,CNNC,Nanchang 330200,Jiangxi,China;Jiangxi Mining and Metallurgy Bureau of Nuclear Industry,Nanchang 330200,Jiangxi,China)

机构地区：[1]核工业二七○研究所地质勘查院,江西南昌330200 [2]核工业江西矿冶局,江西南昌330200

出　　处：《矿产勘查》2024年第S01期273-282,共10页Mineral Exploration

基　　金：核工业地质局“江西省相山矿田及邻区铀矿资源调查评价与勘查”项目(202229)资助。

摘　　要：相山西部部分地区存在一种由浅入深呈“碎斑熔岩-流纹英安岩-碎斑熔岩-流纹英安岩”的火山岩地层顺序现象,这种现象与相山西部正常的碎斑熔岩覆于流纹英安岩之上相悖。对此,前人认为上层流纹英安岩或下层碎斑熔岩是后期侵入而形成的斑岩。本文通过对不同层位碎斑熔岩和流纹英安岩的结构构造特征、化学组成研究,结合对上、下两层流纹英安岩中锆石U-Pb同位素年龄测定,认为上、下两层流纹英安岩与区内其他流纹英安岩是同期同源岩浆喷发形成的产物;上、下两层碎斑熔岩与区内其他碎斑熔岩也是同期同源岩浆喷发形成的产物。倒转地层近似线状展布的原因可能与相山西部基底深大断裂相关。There is a appearance in west of Xiangshan area,which is stratum presented“porphyroclastic lavarhyodacite lava-porphyroclastic lava-rhyodacite lava”.This is contradiction with normal appearance.In the past,the explanation is upper rhyodacite lava or lower porphyroclastic lava is intrusive rock.In this study,we collected samples from the upper and lower layers of porphyroclastic.LA-ICP-MS zircon U-Pb isotope dating has been conducted on thses samples.Combined with the studying the textural and structural characteristic of different rhyodacite lava and porphyroclastic lava,we propose the upper and the lower rhyodacite lava both are derived from same source at same time,the upper and the lower porphyroclastic lava also both are derived from same source at same time.The appearance of“porphyroclastic lava–rhyodacite lava-porphyroclastic lava-rhyodacite lava”is presented liner maybe related to a major disruption.This disruption is located in deep schist.

关 键 词：相山 流纹英安岩 碎斑熔岩 基底断裂 

分 类 号：P619.14[天文地球—矿床学]