西藏斯弄多银多金属矿床典中组板岩地球化学特征及地质意义  

Geochemical characteristics and geological significance of the Dianzhong Formation slate from the Sinongduo Ag polymetallic deposit,Xizang

作　　者：黄一入 唐菊兴[2] 杨宗耀 钟庆伟 张鹏 HUANG Yiru;TANG Juxing;YANG Zongyao;ZHONG Qingwei;ZHANG Peng(School of Air Traffic Management,Civil Aviation Flight University of China,Guanghan 618307,China;Institute of Mineral Resources,CAGS,Beijing 100037,China;Sichuan Geological Big Data Center,Chengdu 610072,China;Chengdu Surveying Geotechnical Research Institute Co.,Ltd.of MCC,Chengdu 610023,China;Sichuan Academy of Land Science and Technology,Chengdu 610074,China)

机构地区：[1]中国民用航空飞行学院空中交通管理学院,四川广汉618307 [2]中国地质科学院矿产资源研究所,北京100037 [3]四川省地质大数据中心,四川成都610072 [4]中冶成都勘察研究总院有限公司,四川成都610023 [5]四川省国土科学技术研究院,四川成都610074

出　　处：《沉积与特提斯地质》2024年第4期710-722,共13页Sedimentary Geology and Tethyan Geology

基　　金：国家自然科学基金(42230813);四川省自然科学基金(2022NSFSC1902);四川省科技计划资助项目(2023NSFSC0753);中央高校基本科研业务费专项资金项目(24CAFUC04029)。

摘　　要：林子宗群是印度-亚洲大陆汇聚的重要产物,主要为一套火山岩和少量沉积岩,本次在斯弄多银多金属矿床林子宗群火山岩系的典中组中发现了大量板岩,为了研究其成因及对成矿作用的指示,对斯弄多典中组板岩开展了岩石学和全岩地球化学研究,结果显示:斯弄多典中组板岩与火山岩呈渐变接触关系,且与火山岩的大部分主量、稀土和微量元素地球化学组成相似,而不同于沉积成因的板岩。但同时,与典中组火山岩相比,典中组板岩的亚铁和As含量明显增高,虽然沉积成因的板岩As含量同样较高,但其亚铁含量却较低,亚铁和As没有明确的关系。结果表明,斯弄多典中组板岩的原岩为典中组酸性火山岩,由典中组火山岩与后期岩浆热液发生接触热变质而形成,并促进火山岩中金的富集,因此区域低温变质作用可能是典中组火山岩形成金矿的必要条件。The Linzizong Group is an important product of the India-Asia continental convergence,primarily consisting of a suite of volcanic rocks and a small amount of sedimentary rocks.In this work,a significant amount of slate was discovered in the Dianzhong Formation of the Linzizong Group volcanic rocks from the Sinongduo Ag polymetallic deposit. In order to study the origin of the slate and its indications for mineralization, petrological and whole-rock geochemical studies were carried out on the slate. The results show that the slate exhibits a gradual contact relationship with the Dianzhong Formation volcanic rocks and has a similar geochemical composition of most of the major, rare earth, and trace elements of the volcanic rocks, which is different from that of the slate of sedimentary origin. However, the sub-iron and arsenic contents of the slate are significantly higher than those of the Dianzhong Formation volcanic rocks. Although the arsenic contents of the slate of sedimentary origin are similarly high, there is no clear relationship between the sub-iron and arsenic contents. The results suggest that the protolith of the slate from the Sinongduo Ag polymetallic deposit is the Dianzhong Formation acidic volcanic rocks, and was formed by the metamorphism of the Dianzhong Group volcanic rocks through the reheating of the later magmatic events, contributing to the enrichment of gold in the volcanic rocks. Regional low temperature metamorphism may be a necessary condition for the formation of gold ores in the Dianzhong Formation volcanic rocks.

关 键 词：变质作用 地球化学 板岩 林子宗群 火山岩 金成矿作用 

分 类 号：P595[天文地球—地球化学] P618.51[天文地球—地质学]