西北地区与锡成矿有关的花岗岩特征及成矿  

The Characteristics of Granite Associated with Tin and Mineralization in Northwest China

作　　者：彭素霞 郭玉 张照伟 全孝勤 陈博 谢春林 PENG Suxia;GUO Yu;ZHANG Zhaowei;QUAN Xiaoqin;CHEN Bo;XIE Chunlin(Xi'an Center of China Geological Survey/Northwest China Center for Geoscience Innovation,Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits,MLR,Xi'an 710119,Shaanxi,China;The Second Senior Middle School of Xihua County,Henan Province,Zhoukou 466600,Henan,China;China General Administration of Metallurgical Geology Northwest Geological Survey,Xi'an 710119,Shaanxi,China)

机构地区：[1]中国地质调查局西安地质调查中心/西北地质科技创新中心,自然资源部岩浆作用成矿与找矿重点实验室,陕西西安710119 [2]河南省西华县第二高级中学,河南周口466600 [3]中国冶金地质总局西北地质勘查院,陕西西安710119

出　　处：《西北地质》2024年第5期27-39,共13页Northwestern Geology

基　　金：国家重点研发计划课题“中亚成矿域战略性矿产信息及成矿规律”(2021YFC2901802);中国地质调查局项目“阿尔泰-准噶尔北缘成矿带战略性矿产调查”(DD20240073)联合资助。

摘　　要：西北地区是国内成矿条件优越、矿产资源集中区域之一,但锡产出不足全国的2%,且分布零散、规模较小,所以西北地区锡矿并没有得到很多关注,且已有研究主要偏重典型矿床的地球化学分析和矿床成因,对区域成矿特征和成矿规律少有总结。笔者选择西北地区与锡有关的花岗岩为研究对象,通过分析此类花岗岩的特征提出锡矿找矿新认识。分析显示,Sn元素易富集于晚期熔体,且易由地幔向地壳富集,花岗岩浆源区地壳物质越多对形成锡矿越有利,A型花岗岩对锡成矿有更为明显的专属性,尤其在大陆碰撞、俯冲和洋陆转换环境下形成的过铝质和钙碱性花岗岩更有利于锡富集。同时,与锡成矿有关的花岗岩普遍具有较高锡丰度,如东准和天山地区达到7×10^(-6),远远高于地壳Sn丰度值(1.7×10^(-6)),加之成矿区地层锡值普遍偏高,锡经过不断的迁移、富集、岩浆结晶分异并在一定的温度下最终成矿。文中简述了西北地区的6个锡矿成矿区带特征,为西北地区锡矿找矿提供参考。Northwest China is one of superior conditions area for tin ore formation and rich mineral resources in China,but tin ore output is less than 2%,and scattered distribution and small scale in the area.Because tin is not a dominant mineral,it has not received much attention.Previous research mainly focused on the geochemical and genesis of typical deposits,lacking a summary and understanding of regional mineralization characteristics and patterns.This paper selects the granite related to tin ore as the research object.The authors put forward some new comprehension of tin prospecting by analyzing the characteristics of the granite.The paper shows that tin is not only enriched in late melt but also from mantle to crust.The more crustal material in granulite basement,it is the more favorable for tin mineralization.A-type granite has a more obvious specificity to tin mineralization.It found that granites related to tin mineralization generally have higher Sn abundance,especially the peraluminous and calc-alkaline granites formed in the environment of continental collision,oceanic or crust subduction and ocean-continent transition are more conducive to tin enrichment.The high Sn abundance is also an essential factor for tin mineralization.For example,in the East Junggar and Tianshan regions,the tin abundance is reached 7×10^(-6),higher than the crustal tin abundance value of(1.7×10^(-6)).Tin ore is finally formed at a certain temperature,continuous mobilized,migrated,enriched,and magmatic crystallization differentiation.Based on the above views,the paper describes the characteristics of the 6 tin metallogenic belts in Northwest China,which are considered to be tin prospecting potential area.

关 键 词：锡矿 与锡有关花岗岩 成矿条件 成矿环境 西北地区 

分 类 号：P618.2[天文地球—矿床学]