摘要
南岭地区的钨锡成矿作用与花岗岩岩浆活动有十分密切的关系。花岗岩的物源与成矿元素的初始富集、花岗岩的分异程度和花岗岩中流体性质与活动性集中体现了花岗岩对成矿的控制能力,即花岗岩的成矿能力。初步建立了南岭地区钨锡花岗岩的成矿矿物学研究体系。黑云母、榍石、锆石、锡石、金红石、黑钨矿、白钨矿和钨铁铌矿等是讨论的重点矿物,它们可用于判别花岗岩的成矿能力。首先以矿物晶体化学为基础,介绍了上述矿物在钨锡花岗岩中的岩相学特征、内部构造和矿物化学及其变化,并分别论证了花岗岩原始含矿性、花岗岩结晶演化和花岗岩中成矿元素活动性的矿物学标志;其次,系统对比了南岭地区三类钨锡花岗岩(准铝质含锡花岗岩、过铝质含锡花岗岩和过铝质含钨花岗岩)的成矿矿物学特征。以湖南骑田岭花岗岩复式岩体为实例,进行了芙蓉-菜岭含锡花岗岩和新田岭含钨花岗岩的成矿矿物学对比研究。前者以黑云母、榍石为典型含锡矿物,它们在流体富集阶段,经热液蚀变作用,导致锡的淋滤和结晶富集作用;后者则以出现岩浆白钨矿和黑钨矿为特征。提出的钨锡花岗岩成矿矿物学研究体系有助于深化矿床学研究和矿床勘探工作,并将在今后工作中进一步完善。
Tungsten-tin mineralizations in the Nanling Range are closely related to granitic magmatism. Ability of controlling the mineralization of granites （or ore-forming potential of granites） is simply revealed by （1） the sources of granites （or initianl W-Sn enrichment）; （2） differentiation degree of granites; and （3） nature and activity of fluids during granite evolution. This work aims to preliminarily establish a research system of ore-forming mineralogy for tungsten-tin granites in the Nanling Range. Biotite, titanite, cassiterite, rutile, wolframite, scheelite and wolframoixiolite are essentially useful minerals in clarifying the ore-forming potential of granites. On the crystal-chemical basis, these minerals are separately discussed by their petrographic, internal textural and chemical features. Criteria of these minerals as indicators of pricinple granite-related processes are presented for initial W-Sn enrichment in granites, crystallization of granite and hydrothermal mobility of ore-forming metals in late stage of granite differentiation. Features of ore-forming minerals are compared among three types of Nanling W-Sn granites （metaluminous tin granites, peraluminous tin granites and peralumnious tungsten granites）. Finally, a case study was made in the Qitianling granite complex, which is essentially composed of the Sn granites of Furong and Calling, and the Xintianling W granite. The Sn granites are characterized by biotite and titanite as Sn-bearing minerals, which suffured hydrothermal alteration, leading to tin leaching and subsequent crystallization of cassiterite. However, the Xintianling granite contains magmatic scheelite and wolframite. The mineralogical system of W-Sn granites helps to deepen metallogenic study and exploration of W-Sn deposits, and will be improved and perfected during the further researches.
出处
《高校地质学报》
CAS
CSCD
北大核心
2008年第4期485-495,共11页
Geological Journal of China Universities
基金
国家自然科学基金(40730423
40221301)
中国地质调查局调查项目"南岭重要金属矿床成矿机理研究和找矿潜力预测"(1212010632100)联合资助
关键词
南岭地区
钨锡花岗岩
成矿矿物学
成矿能力
the Nanling Range
W-Sn granites
ore-forming mineralogy
ore-forming potential
