摘要
位于滇东南老君山Sn-W多金属矿集区的南秧田钨矿是云南省境内规模最大的钨矿床。该矿床是否存在受控于印支期区域变质和燕山期岩浆-热液活动的多期叠加成矿作用是目前亟待解决的科学问题。本文通过对南秧田钨矿床不同矿化类型中的主要硫化物进行原位微量元素及S同位素分析,识别多类型矿化物质来源以及成矿物理化学条件差异。硫化物的S同位素组成(δ^(34)S值主体介于4‰~10‰)以及黄铁矿中普遍较高的Se/S值表明,矽卡岩型矿化和热液石英脉型矿化成矿物质来均来自岩浆。硫化物中较低的Co/Ni值(<1)表明流体在上升过程中遭受了较强的地层物质混染。不同矿化类型中的黄铁矿和磁黄铁矿具有较明显的微量元素组成差异,显示石英脉型矿化流体相较于矽卡岩矿化流体具有较低的温度、盐度以及较高的氧逸度,反映成矿过程中可能存在大气水的混入,为同一岩浆-热液体系在不同阶段的体现。
The Nanyangtian W deposit,located in the Laojunshan Sn-W polymetallic ore district,is the largest W deposit in Yunnan Province.Whether the deposit has the multi-stage superimposed mineralization governed by the Yanshanian magmatic-hydrothermal activity and Indosinian regional metamorphism is a key scientific problem to be resolved urgently.The material sources of multiple types of mineralization and the variations in metallogenic physical and chemical conditions for the Nanyangtian W deposit have been identified in this work by using in-situ analyses of trace elements and sulfur isotopes of primary sulfides of different types of mineralization in the deposit.The consistent S isotopic compositions of sulfides(withδ^(34)S values mainly between 4~10‰)and the general relatively high Se/S values of pyrites suggest that ore-forming materials of both the hydrothermal quartz-vein-type mineralization and skarn-type mineralization was sourced from magma.The relatively low Co/Ni(<1)ratios of sulfides indicate that the fluid was contaminated by materials of strata in the upward migration process of fluid.Pyrites and pyrrhotites in ores of different mineralization types have obvious different compositions of trace elements,indicating that the ore-forming fluid of the quartz veintype mineralization has relatively low temperature,salinity,and relatively high oxygen fugacity than that of the skarn mineralization,this is probably attributed to the involvement of meteoric water in the mineralization process of the deposit.The skarn mineralization and quartz vein–type mineralization could represent different mineralization stages of the same magmatic–hydrothermal system.
作者
张庆鸽
赵晓瑜
邓明国
李文昌
陈应华
ZHANG Qing-ge;ZHAO Xiao-yu;DENG Ming-guo;LI Wen-chang;CHEN Ying-hua(Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China)
出处
《矿物岩石地球化学通报》
北大核心
2025年第3期646-661,共16页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
云南省重大科技专项计划支持项目(202202AG050006)
国家自然科学基金资助项目(42103062)
云南省基础研究专项支持项目(202201AU070141)
昆明理工大学人培基金资助项目(KKZ3202021041)。
关键词
滇东南
南秧田钨矿
硫化物
微量元素
S同位素
southeastern Yunnan
Nanyangtian tungsten deposit
sulfides
trace elements
sulfur isotope
