地质学报2017，Vol.91Issue(10)：2240-2255,16.
广东韶关市一六钨矿床流体包裹体特征及成矿作用
Characteristics of Fluid Inclusions of the Yiliu Tungsten Deposit in Shaoguan, Guangdong Province and Implications for Metallogenesis
摘要
Abstract
The Yiliu tungsten deposit,tectonically located in the southern margin of the central Nanling metallogenic belt and in the southwestern margin of the Quren basin in northern Guangdong,is one of the most important prospecting achievements of North Guangdong in recent years.It belongs to typical skarntype deposit,with ore bodies occurring in both skarn of the Upper Devonian Maozifeng Formation and NWW-trending K-feldspar-quartz-tungsten veins and mica-quartz veins.Based on field and microscope observations,this study divides the ore-forming process into skarn period (A) and hydrothermal period (B).The former is composed of early skarn stage (A1),late skarn stage (A2) and K-feldspar-quartztungsten stage (A3),whereas the latter is composed of mica-quartz vein stage (B1) and quartz-carbonate stage (B2).Four types of fluid inclusions have been identified:daughter mineral-bearing inclusions (type Ⅰ),gas-aqueous two-phase inclusions (type Ⅱ),three-phase CO2-aqueous inclusions (type Ⅲ) and pure CO2 inclusions (type Ⅳ).Type Ⅰ occurs only in A3 stage quartz.Type Ⅱ,type Ⅲ and type Ⅳ can be found in A3 and B1 stage quartz,whereas two-phase aqueous inclusions can be found in A3 and B1 stage tungsten.The homogenization temperatures of the type Ⅰ,type Ⅱ and type Ⅲl fluid inclusions in stage A3 vary from 162℃ to 381℃,154℃ to 363℃ and 290℃ to 390℃,respectively.The salinities of type Ⅰinclusions range from 30.1％ to 45.4％(wt％NaClequiv),while those of type Ⅱ and type Ⅲ range from 1.49％ to 11.0％ and 2.20％ to 6.88％.The homogenization temperatures of type Ⅱ and type Ⅲ fluid inclusions in B1 stage vary from 152℃ to 381℃ and 281℃ to 378℃,and the salinities of each type of inclusion ranges from 1.65％ to 9.32％ and 2.00％ to 8.82％.Raman spectroscopy shows that the fluid compositions are mainly H2O,CO2,CH4 with a little CO32-,indicating a reducing environment.Temperature-Salinity diagram of fluid inclusion data show three groupings.Zone "a" represents the originally high salinity exsolved fluid,zone "b" shows fluid immiscibility,and zone "c" shows the originally high salinity fluid mixed with lower salinity underground water.The fluid inclusions of each zone represent different evolutionary stages of primitive fluids which eventually formed the magmatic intrusion.The ore-forming pressures calculated using fluid inclusions of type Ⅰ range from 86.0 MPa to 415.8 MPa,and the pressures of A3 stage corrected using data from fluid inclusions of type Ⅱ and type Ⅳ range from 86 MPa to 115 MPa,while those in B1 stage range from 55 MPa to 93 MPa.The ore-forming temperatures in A3 and B1 stages vary from 176℃ to 279℃ and 162℃ to 228℃,the ore forming depth varies from 3.62 km to 4.26 km.This study shows that high pressure occurred locally at the early period of fluid evolution,and fluid immiscibility may occur earlier than fluid mixing and further promoted fluid immiscibility.Changes of the fluid's physical-chemical conditions,fluid immiscibility and fluid mixing may be the leading factors of tungsten precipitation.关键词
一六钨矿/矽卡岩矿床/流体包裹体/成矿流体/流体演化/成矿作用Key words
Yiliu tungsten deposit/skarn deposit/fluid inclusions/ore-forming fluid/fluid evolution/metallogenesis引用本文复制引用
唐一昂,和秋姣,赖健清,杨牧,梅嘉靖,刘启,吴剑,谌后成,郭兰萱,胡理芳..广东韶关市一六钨矿床流体包裹体特征及成矿作用[J].地质学报,2017,91(10):2240-2255,16.基金项目
本文为中国地质调查局“整装勘查关键基础地质研究”计划项目(编号12120114052701)、中南大学“创新驱动项目”(编号2015CX008)资助的成果. （编号12120114052701）
