投稿时间：2012-03-06
修订日期：2013-01-05
中文摘要:福建马坑矿床是一个大型层控矽卡岩型铁(钼)矿床,赋存于早白垩世莒舟-大洋花岗岩外接触带黄龙组灰岩和林地组碎屑岩层间构造破碎带中。对不同成矿阶段的石榴子石、透辉石、角闪石、石英、方解石和萤石中流体包裹体所进行的岩相学和显微测温研究表明, 与成矿有关的包裹体类型主要有富气相水溶液包裹体、富液相水溶液包裹体、含子矿物多相包裹体和少量富CO2包裹体,其中以富液相水溶液包裹体为主。气相组成均以CO2、H2O、N2、O2为主,其次为CH4、C2H4、C2H6和少量C2H2,液相成分中阳离子以Na+、K+和Mg2+为主,其次为Ca2+和少量Li+,阴离子以SO2-4、F-、Cl-为主,还含有少量Br-、NO-3,成矿流体应为H2O-NaCl(NaF)±CaCl2(KCl)体系。矽卡岩、退化蚀变、石英硫化物阶段均一温度分别为460~600℃、260~540℃、160~400℃;盐度w(NaCleq)分别为(6%~24%、32%~44%),(4%~16%、36%~44%)和0~4%。H、O、C、S同位素研究表明,矽卡岩期成矿流体主要是岩浆水,晚期石英硫化物阶段混有不同程度的大气降水,流体中碳和硫来自深部或地幔,但也受到围岩等因素的影响。岩浆热液的相分离及其与大气降水的混合作用可能是马坑铁(钼)矿床形成的主要原因。
Abstract:The Makeng Fe-Mo deposit is a large skarn-type magnetite deposit hosted in interlayer fractures between carbonates of Huanglong Formation(C2h) and clastic rocks of Lindi Formation(C1l) at the exo-contact zone of the Juzhou-Dayang granite. Petrographic and microthermometric studies of fluid inclusions in garnet, diopside, hornblende, quartz, calcite and fluorite of different ore-forming stages show that the inclusions related to mineralization include mainly vapor-rich liquid inclusions, liquid-rich liquid inclusions, daughter mineral-bearing inclusions and CO2-rich inclusions, in which the liquid-rich inclusions are dominant. Gas components of fluid inclusions are mostly CO2, H2O, N2 and O2, followed by CH4, C2H4 and C2H6, with a small amount of C2H2, Cations of liquid components are mainly Na+, K+ and Mg2+, followed by Ca2+, with a small amount of Li+, while anions are mainly SO42-, F- and Cl-, followed by Br- and NO3-. Homogenization temperatures of these ore-forming stages are from early to late 460~600℃, 260~540℃ and 160~400℃ respectively, whereas salinities are (6~24%, 32~44%), (4~16%, 36~44%) and (0~4% ), respectively. H, O, C and S isotopic geochemistry shows that the early ore-forming fluids of the skarn stage were mainly derived from magmatic water, whereas the late fluids of the quartz-sulfide stage were mixed with the meteoric water in varying degrees, and that the carbon and sulfur in the fluids were mainly derived from the mantle or a deep-seated place, with some contributions made by other factors such as surrounding rocks. Phase separation of magmatic water and fluid mixing with meteoric water as well as buck boiling might have been the main factors responsible for minera-lization.
keywords:geochemistry fluid inclusions stable isotope iron (molybdenum) skarn deposit Makeng Fujian Province
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中图分类号：618.31;618.65
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基金项目:本文为国家重点基金项目"华南地区中生代板内成矿作用及其动力学背景(编号: 40930419)";中央高校基本科研业务费专项资金(编号: 2011PY0158)和成矿作用与资源评价重点实验室开放研究项目(编号: ZS1104)资助成果
引用文本：
张承帅,毛景文,张长青,于淼.2013.福建马坑矽卡岩型铁(钼)矿床流体包裹体特征及成矿机制研究[J].矿床地质,32(2):289~307ZHANG ChengShuai,MAO JingWen,ZHANG ChangQing,YU Miao.2013.Fluid inclusion characteristics and metallogenic mechanism of Makeng skarn Fe-Mo deposit in Fujian Province[J].Mineral Deposits32(2):289~307
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