地质学报2017，Vol.91Issue(3)：542-560,19.
内蒙古白乃庙铜-金-钼矿床成矿机制——来自流体包裹体和He-Ar同位素的证据
Mineralization Mechanism of the Bainaimiao Cu-Au-Mo Deposit in Inner Mongolia:Evidence from Fluid Inclusions and He-At Isotopes
摘要
Abstract
The Bainaimiao Cu-Au-Mo deposit is an important ore deposit in the middle section of the north margin of North China Block,and its mineralization is characteristic of both porphyry alteration and distinct post-orogenesis transformation.Systematic study of fluid inclusions was carried out using microthermometry,laser Raman and chromatography methods.The results suggest that the ore-forming fluid was a middle-low temperature,low salinity CO2 (CO)-H2 O-CH4 (C2 H2 +C2 H4)-NaCl-CaCl2 system,with fluid mixing and CO2 escaping being the leading factors for mineralization.Rich reducing fluid may result in that large volume of vapor fluid carrying ore-forming elements such as Cu,Au migrated to distant Bainaimiao Group and precipitated along the foliation or fissures.The 3He/4He and 40Ar/36 Ar values (3He/4He=0.06～0.71 Ra,and 40Ar/36 Ar=375.5 ～ 1436.3,respectively) of the fluid inclusions in pyrites from the different mineralization phases in the Bainaiiao deposit suggest that the ore-forming fluid system was mixed by the fluids of two end members,one is the high temperature deep-derived fluid congeneric with the porphyries generated by crust-mantle mixing;the other is the low-temperature meteoric water which is rich in crustal radiogenic He with the component of atmospheric Ar.It can be concluded that the Bainaimiao deposit belongs to the porphyry-type Cu-Au-Mo deposit that underwent the late orogenic transformation,and formed in the background of the continuous southward subduction of paleo-Asian ocean plate.关键词
He-Ar同位素/还原性流体/叠加改造/白乃庙铜-金-钼矿床/内蒙古Key words
He-Ar isotope/reducing fluid/superimposed reformation/Bainaimiao Cu-Au-Mo deposit/Inner Mongolia引用本文复制引用
周振华,车合伟,欧阳荷根,马星华..内蒙古白乃庙铜-金-钼矿床成矿机制——来自流体包裹体和He-Ar同位素的证据[J].地质学报,2017,91(3):542-560,19.基金项目
本文为中央级公益性科研院所基本科研业务费项目(编号K1314)、中国地质大调查项目(编号12120113093600)和国家自然科学基金项目(编号41302061)资助的成果. （编号K1314）
