新疆北部准噶尔-东天山地区金矿床成矿流体主要特征

产于新疆北部准噶尔-东天山地区的金矿床,主要形成于石炭和二叠纪,与该区的碰撞造山作用发生时间、空间、地球动力学背景完全吻合,代表了新疆北部后碰撞构造-岩浆-成矿活动的产物。该区典型金矿床石英流体包裹体小,以气液包裹体为主,未见含子矿物包裹体,含CO_2包裹体相对小、少,流体的盐度低,流体的温度主要是中低温。相同类型金矿床成矿流体水的来源相近,不同类型金矿床水的来源不同。矿物中S、Pb同位素及黄铁矿和矿物包裹体流体中REE主要为深源,佐证了本区成矿物质金是深源,深源的金主要以金硫络和物形式向上迁移。流体中C为地幔与地层的混源,其中直接侵入于含炭碎屑岩建造的构造蚀变脉岩型金矿成矿流体中C主要为有机碳,凸显出本区沉积地层生物成因有机碳对深源的金在浅部的搬运及卸载成矿有重要作用。

The characteristics of ore-fluid of gold deposits in Jungger-East Tianshan Mountains area, Xingjiang

Gold deposits in the Junggar-Eastern Tianshan of North Xinjiang area,formed in Carboniferous and Permian which completely tallies with the post-collisional time,space and geodynamics background in this area,and represented a result of tectonicmagma-mineralization activity of the post-collision event as well.Fluid inclusion in quartz from the typical gold deposits is characterized by small size,predominant gas-liquid phase,rare daughter-mineral,and containing small and less CO_2 inclusions,while the oreforming fluid is low salinity and medium-low temperature.Same deposit type yields similar water-source of ore-forming fluid,whereas different type yields distinct water-source.Characteristics of deep-source S and Pb isotope from ore mineral and REE from pyrite and fluid inclusion prevent a deep-source ore-forming material.The gold element upwards moves in Au-S complex form.The C isotope shows that the carbon of fluid is derived from mixed source by mantle and strata,and that carbon of fluid from the structurally-controlled-altered-dyke type gold deposits occurred in carbonaceous clastic rocks is mainly organic carbon.It is obviously that the biogenic organic carbon derived from sedimentary strata in this area plays an important role on transportation and unloading of deepsource gold.