摘要
由于特殊的矿化组合与大地构造环境,尾亚地区向来为研究东天山地区的地质学家所重视,然而关于尾亚矿床本身的研究尚不多见,本文试图对该矿床的地质特征和成因做一初步剖析,以期抛砖引玉,弥补东天山地区矿床研究的空缺。在详细的野外地质工作基础上,系统归纳整理了该矿床的地质特征,通过对矿石特征的研究,厘定了矿床的3个主要矿化阶段:岩浆结晶分凝阶段(形成似层状、浸染状和块状矿石)、贯入阶段(形成贯入式块状矿石)和岩浆热液阶段(形成伟晶状矿石)。对含矿岩石和矿石矿物进行了地球化学研究,计算出成矿的物理化学条件。含矿辉长岩的成岩温度为1296～1009℃,压力为296MPa左右,氧逸度为10-5.62～10-7.43;成矿温度(硫化物)为571～449℃,硫逸度为10-19.35～10-19.77。该矿床属于与碱性超镁铁质_镁铁质杂岩有关的岩浆型矿床;矿床形成以岩浆分凝和贯入式为主,晚期出现少量岩浆热液作用,为一岩浆分异_贯入_热液型复成因矿床。
Host rocks of the Weiya V-Ti-magnetite deposit in Xinjiang are characterized by a set of Early Permian alkali-rich rock series called Weiya super-unit, and the direct ore-bearing rock is alkali gabbro. There are two ore types in the deposit, namely disseminated ore and massive ore. The disseminated ore may contain medium- to fine-grained homogeneous disseminated ore, stratoid ore and pegmatitic ore. REE patterns of ore minerals form different ore types show good consistency, suggesting that they are congenetic products. The pegmatitic ore type is obviously enriched with sulfide minerals, and has high contents of Be, Sb, Bi, Th, U, and T1. Three oreforming stages are recognized, i. e., the magmatic crystallization-differentiation stage, forming stratoid, disseminated and massive orebodies or ores; the magmatic injection stage, forming injected massive orebodies or ores; and the magmatic hydrothermal stage, forming pegmatitic ores. Diagenetic temperature, pressure and oxygen fugacity of ore-bearing gabbros are 1296- 1009℃, 296 MPa, and 10^-5.62 - 10^-7.43 Pa respectively, and ore-forming temperature and sulfur fugacity of sulfides are 571 -449℃ and 10^-19.35 ℃ 10^- 19.77Pa respectively. The Weiya deposit is a magmatic deposit related to alkali ultramafic-mafic complex. The ore-forming process is predominantly magmatic crystallization-differentiation and injection, with partial magmatic hydrothermal activity occurring at the late stage. Hence, this deposit is tion-magmatic hydrothermal deposit. a polygenetic magmatic differentiation-magmatic injection-magmatic hydrothermal deposit.
出处
《矿床地质》
CAS
CSCD
北大核心
2005年第4期349-360,共12页
Mineral Deposits
基金
国家重点基础研究项目(编号:2001CB409806)资助
关键词
地质学
碱性辉长岩
钒钛磁铁矿
岩浆分异-贯入
岩浆热液
尾亚
新疆
geology, alkali gabbro, V-Ti-magnetite deposit, magrnatic differentiation, magmatic injection,magmatic hydrothermal fluid, Weiya
