Geological and Geochemical Characteristics of the Zhulazhaga Gold Deposit in Inner Mongolia, China

作     者：JIANGSihong NIEFengjun 

作者机构：InstituteofMineralResourcesChineseAcademyofGeologicalSciencesBeijing100037 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2005年第79卷第1期

页      面：87-97页

核心收录：

学科分类：081801[工学-矿产普查与勘探] 081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：This research was supported by both the former Ministry of Geology and Mineral Resource(K1.4-4) the State Basic Research Program of China(2002CB412606) 

主　　题：gold deposit fluid inclusion oxygen and hydrogen isotopes ore genesis Zhulazhaga Inner Mongolia 

摘      要：Located in Alxa Zuoqi (Left Banner) of Inner Mongolia, China, the Zhulazhaga gold deposit is the first large- scale gold deposit that was found in the middle-upper Proterozoic strata along the north margin of the North China craton in recent years. It was discovered by the No. 1 Geophysical and Geochemical Exploration Party of Inner Mongolia as a result of prospecting a geochemical anomaly. By now, over 50 tonnes of gold has been defined, with an average Au grade of 4 g/ t. The ore bodies occur in the first lithological unit of the Mesoproterozoic Zhulazhagamaodao Formation (MZF), which is composed mainly of epimetamorphic sandstone and siltstone and partly of volcanic rocks. With high concentration of gold, the first lithological unit of the MZF became the source bed for the late-stage ore formation. Controlled by the interstratal fracture zones, the ore bodies mostly appear along the bedding with occurrence similar to that of the strata. The primitive ore types are predominantly the altered rock type with minor ore belonging to the quartz veins type. There are also some oxidized ore near the surface. The metallic minerals are composed mainly of pyrite, pyrrhotite and arsenopyrite with minor chalcopyrite, galena and limonite. Most gold minerals appear as native gold and electrum. Hydrothermal alterations associated with the ore formation are actinolitization, silicatization, sulfidation and carbonation. A total of 100 two-phase H 2 O-rich and 7 three-phase daughter crystal-bearing inclusions were measured in seven gold- bearing quartz samples from the Zhulazhaga gold deposit. The homogenization temperatures of the two-phase H 2 O-rich inclusions range from 155 to 401°C, with an average temperature of 284°C and bimodal distributions from 240 to 260°C and 300 to 320°C respectively. The salinities of the two-phase H 2 O-rich inclusions vary from 9.22wt% to 24.30wt% NaCl equiv, with a mode between 23 wt% and 24wt% NaCl equiv. Comparatively, the homogenization temperatu