摘要
本文在大岭口银铅锌矿床矿物共生组合特征讨论的基础上,利用包裹体测温及其成分分析、矿物共生组合的相平衡分析、物理化学计算等方法,求得该矿床从成矿早期到晚期的成矿温度变化为298.5→267.0→217.6→167.3C、成矿压力变化为40915.04→13020.26kPa,pH变化为3.0～5.8→6.1→6.7→5.0～7.3(均为相应温度下的pH值),lgfs_2变化为-9.9→-11.2→<-15,lgfo_2变化为<-44→-45.6～-42.6→>-44.4,lgfco_2为-1.55左右.结合矿床地质实际及有关研究资料,作者认为该矿床为中低温陆相火山-次火山期后热液型矿床,导致矿物形成的主要因素是温度的降低和pH值的增高.
A set of ore-forming conditions of Dalingkou silver-lead-zinc ore deposit are determined by analyzing the composition of fluid inclusions and measuring their homogenization temperatures, studying the phase equilibria of mineral paragenesis and calculating the physichemical parameters based on the typical mineral intergrowth. The temperatures decrease gradually from 298.5℃ in the earliest stage to 267.0℃ and 217℃, then to 167.3℃ in the latest stage; the pressures range from 40915.04KPa to 13020.26 KPa; pH increases from 3.0～3.58 to 6.1～6.7 and finally varies between 5.0～7.3 (corresponding to the ore-forming temperatures); lgf S_2 decreases from -9.9 Via 11.2 to -15; lgf O_2is initially less than -44, then varies from -45.6 to -42.6 and ends with -44.4; lgf CO_2 is about -1.55.A comprehensive study of geological setting and mineral information suggested that Dalingkou silvet-lead-zinc ore deposit is a late terrestrial volcano-subvolcanic middle-low temperature hydrothermal ore deposit. The controling factors lead to the precipitation of ore minerals are decrease of temperature and increase of pH.
出处
《地质找矿论丛》
CAS
CSCD
1993年第3期42-51,共10页
Contributions to Geology and Mineral Resources Research
基金
国家自然科学基金课题
编号49202019
