摘要
云南会泽超大型铅锌矿床规模大、品位富、伴生有用元素多,预示其成矿环境较为特殊。本文分析该矿床矿石中脉石矿物方解石和赋矿碳酸盐地层的C、O同位素组成,结果表明矿石中脉石矿物方解石的C、O同位素组成相对均一,不同矿体(不同标高)、不同产状以及相同矿体不同产状方解石的C、O同位素组成不具明显差别,其δ13CPDB值和δ18OSMOW值分别为-2.1‰～-3.5‰(均值-2.8‰)和16.7‰～18.6‰(均值17.7‰),在δ13CPDB-δ18OSMOW图上集中于岩浆碳酸岩与海相碳酸盐岩之间的狭小范围内。多方面的证据表明:矿床成矿流体为壳-幔混合流体,其中壳源组分可能主要由矿区(或区域)碳酸盐地层提供,而幔源组分则可能与区域大面积峨眉山玄武岩岩浆活动过程中的去气作用有关。
The Huize superlarge Pb-Zn ore deposit is characterized by its bi g scale, high contents of Pb+Zn and multiple concomitant elements, which shows th at its ore-forming condition is relatively special. This paper analyzes the car bon and oxygen isotopic compositions of calcites occurring as gangue mineral in ores and in carbonate strata that host the ores. The results show that the carbo n and oxygen isotopic compositions of the calcites are relatively homogeneous, a nd the carbon and oxygen isotopic compositions of the calcites that appear in di fferent ore bodies, have different occurrences and the same ore body with varied occurrences are not obviously different from one another. The values of ?13CPD B and ?18OSMOW of calcite range respectively from-2.1‰～-3.5‰(the average value is-2.8‰) and 16.7‰～18.6‰(the average value is 17.7‰). In the ?13CP DB vs ?18OSMOW diagram, the samples are plotted in a small field between carbon atite and marine carbonate. A variety of evidences demonstrate that the ore-for ming fluids are of the crustal-mantle mixing type, with the crustal composition s being mainly originated from the carbonate strata in the orefield, and the man tle compositions being related to the degassing process of the Emeishan basalt m agmatism.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2004年第1期53-59,共7页
Geotectonica et Metallogenia
基金
国家自然科学基金项目(40372048
40172038)
云南省省院省校科技合作项目(2000YK-04)
关键词
C、O同位素地球化学
成矿流体
云南会泽超大型铅锌矿床
carbon and oxygen isotope geochemistry
ore-forming fluids
Huize s uperlarge Pb-Zn deposits, Yunnan Province
