CAJ | 학술논문

提近年来湘西黔东地区铅锌矿产勘查成果显著，已发现矿床（点）200余处，铅锌矿主要产于寒武系-奥陶系碳酸盐岩地层中。通过对该地区典型铅锌矿床碳酸盐围岩和成矿期方解石的C、O同位素组成分析，结果表明：碳酸盐围岩的δ13CPDB值（-1.16‰~1.70‰，均值0.51‰）和δ18OSMOW值（18.56‰~22.42‰，均值21.04‰）变化范围较小，组成相对均一，在δ13CPDB-δ18OSMOW图上投影点位于海相碳酸盐岩区；而成矿期方解石的δ13CPDB值（-5.80‰~0.42‰，均值-1.18‰）比围岩略低，δ18OSMOW值（12.96‰~23.05‰，均值18.36‰）有明显的下降，在δ13CPDB-δ18OSMOW图上投影点主要位于上地幔区和海相碳酸盐岩之间。根据C、O同位素组成特征并结合前人研究成果，认为成矿流体中的C主要来源于碳酸盐围岩，S来源于地层中的膏盐层，Pb、Zn主要来源于下寒武统牛蹄塘组地层，成矿流体是一种高盐度的低温热卤水，它与碳酸盐围岩的水-岩反应和降温的耦合作用是该地区成矿期方解石和矿石矿物沉淀的主要机制。
제근년래상서검동지구연자광산감사성과현저，이발현광상（점）200여처，연자광주요산우한무계-오도계탄산염암지층중。통과대해지구전형연자광상탄산염위암화성광기방해석적C、O동위소조성분석，결과표명：탄산염위암적δ13CPDB치（-1.16‰~1.70‰，균치0.51‰）화δ18OSMOW치（18.56‰~22.42‰，균치21.04‰）변화범위교소，조성상대균일，재δ13CPDB-δ18OSMOW도상투영점위우해상탄산염암구；이성광기방해석적δ13CPDB치（-5.80‰~0.42‰，균치-1.18‰）비위암략저，δ18OSMOW치（12.96‰~23.05‰，균치18.36‰）유명현적하강，재δ13CPDB-δ18OSMOW도상투영점주요위우상지만구화해상탄산염암지간。근거C、O동위소조성특정병결합전인연구성과，인위성광류체중적C주요래원우탄산염위암，S래원우지층중적고염층，Pb、Zn주요래원우하한무통우제당조지층，성광류체시일충고염도적저온열서수，타여탄산염위암적수-암반응화강온적우합작용시해지구성광기방해석화광석광물침정적주요궤제。
Great progress has been made in recent years in prospecting for Pb-Zn ore deposits in western Hunan and eastern Guizhou provinces. There are more than two hundred Pb-Zn ore deposits hosted in the Cambrian and Ordovician strata. The authors carried out a systematic analysis of the carbon and oxygen isotopic compositions of carbonate wall rocks and hydrothermal calcites formed at the ore-forming stage. The results show that carbonate wall rocks have relatively homogeneous δ 13CPDB values (ranging from-1.16‰ to 1.70‰, 0.51‰ on average) and δ 18OSMOW values (ranging from 18.56‰ to 22.42‰, 21.04‰ on average); in contrast, hydrothermal calcite has lower δ 13CPDB value (ranging from-5.80‰ to 0.42‰,-1.18‰ on average), and significantly declined δ 18OSMOW values (ranging from 12.96‰ to 23.05‰, 18.36‰ on average). In the δ 13CPDB vs δ 18OSMOW diagram, the wall rocks are plotted in the marine carbonate rock area, and hydrothermal calcites are between marine carbonate rock and upper mantle. In combination with previous results, it is concluded that C of the ore-forming fluids was mainly derived from carbonate wall rocks, sulfur from sulfates in the sedimentary strata, and Pb and Zn from the rocks of lower Cambrian Niutitang Formation. The ore-forming fluids were higher salinity and lower temperature basin brines. Precipitation of ore minerals and hydrothermal calcites probably resulted from extensive fluid-rock interaction between ore-forming fluids and carbonate wall rocks in combination with corresponding decreasing temperature.