云南华昌山Pb-Zn矿床热液流体演化：方解石REE及C-O同位素证据

云南华昌山Pb-Zn矿床是发育在典型褶皱逆冲带内的密西西比河谷型(MVT)铅锌矿床，矿体多沿断裂及断裂两侧分布。本次工作通过对华昌山矿区内关键平硐的编录，识别出4套不同属性的断裂，其中3套对应发育了三种不同期次的热液流体：无矿流体、含铜银流体、含铅锌流体。三期流体均发育热液矿物方解石，通过对三期方解石的原位稀土元素分析发现，这三期流体均是与岩浆作用无关的热液流体，且三期热液流体存在不同的稀土元素配分模式曲线图、不同的lg(Y/Ho)-lg(La/Ho)分布特征和不同的Yb/Ca(原子比)-Yb/La(原子比)分布特征，说明三期热液流体的来源属性不同或者同源但受不同作用的改造。三期方解石的碳、氧同位素值表明热液流体中的碳来自盆地海相碳酸盐岩的溶解作用，方解石的氧同位素特征表明三期流体均为盆地卤水，且铅锌成矿期的流体中混入大气降水。分析华昌山矿床的构造断裂活动和热液流体特征，本文认为区域逆冲断裂之后的张性断裂是控制华昌山铅锌矿床的控矿断裂。

Hydrothermal fluid evolution in the Huachangshan Pb-Zn deposit in Yunnan: Evidences of calcite REE and C-O isotope analyses

The Huachangshan lead-zinc deposit in Yunnan is a typical MVT lead-zinc deposit formed in the fold-thrust belt, with most of the ore bodies located along and on both sides of the faults. In this study, four sets of faults with different occurrences were identified by cataloguing adits, three of which have developed hydrothermal fluids that include a non-mineralized fluid, a copper-silver fluid, and a lead-zinc fluid. All of them develop hydrothermal calcite during the hydrothermal process. As a result of in-situ rare earth element (REE) analysis, it is concluded that calcites originated from hydrothermal fluids unrelated to magmatism. In addition, calcites display different REE distribution patterns, and different positions on lg(Y/Ho)-lg(La/Ho) and Yb/Ca-Yb/La (atomic ratios) coordinate diagrams. These data indicate that the three fluid sources are different or that they have been modified from cogenetic fluid. The carbon and oxygen isotopic values of the calcites indicate a tendency for dissolution and reprecipitation of marine carbonate rocks within the basin. The oxygen isotopic characteristics of calcites indicate that the three fluids originated from basin brines and lead-zinc fluid mixed with meteoric water. Based on the detailed analysis of the fault activities and hydrothermal fluid characteristics, it is considered that the tensile faults after regional thrust fault are the main ore-controlling faults in the Huachangshan lead-zinc deposit.