江西冷水坑铅锌矿床含矿花岗斑岩石英斑晶中熔体包裹体研究：对矿床成因的约束

通常认为，中低温（<300oC）条件下在NaCl-H2O体系中依然具有较高溶解度的Pb和Zn，很难在岩浆-热液条件下沉淀形成斑岩型矿化。然而，江西冷水坑矿床中的铅锌矿化与花岗斑岩体显示出密切的时空关系，被认为可能是一个斑岩型铅锌矿床。为验证该假说，前期对花岗斑岩开展了详细的岩相学研究，并在其石英斑晶中发现了大量熔体包裹体，这为调查斑岩岩浆是否提供了形成冷水坑矿床所需的Pb-Zn提供了可能。为此，本研究拟以冷水坑铅锌矿床花岗斑岩石英斑晶中的熔体包裹体为主要研究对象，在详细显微测温学基础之上，采用电子探针及激光消融等离子质谱原位分析技术，查明熔体包裹体的成分，特别是其内的Pb-Zn元素含量，进而评价斑岩岩浆对矿床形成的贡献，厘定花岗斑岩与矿床的成因关联。

It is generally believed that at medium and low temperature (<300oC), Pb and Zn in the NaCl-H2O system are still difficult to precipitate and form porphyry mineralization due to the high solubilities. However, the Lengshuikeng deposit in Jiangxi Province is considered to be a porphyry lead-zinc deposit according to the close temporal and spatial relationship between Pb-Zn mineralization and the granite porphyries. To check this hypothesis, detailed petrographic studies on granite porphyries were carried out, and a large number of melt inclusions were found in the quartz phenocrysts, which providing a possibility to investigate whether the porphyry magma provides Pb-Zn in Lengshuikeng deposit. Therefore, we plan to investigate the melt inclusions using in situ analysis techniques (i.e. LA-ICP-MS, EMPA) based on detailed microthermometry, to: (1) clarify the composition of the melt inclusions, especially the contents of Pb and Zn; (2) evaluate the contribution of porphyry magma to the formation of the deposit; (3) determine the genetic relationship between granite porphyries and the Pb-Zn mineralization.