贵州银厂坡银矿床蚀变过程中组分迁移特征

CHARACTERISTICS OF COMPONENT MIGRATION IN THE PROCESS OF SILVER ENRICHMENT IN YINCHANGPO SILVER DEPOSIT,GUIZHOU,CHINA

银厂坡银矿床碳酸盐化蚀变作用与银的矿化富集在空间上紧密相伴，这种蚀变作用导致矿石与围岩中组分有明显差异。本文通过定量计算阐明组分之间的迁移方向；计算表明在银的原生富集过程中，常量组分的带入与带出最不明显；而微量组分Ag和Cu、Pb、Zn、As、Sb、Cd、Ga、Ge带入围岩明显。在银的次生富集过程表现为Ag和Cu、Pb、Cd、Ga、Ge、REE、Al-2O-3、Fe-2O-3、FeO、MnO、K-2O、P-2O-5的强烈带入，以Al-2O-3、Fe-2O-3、K-2O、P-2O-5带入强度最大，这是由于CaO、MgO被淋滤，体积亏损造成强烈带入的假象，而As、Sb、Zn、V、Cr、Co、Ni、CaO、MgO为自围岩中带出组分，以CaO、MgO带出强度最大。REE除原生富集的弱蚀变白云岩→矿化白云岩表现为带出外，其余原生富集过程均表现为带入围岩。造成组分发生迁移的主要因素除各组分自身的地球化学性质的差异外，水岩反应的物化条件也是造成银的不同富集阶段中不同组分发生不同程度迁移的一个重要因素。

The Yinchangpo silver deposit experienced strong carbonatizati on, which has close relationship with the enrichment of silver. In this paper, w e determined TiO-2 as the most immobile component. Calculation of mass balance shows that in the process of original enrichment of silver, the migration of ma jor components is not very strong. However, Cu, Pb, Ga, Zn, Ge, As, Sb, Ag and C d were brought into the host rocks distinctly; in the process of hypo-enrichm ent of silver, Ag, Cu, Pb, Zn, Ga, Ge, Al-2O-3, Fe-2O-3, FeO, MnO, K-2O and P-2O-5, especially Al-2O-3, Fe-2O-3, K-2O and P-2O-5 were brought into the host rocks obviously, but As, Sb, Zn, V, Cr, Co, Ni, CaO, MgO, especially C aO, MgO, were exported from the host rocks. In the whole process of enrichment o f silver, the REEs were imported into the wall rocks excepted the stage of alte ration of dolomite to mineralization of dolomite. Research also shows that the physical and chemical condition of fluid /rock response is an important factor a ffecting the degree of migration of various components in different stages duri ng the process of silver enrichment. The mineralizing components are dominant ly derived from a kind of fluid enriched in Ag, Cu, Pb, Zn, As, Sb, Cd, Ga, Ge, etc. Strongly positive anomalies of these elements and carbonatization are cruci al clues to silver exploration.