矿物——成矿与找矿

单颗粒矿物微量元素激光原位定量分析测试数据的大量积累和研究,使矿物成为矿床地球化学研究和矿床勘查的重要示踪剂。本文重点选择磁铁矿、磷灰石、石榴子石、榍石、锆石、绿泥石和绿帘石等的原位分析研究所获得的认识,介绍单颗粒矿物成分组合及变化在矿床类型划分、成矿年龄测定、氧逸度、成矿过程与物质来源、找矿与勘探等方面的应用。不同矿床类型中普遍存在的矿物,如磁铁矿、磷灰石等的微量元素含量及组合差异,提供了矿床类型识别的标志。单颗粒矿物,特别是矿石矿物和密切共生矿物如锡石、铌钽铁矿、赤铁矿、石榴子石、方解石等的原位定年,使成矿年龄的直接准确测定成为现实。矿物中变价元素,如Fe、V、Mn、Ce、Eu含量和/或比值的变化,指示了成矿过程氧逸度及其变化特点。从矿物核部向震荡环带与边部的微量元素含量或同位素组成的变化,示踪了成矿过程中流体来源或性质的变化。斑岩和矽卡岩矿床中与成矿作用关系密切的蚀变矿物,如绿泥石、绿帘石的形成温度、特征微量元素比值,如Ti/Sr、Ti/Co、V/Ni、Mg/Sr等,与距矿床中心距离呈线性函数关系,可定量预测距矿床中心的距离,使以绿泥石、绿帘石为代表的找矿指示矿物研究迅速发展。

Minerals and relevant metallogeny and exploration

Advances in rapid seccesful developments of laser in situ quantitative analysis techniques making mineral to be an importaint indicator for the study of mineral deposit geochemistry and it''s exploration. Collecting the achivments of trace element geochemistry study of magnetite, apatite, garnet, titanite, zircon, chlorite and epidote etc., the discrimination of ore deposits classification, mineralization dating, reconstruction of mineralization oxygen fugasity, mineralization processes and ore-forming sources, and mineral exploration are introduced. Classification of different ore deposits can be discriminated in terms of the trace element contents and their association of widespread common accessory minerals. The in-situ LA-ICP-MS and SIMS dating of single particular of ore or paragenesis minerals, sach as cassiterite, columbite-tantalite, hematite, hydrothermal zircon, apatite, garnet and calcite etc. have provided high precision mineralization ages. The concentrations and/or of redox sensitive elements with multivalence such as Fe, V, Mn, Ce and Eu in accessory minerals can offer great potential in obtaining reliable proxy and estimates of redox conditions for mineralization processes. Systematic variations of trace element and isotopic ratio from the core to the rim of garnet oscillatory zonation are used to fingerprinting of the change or souce of ore-forming fluids. The typical trace element ratios of hydrothermal alteration minerals (epidote and chlorite) such as Ti/Sr, Ti/Co, V/Ni, Mg/Sr have shown a linear function of radial distance from the porphyry Cu deposit center. Accordingly these minerals can be an indicator and important tool for assessment and exploration of porphyry and skarn deposits.