贵州松桃西溪堡锰矿沉积地球化学特征

贵州黔东断裂坳陷带是贵州重要的锰矿成矿带，并发育新元古代大塘坡期的一套完整“黑色岩系”，锰矿主要赋存于该黑色岩系中。本文以松桃西溪堡锰矿床为例，通过岩石学、矿物学、地球化学等研究方法，探讨这类锰矿床的成矿物质来源及成因。研究表明矿石中的矿物组分复杂，结构构造类型多样，富集As、Sb、Ag、Co、Mo、W、Cs和Ba等元素，Fe／Ti、（Fe＋Mn）／Ti、A1／（AI＋Fe＋Mn）、Y／Ho、Nb／Ta比值，以及Cr．zr和Th．u图解均揭示成矿过程中有热水物质参与；V／（V＋Ni）、V／Cr比值表明锰矿形成于缺氧环境；稀土元素分布模式、Ce、Eu异常及La．Ce、La／Yb．EREE图解显示锰矿形成于被动大陆边缘环境，并具有热水沉积特征。因此，古被动大陆边缘是锰矿富集的理想场所，热水（液）活动为其提供了丰富的物质来源。这为锰矿的找矿拓展了新的思路。

Sedimentary geochemical characteristics of manganese deposits in Xixibao,Songtao County,Guizhou Province

Eastern Guizhou sag zone is an important manganese mineralization belt in China, where a complete set of Neoproterozoic Datangpo ＂black rock series＂ has been developed. Xixibao manganese deposit is studied in terms of petrology, mineralogy, geochemistry and other methods in this study to explore the mineral sources of the manganese deposit that hosted in ＂black rock series＂. Studies show that： the complicate mineral composition, the diverse types of ore structures, based on the study on trace elements, in addition to enrichments in As, Sb, Ag, Co, Mo, W, Cs, Ba, the ratios of Fe/Ti, （Fe＋Mn）/Ti, A1/（AI＋Fe＋Mn）, Y/Ho, Nb/Ta and the diagrams of Cr-Zr, Th-U, all show that hydrotherm contribute the process of the sedimentation. The V/（V＋Ni） and V/Cr indicate an anoxic sedimentary environment for these rocks. In addition, the REE distribution patterns, Ce and Eu anomalies, La-Ce and La/Yb-EREE diagrams all suggest that the manganese deposit may have been formed in a passive continental margin with hydrothermal sedimentary affection. All the evidence above show that the manganese deposit has been formed in an ancient passive continental margin rift environment, it is the hydrothermal activities that provided the deposit with massive source material. This research may provide a new idea for the exploration of manganese deposits in Songtao County.