Geochemical characteristics of lamprophres in the Xikuangshan antimony ore deposits, Hunan province
湖南锡矿山锑矿矿区煌斑岩的地球化学特征

Element and isotope geochemistry of the lamprophyres veins in the Xikuangshan antimony ore deposits issystematically researched in this article, aiming at discussing genesis of lamprophyres. The lamprophyres studied were formed ca 120Ma ago, prior to mineralization chronology, and is considered to be closely related to antimony mineralization in the Xikuangshan area. The MORB-normalized spidergrams of samples studied are rich in high field element, with depleted Nb-Ta and non-depleted Ti, strong enrichment in Th and weak enrichment in Ce, being similar to spidergrams of volcanic arc basalt. Their tectonic setting probably is destructive plate boundaries of an inter continent. The rare-earth element of sample studied have characteristics of high total contents and non-distinct Eu anomalies. The chondrite-normalized REE patterns are right-inclined. The isotopic contents of sample have high 87 Sr/87 Sr and low 143Nd/144 Nd. Combining element and isotope geochemistry with geological history, the lamprophyres studied in the area result from partial melting of enriched REE and HSFE fluid related to subduction of metasomatic mantle, mixing with a little underlying granite and limestone compositions.