Gq. Xie et al., Geochemical characteristics of lamprophyres in the Xikuangshan antimony ore deposits, Hunan province., ACTA PETR S, 17(4), 2001, pp. 629-636
Element and isotope geochemistry of the lamprophyres veins in the Xikuangsh
an antimony ore deposits is systematically researched in this article, aimi
ng at discussing genesis of lamprophyres. The lamprophyres studied were for
med 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 eleme
nt, with depleted Nb-Ta and non-depleted Ti, strong enrichment in Th and we
ak enrichment in Ce, being similar to spidergrams of volcanic arc basalt. T
heir 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-normalize
d REE patterns are right-inclined. The isotopic contents of sample have hig
h Sr-87/Sr-87 and low Nd-143/Nd-144. Combining element and isotope geochemi
stry with geological history, the lamprophyres studied in the area result f
rom partial melting of enriched REE and HSFE fluid related to subduction of
metasomatic mantle, mixing with a little underlying granite and limestone
compositions.