Abstract:

Xiaohalajunshan gabbro, consisting of hornblende gabbro and magnetitebearing gabbro, intruded into Carboniferous volcanicsedimentary rocks in southeast Tekesi city. The hornblende gabrro comprises clinopyroxene, hornblende and plagioclase. The magnetitebearing gabbro mainly comprises plagioclase and magnetite. All these rocks contain magmatic calcite, which is in equilibrium with plagioclase, clinopyroxene and/or biotite. The studied gabbro samples show enrichments of light rare earth elements and depletions of heavy rare earth elements without obvious Eu anomalies. These rocks are also enriched in large ion lithophile elements and depleted in high strength field elements. Petrology and geochemical characteristics suggest that the magma was produced by the partial melting of carbonated mantle in very low degree.

Key words:  gabbro, magnetite, calcite, Xinjiang, Southwest Tianshan