关键词: 基性杂岩, 大西沟铁磷矿, 矿床地质特征, 地球化学

Abstract:

The Daxigou huge iron-phosphorite deposit, with low-grade，is located at basic-ultra basic complexes in the southern Kuruktag faulted uplift of the north margin of Tarim platform. Based on the geological feature, geochemical compositions, trace elements, rare earth elements (REES) of ore-bearing anorthosite mass as well as characters of the Daxigou deposit, the iron-phosphorite mineralization has been discussed. It is suggested that ore-bearing lithofacies belong to the alkaline series, major and trace elements in complex are not inconsistent with each other. Such incompatible elements as Ba, Sr, Zr and P are obviously enriched, but the compatible elements Cr, Co and Ni are depleted. Contents of REE are relatively higher, and LREE highly enriched. There is no obvious Eu abnormality. The magma of complex rocks was originated from deep crust. In the late period of magmatism, large amounts of magnetite and apatite crystallized and formed ore body in some local section. By analysing the present exploitation situation of low grade endogenetic iron-phosphorite deposit in North China, it can be concluded that the Daxigou iron-phosphorite deposit will have a good comprehensive utilization perspective.

Key words: basic complex rocks, Daxigou iron-phosphorite deposit, geological characteristics of deposit, geochemistry