Mineralogy, geochronology and occurrence state of the Duanfengshan Nb-Ta deposit in Mufushan area

Abstract

The two large niobium-tantalum deposits, Duanfengshan in the north margin and Renli in the south margin, were reported in the Mufushan area located in the junction of Hubei, Hunan and Jiangxi provinces.In this paper, we present field geological survey, mineralogical and geochronological investigations on the Duanfengshan Nb-Ta deposit, which are important to reveal the metallogenic characteristic, ore genesis and prospecting direction of the Nb-Ta deposit in the Mufushan area.The Duanfengshan Nb-Ta deposit is a typical granitic pegmatite type Nb-Ta deposit.It is mainly located in the densely distributed pegmatite area within the contact zone between the northern Mufushan composite granite and Lengjiaxi Group.The Nb and Ta elements are commonly enriched in the muscovite-ablite pegmatite, and are mainly hosted in the independent manganocolumbite minerals which commonly associated with albite, muscovite and quartz.Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb dating of columbotantalite from the Nb-Ta pegmatite yielded concordant ages of 136.6-136.2 Ma, which denotes the Nb-Ta mineralization age.The data indicate that the ore forming elements of Nb and Ta are probably enriched from the evolution and differentiation of Mufushan granite magma, while the crystal nucleation and growth of Nb and Ta bearing minerals are influenced and controlled by many factors especially the fluid melt of late stage magma as well as the host country rock of biotite gneiss.

Keywords

• la-icp-ms
• u-pb dating
• duanfengshan nb-ta deposit
• mufushan