Sm-Nd isotopic geochronology of the Yinachang Fe-Cu-REE deposit at Wuding, Yunnan Province and its genetic significance
Sm-Nd isotope systematics of ores and fluorites places precise time constraints on REE mineralization of the Yinachang Fe-Cu-REE deposit in Yunnan Province which occur in the Proterozoic Kunyan group. The ore-related fluorites contain high abundant REE, and show a strong enrichment of LREE and a positive Eu anomaly, which is in marked contrast to post-ore fluorites that are HREE enriched. The Sm-Nd isochron ages of the ores and fluorites are 1539±40 Ma and 1617±100 Ma, respectively, and calculated εNd(t) are -4.6 and -3.2. Accurate age determinations of the mineralization demonstrate that the REE mineralization took place during early Mesoproterozoic. Together with other geological evidence from the ore deposit, the primary REE-bearing ore-forming fluids are suggested to have been derived from the Enriched Mantle, and the Yinachang Fe-Cu-REE ore deposit is of volcanic exhalation- hydrothermal sedimentary origin. This study also imply that the sudden large-scale REE mineralization in the Mesoproterozoic epoch may have been induced by alkaline-rich anorogenic magmatism which occurred at marginal rifts of the continent in the Mesoproterozoic.
作 者： 作者单位： 刊 名： 科学通报（英文版） SCI 英文刊名： CHINESE SCIENCE BULLETIN 年，卷(期)： 2005 50(18) 分类号： P5 关键词： Kunyang rift Yinachang Fe-Cu-REE deposit fluorite Sm-Nd isotopic systematics Mesoproterozoic