|
|
岩石学报 2012
Re-Os dating of molybdenites from the Xingjiashan molybdenum-tungsten deposit in Jiaodong Peninsula, China and its geological significance
|
Abstract:
The Xingjiashan molybdenum-tungsten deposit, located in the intersection between North China block and Yangtze block, is a large-scale skarn-type deposit in the North Fushan ore field. It belongs to the regional multi-metal metallogenetic series related to the Early Yanshanian granitoid magmatic actions. In this study, in order to restrict the timing of mineralization, direct Re-Os isotopic dating on molybdenites collected from the skarn ore in the Xingjiashan molybdenum-tungsten deposit have been carried out. The results of Re-Os isotopic dating show that the Re-Os model ages range from 156.91±1.78Ma to 160.70±1.66Ma, with an average of 158.91±1.91Ma, and give an isochron age of 158.70±2.06Ma. Combined with the zircon SHRIMP U-Pb age of 158.53±0.79Ma of the Early Yanshanian granite, it is suggested that the mineralization of the regional molybdenum-tungsten is temporally and genetically related to the granite in the area, and the large-scale re-melting granitoid magma might provided the major metallogenetic materials and hydrotherm. Based on the results of Re-Os isotopic dating presented in this study and available isotopic data published in previous studies, we suggest that the mineralization in the Jiaodong Peninsula since Mesozoic could be divided into four mainly phases: the first is the copper-molybdenum multi-metal mineralization phase at ca. 165~155Ma; the second is the gold mineralization phase at ca. 137~110Ma; the third is the copper-molybdenum-lead-zinc multiple metal mineralization phase at ca. 120~110Ma; and the fourth is the gold-silver-lead-zinc multi-metal mineralization phase at ca. 100~75Ma. They are respectively responding to the multiphase granitoid magmatic actions during Early-Late Yanshanian.
