Title: Zircon U-Pb Ages and Isotopic Characteristics of the Granitoids in the Ningwu Basin, China, and their Significance
Abstract:Granitic intrusions in the Ningwu basin,outcropping sporadically,consist mainly of quartz monzonite and granite.Few works have been done on these granitic intrusions.This paper presents a detail study...Granitic intrusions in the Ningwu basin,outcropping sporadically,consist mainly of quartz monzonite and granite.Few works have been done on these granitic intrusions.This paper presents a detail study of some granitic intrusions by means of LA-ICPMS zircon dating,Lu-Hf zircon isotope,and Sr-Nd isotope analyses.The U-Pb zircon ages for five granitic intrutions are 128.0±1.7 Ma for Niujishan pluton,126.4±1.3 Ma for Huoli pluton,129.8±1.6 Ma for Gushan pluton (sampling from drill core in the Gushan iron deposit,),130.1±1.5 Ma for Xiaoshishan pluton,and 128.3±1.8Ma for Niangniangshan pluton.These date indicate that the granitic intrusions emplaced in 126~130Ma,suggesting that they were the products of magmatic activity in early Cretaceous.The ages are similar to those of the Gushan and Niangniangshan Formations volcanic rocks and slightly younger than the mineralization ages of the porphyrite iron deposits in the Ningwu basin.The Nd-Sr isotope results suggest that the granitic intrusions derived from the metasomatic mantle,compositionally closing to the EMI,which has relationship with the subduction of the Pacific Plate.The Lu-Hf isotope results imply that the granitic plutons have genetic and evolutional relationship with the mineralized diorites or porphyry diorites.The granitic plutons in the Ningwu basin formed in an extensional geodynamic setting,and were products of the lithospheric thinning in eastern China.Read More
Publication Year: 2011
Publication Date: 2011-01-01
Language: en
Type: article
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Cited By Count: 7
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