Multistage Magmatic Evolution and Cretaceous Peak Metallogenic Epochs of Mufushan Composite Granite Mass: Constrains from Geochronological Evidence
Li Peng
Li Jiankang
Pei Rongfu
Leng Shuangliang
Zhang Xu
Zhou Fangchun
Li Shengmiao
Abstract：The differentiation process of granitic magma is an important factor constraining the metallogenic mechanism of rare metal.The superimposition of multistage magmatic activities in orogenic process could easily lead to the accumulation of metallogenic pegmatite melts.Mufushan composite granite mass,which is composed of multistage granite intrusions,formed an important rare metal ore concentration area in South China.In this paper we report muscovite 40Ar/39 Ar dating results from tantalite-bearing muscovite albite pegmatite of Duanfengshan on the margin of granite mass,and beryl-bearing muscovite albite pegmatite of Daxing in its central region.The 40 Ar/39 Ar ages of muscovite are 127.7 ± 0.9 Ma and 130.5 ± 0.9 Ma.Based on the detailed field work and existing regional isotope chronological data,it is suggested that this area experienced long-lasting multistage magmatic evolution from early to middle Yanshanian.Rare metal mineralization of pegmatite occurred at the end of magmatic activities in Cretaceous,which showed the process of gradual enrichment and mineralization of rare metal led by regional multistage magmatic differentiation and evolution.These geological phenomena showed that Mufushan area has undergone a widely distributed continental collision orogeny in Indosinian and its tectonic setting shifted from continental collision to extensional thinning at Yanshanian.The multistage magmatic activities associated with regional lower crustal melting,which caused by underplating of basaltic magma during the process of lithospheric extension,led to the final rare metal mineralization.
Keywords：40 Ar/39 Ar datingrare metalmagmatic activityCretaceous peak metallogenic epochgranitegeochronology
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 1684-1696 )