The Evolution of Triassic Granites Associated with Mineralization within East Kunlun Orogenic Belt:Evidence from the Petrology,Geochemistry and Zircon U-Pb Geochronology of the Mohexiala Pluton
Zhang Wei
Zhou Hanwen
Zhu Yunhai
Mao Wulin
Tong Xin
Ma Zhanqing
Cao Yongliang
Abstract：The East Kunlun orogenic belt is not only an important intrusive magmatic tectonic belt,but also a very important poly-metallic metallogenic belt for national economy.There are a large number of granites associated with mineralization formed in Triassic in this area,but the connection between them and the relationship about the tectogenesis are still not clear.In this paper,detailed petrography,element geochemical and zircon geochronological studies are presented for the Mohexiala granite-porphyry associated with silver poly-metallic ore;we summarize the characteristics of Triassic granites associated with minerali-zation within the East Kunlun orogenic belt,and discuss their evolution.Results show that:(1)the Triassic granites associat-ed with mineralization within East Kunlun orogenic belt have a clear trend from low-K and mid-K calc-alkaline series to high-K calc-alkaline and shoshonite series during 250-200 Ma,their A/NK ratios decreased from 2.0 to 1.0 during 240-200 Ma;(2) the (87 Sr/86 Sr)i ratios between 0.710 to 0.715,εNd (t)=-0.6-0.0,the value ofεHf (t)are concentrated in -5-1 and the peak ranges between -2 to -1,indicating that the East Kunlun Triassic granites associated with mineralization were derived from the sources of ancient crust and mixed by mantle material;(3)the East Kunlun area got into the post-orogenic stage at 240 Ma and a large number of calc-alkaline granites formed,the granites gradually reduced after 220 Ma and some alkaline A-type granites occurred between 204 Ma and 210 Ma which indicates that the orogenic belt transformed from collision-orogeny to the intraplate break-up stage.
Keywords：Triassic granitesgeochemistrypetrologypost-collisionalMohexialaEast Kunlun orogenic belt
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：15( 1334-1348 )