Geochronology,Geochemistry and Hf Isotopes of Gerizhuotuo Complex Intrusion in West of Anyemaqen Suture Zone
Liu Jinlong
Sun Fengyue
Li liang
Zhao Feifei
Wang Yingde
Wang Shuo
Zhang Yuting
Abstract：The Gerizhuotuo complex intrusion,a typical ‘stitching pluton’with its long axis cutting regional structural lines,is significant in tectonic geochronology for providing an upper-age for the timing of plate collision.The zircon U-Pb dating results indicate that the pluton was formed in 227-224 Ma.Geochemically,porphyritic granite falls into the high-K calc-alkaline se-ries,with high Sr(479-573μg/g)and low Yb(1.03-1.20μg/g)and Mg#(48.7-51.8),being of the characteristics of ada-kitic rocks.The in situ zirconεHf (t)value varies from -2.40 to 2.98,which suggests that the primary magma was derived from partial melting of lower crustal materials.Diorite also shows high-K calc-alkaline affinitie,with a Ti/Yb ratio ranging from 1 930 to 2 178,Nb/Ta ratio ranging from 15.9 to 17.4.It is suggested that a mixture,between basaltic magma derived from partial melting of metasomatized mantle and acidic magma derived from crustal material,produced the dioritic magma.It is concluded that the pluton was formed in a post-collisional tensional environment.
Keywords：zircon U-Pb agezircon Hf isotopeadakiteic rockgeochemistrygeochronology
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：17( 965-981 )