Geochemistry, Hf Isotopes and Petrogenesis of Badaogou Monzonotic Granites from Linjiang, Jilin Province
Tian Lidan
Sun Fengyue
Wang Li
Liu Jinlong
Wu Qiong
Abstract：The tectonic setting is complex while Jurassic granite is relatively limited in the Badaogou area,which results in a lack of theoretical basis for its regional tectonic evolution studies.This paper presents a synthesis of geochemical and zircon UPb chronological and Hf isotopic study on the Badaogou monzonitic granites.The zircons of rock samples which have distinct rhythmic growth zoning are long cylindrical and euhedral well-formed,implying the features of magmatic origin.Dating results indicate that the rocks were formed in the Early Jurassic (176± 1 Ma).The rocks which obviously are rich in LREE and have unconspicuous europium anomalies (0.96-1.03) with regard to high SiO2 (68.93％-70.02％),low MgO (1.27％-1.45％),CaO (1.80％-2.78％) as well as A/CNK (0.92-1.02) belong to sub-aluminous and high-K calc-alkaline granites,being of the characteristics of Ⅰ-type granites.The εHf (t) values vary from-20.21 to-24.08,and the two-stage model age (tDM2) ranges from 2 498 to 2 740 Ma.These samples are enriched in LILE and depleted in HFSE (such as Nb,Ta,P,Ti),with Mg# values of 45-47.Analyses show that the rocks came from the melting of neo-Archean lower crust.Combining with the background of regional contemporary magmatic distribution,it is concluded that the formation of monzonotic granites from Badaogou could be related to the subduction of the Paleo-Pacific plate under the Eurasian continent.
Keywords：monzonitic graniteszircon U-Pb datingHf isotopeEarly JurassicBadaogougeochemistrygeochronology
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 436-448 )