Geochronology,Geochemistry,Zircon Hf Isotopic Characteristics and Tectonic Setting of Hudugeshaorong Pluton in Balinyouqi,Inner Mongolia
Li Pengchuan
Liu Zhenghong
Li Shichao
Xu Zhongyuan
Li Gang
Guan Qingbin
Abstract：The tectonic setting of Da Hinggan Mountains area at the Late Mesozoic has always been controversial,this paper presents zircon U-Pb age,geochemistry and Hf isotopic data of Hudugeshaorong pluton in order to discuss its formation time and tectonic background.Hudugeshaorong pluton is mainly composed of porphyritic biotite monzogranite with LA-ICP-MS zir-con U-Pb age of 129.9±1.4 Ma (MSWD=0.91),indicating it was intruded at the Early Cretaceous.This granite pluton is high in SiO2 ,Na2 O,K2 O and low in CaO,MgO,enriched in Rb,K,Th,U and Zr,and depleted in Ba,Sr,P and Ti.Rare earth elements show light REE enrichment (LREE/HREE=6.90-9.39)with obvious negative Eu anomalies (δEu=0.35-0.44),the ratio of 10 000×[w(Ga)/w(Al)]is between 2.08 and 3.05,showing that it is typical A-type granite.Hf isotopic analysis results show a positiveεHf(t)values (2.24-9.41),two-stage model ages ranging from 1 030 Ma to 570 Ma,with an average age of 809 Ma.Combining with Th/U and Nb/Ta,we suggest that the primary magma was derived from the partial melting of the Neoproterozoic crust.Hudugeshaorong granite indicates that the study area was in an extensional environment during the Early Cretaceous,we suggest it is more likely related to the closure of the Mongol-Okhotsk Ocean.
Keywords：A-type graniteEarly CretaceousDa Hinggan MountainsgeochronologyHf isotopeextensional environmentgeochemistry
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：13( 1995-2007 )