中国地质2024，Vol.51Issue(3)：978-994,17.DOI:10.12029/gc20200706001
大兴安岭中南段哈力黑坝岩体的年代学、地球化学及其构造拆沉作用
Geochronology and geochemistry of Haliheiba pluton in the central and southern Great Hinggan Range and its tectonic delamination
摘要
Abstract
[Objective]The diagenetic age,petrogenetic types,source properties and geodynamic background of the Early Cretaceous granites of Haliheba pluton in the central and southern part of Great Hinggan Range are discussed based on the regional geological survey.[Methods]The lithography of granite,U-Pb chronology,geochemistry and Hf isotope composition of zircon are studied by means of microscope,XRF and(LA-)ICP-MS.[Results]The Early Cretaceous granites in Haliheiba are composed of fine to medium-grained biotite granite and fine-grained porphyritic biotite granite,and zircon U-Pb ages are(139.1±0.7)Ma and(138.4±1.0)Ma,respectively.The granites are characterized by high SiO2(74.09%-77.19%)and alkali enrichment(7.92%-8.46%),and belong to high-K calc-alkaline series.The A/CNK values range from 0.95 to 1.08,indicating that they are metaluminous to weakly peraluminous rocks.The chrondrite-normalized REE patterns are characterized by enrichment of LREEs with(La/Yb)N values varying from 3.69 to 13.17 and by prominent negative Eu anomalies with δEu values ranging from 0.11 to 0.47.The granites show the enrichment of Rb,U,Th,Nb,Ta,Zr and Hf,and the depletion of Sr,Ba,Ti and P.Zircon Hf isotopic compositions suggest that these granites have high positive εHf(t)values(+5.0-+11.2)and fairly young two-stage Hf model ages(408-731 Ma).[Conclusions]The Haliheiba granites are aluminous A-type granites,which were mainly derived from partial melting of the juvenile crustal materials associated with ancient crustal materials under extensional tectonic setting that was probably controlled by lithospheric delamination and thinning.关键词
锆石U-Pb年代学/早白垩世花岗岩/Hf同位素/哈力黑坝/大兴安岭中南段/地质调查工程Key words
zircon U-Pb chronology/Early Cretaceous granite/Hf isotope/Haliheiba/central and southern Great Hinggan Range/geological survey engineering分类
天文与地球科学引用本文复制引用
魏巍,黄行凯,徐巧,蒋斌斌,刘孜,祝新友,巫锡勇..大兴安岭中南段哈力黑坝岩体的年代学、地球化学及其构造拆沉作用[J].中国地质,2024,51(3):978-994,17.基金项目
中国地质调查局项目(DD20160072)资助. Supported by the project of China Geological Survey(No.DD20160072). （DD20160072）
