地质论评2026，Vol.72Issue(2)：413-440,28.DOI:10.16509/j.georeview.2025.09.025
新疆北部可可托海地区阿拉尔复式花岗岩体形成机制的探讨
Discussion on formation mechanism of Aral complex granitic plutons in Koktokay area,northern Xinjiang
摘要
Abstract
The Aral composite granitic pluton in the Koktokay area of northern Xinjiang is composed of different intrusive units.This study obtained LA-ICP-MS zircon U-Pb isotopic ages of 217.3±3.8 Ma,218.6±2.4 Ma,and 216.5±6.3 Ma for the medium-to fine-grained biotite monzogranite,medium-grained porphyritic two-mica syenogranite,and medium-to coarse-grained porphyritic two-mica syenogranite,respectively.The rocks are characterized by high silicon,low titanium,enrichment in potassium and aluminum,and depletion in magnesium;strong negative Eu anomalies(δEu=0.30～0.72);enrichment in large-ion lithophile elements(LILEs)such as Rb,Th,and U,and rare earth elements(REEs)such as La,Ce,Nd,and Sm,while being depleted in Ba,Nb,Sr,P,and Ti.They belong to typical low-Ba and low-Sr granites,indicating that the pluton was likely the product of low-degree partial melting of crustal sources.The n(176Hf)/n(177Hf)ratios of the medium-grained porphyritic two-mica syenogranite and the medium-to coarse-grained porphyritic two-mica syenogranite are 0.282642～0.282800 and 0.282675～0.282763,respectively.Their εHf(t)values range from-0.02 to 5.73 and from 1.03 to 4.37,respectively,and their second-stage Hf model ages(TDM2)are 759～1052 Ma and 827～993 Ma,respectively.This suggests that the magmas were likely derived from the partial melting of Precambrian microcontinental block crustal materials,with the involvement of mantle-derived components.Integrating regional data,it is proposed that during the Triassic period,a large mid-to deep-crustal magma chamber might have existed in the Altay Orogenic Belt.This magmatic activity involved the supply of mantle-derived magmas and underwent complex magmatic evolution processes,including assimilation of crustal materials and magma mixing.The heat source for this activity was likely related to the Siberian super mantle plume.关键词
阿拉尔复式岩体/可可托海/阿尔泰/中亚造山带/三叠纪/壳源岩浆/岩浆混合/新疆北部Key words
Aral complex granitic plutons/Koktokay/Altay/Central Asian Orogenic Belt/Triassic/Crustal magma/magma mixing/northern Xinjiang引用本文复制引用
蔺新望,王星,张亚峰,赵端昌,赵江林..新疆北部可可托海地区阿拉尔复式花岗岩体形成机制的探讨[J].地质论评,2026,72(2):413-440,28.基金项目
本文为新疆阿尔泰成矿带喀纳斯和东准地区地质矿产调查项目(编号:DD20160006)、新疆地质勘查基金项目(编号:A16-1-LQ01)、陕西省公益性地质调查项目(编码:202402、202510)及国土空间规划(2020-2035)项目(2020-SKD-50)的成果. This paper was supported by the Project of Geological and Mineral Survey in the Kanas and Eastern Junggar Regions,Altay Metallogenic Belt(No.DD20160006) （编号:DD20160006）
the Xinjiang Geological Exploration Fund Center Project(No.A16-1-LQ01) （No.A16-1-LQ01）
the Shaanxi Provincial Public Welfare Geological Survey Project(Nos.202402,202510) （Nos.202402,202510）
and the National Territorial Space Planning(2020-2035)Project(No.2020-SKD-50).The authors extend their sincere appreciation to Prof.ZHAO Tongyang and Prof.ZHANG Yuxu for their valuable suggestions （2020-2035）
