沉积与特提斯地质2025，Vol.45Issue(1)：168-186,19.DOI:10.19826/j.cnki.1009-3850.2024.04008
早中三叠世金沙江缝合带碰撞造山过程岩浆作用响应
Magmatism during collisional orogenic processes in Early-Middle Triassic Jinsha River suture zone
摘要
Abstract
The Jinsha River suture zone is characterized by diverse geological structures and complex magmatic processes.There are considerable controversies about the timing of its initial collision and subsequent extension time limit.This paper uses zircon U-Pb dating and rock geochemical analysis methods to study the monzonite and granite porphyry in the Gonjo area in the mid-north section of the Jinsha River suture zone,analyzing the formation age,rock origin,material source,and tectonic setting of the rock mass.Research shows that Gonjo monzonite belongs to the shoshonite series and is classified as I-type granite,with a diagenetic age of(250±1)Ma.The rock mass is enriched in light rare earth elements,with Mg#values ranging from 28 to 30,Rb/Sr ratios from 0.07 to 0.11,and Nb/La ratios from 0.43 to 0.49,indicating that it is the product of partial melting of basic metavolcanic materials in the lower crust.The diagenetic environment is a tectonic environment in which the crust uplifts and thickens during the end of subduction to the early collision period.Gonjo granite porphyry belongs to the medium-potassium calc-alkaline series of S-type granite,with a crystallization age of(244±2)Ma.The Mg#values of the rock range from 26 to 29,with FeOT/MgO ratios between 4.43 and 4.98,Al2O3/TiO2 ratios of 47.57～51.12,and CaO/Na2O ratios between 0.28 and 0.49,indicating that it is the product of partial melting of the crustal metasandstone.The diagenetic environment is an extensional tectonic environment after collision.Based on the geochronological data,Hf isotope,and geochemical data of the Permian-Middle Triassic granitic rocks within the Jinsha River suture zone,and in combination with previous research results,it is believed that during the process of subduction,collision,and extension of the Jinsha River orogenic belt,more and more crustal materials participated in the magma source region.关键词
金沙江缝合带/初始碰撞/碰撞后伸展/I型花岗岩/S型花岗岩Key words
Jinsha River suture zone/initial collision/post-collision extension/I-type granite/S-type granite分类
天文与地球科学引用本文复制引用
杨礼创,唐渊,祝向平,李勇,吴昊,吴波..早中三叠世金沙江缝合带碰撞造山过程岩浆作用响应[J].沉积与特提斯地质,2025,45(1):168-186,19.基金项目
中国地质调查局项目(DD20240026,DD20221635) （DD20240026,DD20221635）
