岩石矿物学杂志2026，Vol.45Issue(1)：71-85,15.DOI:10.20086/j.cnki.yskw.2026.4142
拉萨地块北部孔马地区早白垩世花岗闪长岩地球化学、锆石U-Pb年代学及其构造意义
Geochemistry and zircon U-Pb chronology of the Early Cretaceous granodiorite in Kongma area,northern Lhasa Terrane,and their tectonic significance
摘要
Abstract
Cretaceous magmatic rocks are widely distributed in the northern the Lhasa Terrane,and the recorded magmatic-metamorphic events are of great significance for studying the petrogenesis and tectonic setting of Creta-ceous magmatic rocks in the Lhasa Terrane.This paper reports the petrology,geochemical results and zircon U-Pb age of the Early Cretaceous granodiorite exposed in the Kongma area located in the northern Lhasa Terrane.The re-sults show that the LA-ICP-MS zircon U-Pb age of granodiorite in the study area is 113.2±1.3 Ma,which belong to the late Early Cretaceous magmatism.These rocks are belong to the high potassium calc-alkaline series,with alu-minum saturation index(A/CNK=1.05～1.12)and medium negative Eu anomaly,relatively enriched large ion lithophile elements Rb,Th,U,K,and deficient high field strength elements Ti,P,Ta,which is a peraluminous S-type granite.Geochemical characteristics of the rocks shows that they were originated from the partial melting of the ancient crust with the mixing of mantle materials.Combined with the regional data,it is believed that the gran-odiorite in the Kongma area was formed in the tectonic environment of the southward subduction collision of the Bangonghu-Nujiang oceanic crust in the late Early Cretaceous,which may be related to the asthenosphere material upsurge caused by the slab break-off under gravity drag.关键词
拉萨地块/早白垩世/花岗闪长岩/地球化学Key words
Lhasa Terrane/Early Cretaceous/granodiorite/geochemistry分类
天文与地球科学引用本文复制引用
李俊,张士贞,刘函,李奋其,苟正彬..拉萨地块北部孔马地区早白垩世花岗闪长岩地球化学、锆石U-Pb年代学及其构造意义[J].岩石矿物学杂志,2026,45(1):71-85,15.基金项目
中国地质调查局项目(DD20240032) （DD20240032）
国家自然科学基金项目(42002032) Project of China Geological Survey(DD20240032) （42002032）
National Natural Science Foundation of China(42002032) （42002032）
