沉积与特提斯地质2026，Vol.46Issue(2)：255-270,16.DOI:10.19826/j.cnki.1009-3850.2025.09006
羌塘中部早志留世斜长岩岩石成因及其对古特提斯洋早期俯冲的制约
Petrogenesis of Early Silurian anorthosite in central Qiangtang and its constraints on the early subduction of the Paleo-Tethys Ocean
摘要
Abstract
The subduction timing of the Longmu Co-Shuanghu-Lancang Ocean has not been well constrained due to the lack of critical evidence,restricting our understanding of the evolutionary history of the Paleo-Tethys Ocean.This study focuses on the anorthosites intruded into the early Paleozoic ophiolite in the Taoxinghu area of central Qiangtang,northern Tibet,and conducts zircon U-Pb dating,whole-rock geochemical analysis,and zircon Lu-Hf isotopic analysis.This study reveals that the anorthosites yield a zircon U-Pb age of(435±5)Ma,indicating that their formation age is the Early Silurian.Geochemical characteristics show that the anorthosites possess adakitic rock affinities,being enriched in light rare earth elements(LREEs)and large ion lithophile elements(LILEs),and displaying significant positive Eu anomalies.The anorthosites are rich in sodium and poor in potassium(Na2O/K2O＞2).Lu-Hf isotopic analysis exhibits a distinct mantle-derived signature,suggesting their derivation from the partial melting of subducted oceanic crust with contamination by mantle wedge material.This study suggests that the anorthosites formed in a tectonic setting associated with the subduction of the Paleo-Tethys Ocean during the Early Silurian,providing a new constraint on the timing of the early subduction of the Longmu Co-Shuanghu-Lancang Ocean.关键词
羌塘中部/古特提斯洋/早志留世/斜长岩/岩石成因Key words
central Qiangtang/Paleo-Tethys Ocean/Early Silurian/anorthosite/petrogenesis分类
天文与地球科学引用本文复制引用
徐铭蔚,解超明,段梦龙,陈红灿,白希泰,张家俊,史哲..羌塘中部早志留世斜长岩岩石成因及其对古特提斯洋早期俯冲的制约[J].沉积与特提斯地质,2026,46(2):255-270,16.基金项目
国家自然科学基金项目(41872231) （41872231）
