Geochronological and trace-element characteristics of zircon xenocrysts from Yeba Formation basalts in southern Tibet and implications for tectonic evolution of Lhasa terrane
The Lhasa terrane is of great importance as a constituent of the Tibetan Plateau.However,its origin has been a subject of intense debate among geologists for the lack of comprehensive knowledge regarding its basement characteristics.This limited understanding has resulted in misconceptions about the evolution of the Lhasa terrane and an inaccurate assessment of its potential for geological processes related to mineralization.This study focuses on examining the U-Pb geochronological and trace-element characteristics of zircon xenocrysts found in the Yeba Formation basalts in the southern Lhasa terrane.The trace-element characteristics show that the majority of the zircon xenocrysts exhibit characteristics typically associated with S-type granite zircons,suggesting the presence of a crystalline basement composed of metamorphic sedimentary rocks in the southern Lhasa terrane.The analysis of zircon age distribution reveals three distinct peaks at 210,552,and 1 043 Ma,which respectively correspond to Triassic arc magmatism occurring at the southern margin of the Lhasa terrane,Late Ediacaran Proto-Tethys subduction beneath the northern margin of the Gondwana continent,and a geological connection between the Lhasa terrane and the African continent during the Mesoproterozoic era.This study provides new constraints on the future research about the basement characteristics and tectonic evolution of the Lhasa terrane.
万方数据
维普
