Proto-Tethys Record in Paleo-Tethys Belt of East Kunlun:Evidence from Kuhai Mafic Blocks
Zhang Hang
Wang Zongqi
Ma Changqian
Xiong Fuhao
Jiang Hong'an
Guo Yuheng
Abstract：The j unction of the East Kunlun orogen and the West Qinling orogen is a key area for contrasting the tectonic evolu-tion of the East Kunlun orogen with West Qinling orogen and determining the south margin of"Qinling-Qilian-Kunlun"proto-Tethys ocean.Kuhai mafic rocks,situated in the j unction,were structurally placed into a Late Paleozoic foliated turbidites, indicating typical characteristics of mélange.The LA-ICP-MS zircon U-Pb dating indicates that the gabbros in Xueqiong were crystallized at 610—630 Ma,and the mafic rocks in Yari were crystallized with an age of about 504 Ma.Geochemical and iso-topic studies show that Xueqiong gabbros were derived from subcontinent lithosphere mantle in a rift setting.Yari mafic rocks were derived from enrichment mantle wedge modified by subduction metasomatic fluids in subduction,representing the exist-ence of the ocean.According to regional data analysis,the situation that proto-tethys materials mixed in paleo-tethys mélange belt may demonstrates a subduction-accretion process occurred in the junction of the East Kunlun orogen and the West Qinling orogen.From Late Neoproterozoic to the Early Palaeozoic,A'nyemaqen ocean had similar tectonic evolution with Mianlüe o-cean.The margin of proto-Tethys ocean reached A'nyemaqen and Mianlüe mélange.
Keywords：Kuhai Groupmélangezircon U-Pb chronologygeochemistry
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：20( 1164-1182,1180 )