Geochemistry and U–Pb detrital zircon dating of Paleozoic graywackes in East Junggar, NW China: Insights into subduction-accretion processes in the southern Central Asian Orogenic Belt

Publication year: 2011
Source: Gondwana Research, In Press, Accepted Manuscript, Available online 13 June 2011

Xiaoping, Long , Chao, Yuan , Min, Sun , Inna, Safonova , Wenjiao, Xiao , …

The southern Central Asian Orogenic Belt (CAOB) is characterized by multiple and linear accretionary orogenic collages, including Paleozoic arcs, ophiolites, and accretionay wedges. A complex history of subduction-accretion processes makes it difficult to distinguish the origin of these various terranes and reconstruct the tectonic evolution of the southern CAOB. In order to provide constraints on the accretionary history, we analyzed major and trace element compositions of Paleozoic graywackes from the Huangcaopo Group (HG) and Kubusu Group (KG) in East Junggar. The HG graywackes have relatively low Chemical Index of Alteration (CIA) values (50 to 66), suggesting a source that underwent…

 Research highlights: ► The Paleozoic graywackes in East Junggar were derived from an immature source; ► These rocks were probably deposited in an active tectonic setting; ► Detrital zircon U–Pb dating reveals younger depositional ages for the graywackes; ► The Armantai ophiolite was emplaced prior to the Early Devonian; ► The emplacement of the Kalamaili ophiolite postdates the Early Carboniferous; ► The southern CAOB was formed by a long-lasting southward subduction-accretion process.
image