Early Cretaceous magmatism of the Southern Qiangtang terrane and its tectonic significance

Abstract

The tectonic evolution of the Bangong-Nujiang Tethys is known as the most important event in the late Mesozoic in the central Qianghai-Tibet Plateau. Magmatism is a probe and window for detecting deep crust, which also records the process of tectonic evolution. The magmatic arc formed at Early Cretaceous in the Southern Qiangtang subterrane, was products of the Mesozoic magmatism during the long-term subduction of the Bangong-Nujiang Tethys oceanic lithosphere and the subsequent Qiangtang-Lhasa terrane collision. This article summarizes zircon U-Pb geochronology, major and trace elements, and Sr-Nd-Pb-Hf isotopic data for the Early Cretaceous magmatic rocks located in the southern Qiangtang subterrane of central Tibet. However, there are three hypotheses about the tectonic background of the Early Cretaceous magmatism of the South Qiangtang subterrane: (1) oceanic ridge subduction; (2) slab roll-back; (3) slab break-off.