Paleomagnetic studies of Jurassic and Cretaceous rocks in the Eastern Qiangtang Terrane, Tibetan Plateau, China

Abstract

This thesis presents research on the paleogeographic data of Early Cretaceous granites and Mid-Late Jurassic limestones in the Zaduo area, Eastern Qiangtang Terrane, Tibetan Plateau, China. The granite study provides further insight into the Lhasa-Qiangtang collision, while the limestones have been remagnetized due to the India-Eurasia collision. The magnetic fabric of the remagnetized limestones documented the NNE-SSW oriented compression during the remagnetization. A comparative study of the remagnetized and unremagnetized rocks, which mainly concentrates on their rock magnetic properties, was also carried out. The combination of gravity and paleomagnetic data reveals a coupled lithosphere-scale oroclinal deformation of the eastern ending of the Qiangtang Terrane. The thesis consists of five chapters. Chapter 1 investigates an Early Cretaceous granite in the Zaduo area and presents a new paleomagnetic investigation on the granite. Chapter 2 discusses the remagnetization of the Jurassic limestones in the Zaduo area and its implications for the India-Eurasia collision. Chapter 3 is about the lithosphere-scale oroclinal deformation of the eastern ending of the Qiangtang Terrane. Chapter 4 focuses on the remagnetization of the limestones and the NNE-SSW oriented compression during the India-Eurasia collision, and Chapter 5 is about the comparative study of the remagnetized and unremagnetized rocks.