Ph.D. Candidate from the College of Resource, Environment and Tourism, CNU Published Research Paper in Top Geophysics Journal Earth and Planetary Science Letters

Recently, Earth and Planetary ScienceLetters, one of the journals included in Nature Index and a top journal forearth science, published online the research paper by postgraduates Zhang Zijian et al. from the College of Resource, Environment and Tourism titled Paleomagnetic constraint on the formation of the Eastern Himalayan Syntaxis: A new late Eocene result from the Mangkang area of the eastern Tibetan Plateau.

The Qinghai-Tibet Plateau is known as the roof of the world, and the Himalayan Mountains in the south of the plateau is the product of the collision between India and Asia in the midEoceneEpoch. Since the late Eocene Epoch, the continuous extrusionof the Indian Plate on the Asian Continent led to the overall rise of the Qinghai-Tibet Plateau and then significant changes in the topography, landform, environment and ecology of the northern and southeastern regions of the Qinghai-Tibet Plateau. The Himalayan Mountains features a rough east-to-west distribution, while the Hengdian Mountains abruptly runs from north to south. This sharp turn of nearly 90° forms the Eastern Himalayan Syntaxis(EHS) consisting of towering mountains such as Namjagbarwa (7,756m) and Gyala Peri (7,281m). This region is also one of the most prone to geological disasters, such as the 8.6-magnitude earthquake in Zayu in 1950. It is of great significance to study how the EHS was formed for the evolution of the geological structure and the history of the active structure in this region as well as the construction of national major projects.

Funded by the Key Research Project of the National Natural Science Foundation of China (91855216), Zhang Zijian et al. carried outtectonic paleomagnetic, rock magnetic, U-Pb chronological andpetrographic studies on the trachytes in Mankang, southeast Tibet in the late Eocene Epoch. Results showed that the Indian Plate and the Burma Block had been wedged into the Asian Continent for about 600km since the late Eocene Epoch (Figure 1). This displacement is consistent with the giant right-lateral strike-slip of the Sagaing Fault Zone in east Myanmar (400-600km), indicating that the Shantai Block in the east of the Sagaing Fault Zone did not have an obvious southward escape. This research provides a key direction for determining how the EHS was formed, connects the tectonic activities of the EHS with the lateral extrusion of the southeastern margin of the Tibetan Plateau, and provides a new perspective on the evolution of the region since the late Eocene Epoch.

Figure 1 Latitude Changes in Asia, India, and Mangkang over 60 Million Years Ago

This paper was funded jointly by projects No. 91855216, 42172254 and 41872221 of the National Natural Science Foundation of China.

(February 22, 2023)