Premium
Sharp Lateral Moho Variations Across the SE Tibetan Margin and Their Implications for Plateau Growth
Author(s) -
Xu Mijian,
Huang Zhouchuan,
Wang Liangshu,
Xu Mingjie,
Zhang Yueqiao,
Mi Ning,
Yu Dayong,
Yuan Xiaohui
Publication year - 2020
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2019jb018117
Subject(s) - geology , plateau (mathematics) , tectonics , seismology , margin (machine learning) , craton , gravity anomaly , receiver function , paleontology , lithosphere , oil field , mathematical analysis , mathematics , machine learning , computer science
The tectonic uplift of the Tibetan Plateau is a focus in the geosciences. Middle‐lower crustal flow is a popular model to interpret the geodynamic mechanism on the margin of the Tibetan Plateau. The model predicts different surface and Moho topographies across the plateau boundary due to the different strengths of the surrounding blocks, that is, sharp boundaries on the eastern plateau boundary and gentle variations in the southeastern plateau boundary. Here, we employ receiver function and common conversion point stacking analysis with the seismic waveforms recorded by the dense ChinArray and other local seismic stations to accurately define the Moho topography in southeastern (SE) Tibet. We find that the Moho under the Tibetan Plateau is much deeper than that under the surrounding Yangtze Craton and Indochina block; abrupt Moho changes are found across the southeastern plateau margin, similar to that under the eastern plateau margin. We interpret these sharp Moho variations across the plateau margin to have developed when the Tibetan Plateau was extruded southeastward in the late Miocene. Subsequent gravity collapse resulted in crustal extension and gentle topographic variation, while the sharp Moho slope was preserved.