Sharpness of the Midlithospheric Discontinuities and Craton Evolution in North China
Abstract
The lithospheric layering and evolution of Archean cratons can be effectively constrained by seismic properties. We present fine‐scale lithospheric discontinuity images of the North China Craton (NCC) using the seismic daylight imaging (SDI) technique, which is also known as the autocorrelogram method. With the aid of large‐scale surface‐wave velocity models, the characters of autocorrelograms related to lithospheric discontinuities in the NCC are investigated. Spatial variation in discontinuity characteristics is revealed across the craton. In the modified/destroyed eastern NCC, both the midlithospheric discontinuity (MLD) and the lithosphere‐asthenosphere boundary (LAB) are rather sharp (~2 km). Various dynamic processes, including juvenile underplating, asthenospheric upwelling, and corner flow induced by paleo‐Pacific Plate subduction, may contribute to such sharp interfaces. In the stable western NCC, P wave reflections cannot easily reveal the LAB, suggesting a diffuse (thicker than 30 km) lithosphere‐asthenosphere transition (LAT). Multiple MLDs are also found that may have arisen during craton formation and multiple phases of rejuvenation of the cratonic lithosphere as evidenced by the petrological results. The use of higher‐frequency data enables us to distinguish among the lithospheric discontinuity styles and favor multiple origins of the MLDs and LAB in the cratonic lithosphere.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 01, 2020
- Source ID
- 10.1029/2019jb018594
Entities
People
- Huaiyu Yuan
- Liang Zhao
- Li‐yun Fu
- Weijia Sun
Organizations
- Chinese Academy of Sciences
- Institute of Geology and Geophysics
- Macquarie University
- National Natural Science Foundation of China
- University of Chinese Academy of Sciences
- University of Petroleum
- Youth Innovation Promotion Association