Arcuate Moho Fragments Revealed by Dense Seismic Nodal Array in the World’s Largest Continental Center

Session: Recent Development in Ultra-Dense Seismic Arrays With Nodes and Distributed Acoustic Sensing (DAS)
Type: Oral
Date: 4/30/2020
Time: 02:15 PM
Room: 110 + 140
Description: 

Accretionary orogens formed along the convergent plate margins considered as major sites of juvenile crust production. For example, the Central Asian Orogenic Belt (CAOB) is now celebrated for its accretionary tectonics and massive juvenile crustal production in Phanerozoic. In this study, we deployed a linear dense seismic array on a typical juvenile crust area of the CAOB, and a high-resolution image of the crustal structure was obtained from receiver functions based on teleseismic P-waveforms. The order of magnitude greater station density afforded by our passive source nodal array allows exploration of the crust in unprecedented detail. Ultra-high-resolution image of the crustal structure exhibits the strong segmentation characteristics of moho, which containing two arcuate moho fragments. Those arcuate moho fragments located between the outcrops of the Paleozoic volcanic arcs and exhibit opposite magnetic anomaly characteristics to the volcanic arcs, which we interpret as relict inter-arc basins. This new result suggests that subduction-related inter-arc basins may as an important part of the juvenile crust generation process and causing a much higher rate of crust production, which sheds new light on the continental growth process at the long-studied accretionary orogens.

Presenting Author: Xusong Yang

Authors