Abstract
To investigate the three-dimensional spatial distribution of subducted oceanic slab segments and their consequential effect on the thermal and hydrous composition of the mantle transition zone (MTZ) beneath the entire Tibetan Plateau, we conducted a comprehensive analysis of approximately 655,000 P-to-s receiver functions (RFs), obtained from 735 broadband seismic stations. These RFs were utilized to delineate the 410 km (d410) and 660 km (d660) seismic discontinuities, which represent the upper and lower boundaries of the MTZ, respectively. The RFs were grouped within circular bins with a radius of 1 degree and stacked to image the discontinuities. The mean apparent depths derived based on the 1-D IASP91 Earth model for the d410 and d660 across the entire study area are 412.2±8.3 km and 668.9±8.5 km respectively, and the MTZ thickness is 256.5±6.9 km. The observed apparent depths underwent subsequent correction utilizing multiple velocity models. Several areas in central Tibet exhibit a normal d410 and an anomalously deep d660, which can be attributed to the combined effect of the negative thermal anomaly and dehydration associated with subducted slab segments that have penetrated at least to the d660 depth. The anomalous thickening of the MTZ beneath the southeastern Tibetan Plateau surrounding the Tengchong volcanic field can be explained by the dehydration of the subducted Indian Slab. Significant thinning of the MTZ associated with the deepening of the d410 beneath the western Tian Shan may indicate active thermal upwelling originating from the MTZ.
Recommended Citation
Z. Miao et al., "Topography of the 410 and 660 Km Discontinuities Beneath the Tibetan Plateau and Adjacent Areas," Earth and Planetary Science Letters, vol. 644, article no. 118947, Elsevier, Oct 2024.
The definitive version is available at https://doi.org/10.1016/j.epsl.2024.118947
Department(s)
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Mantle transition zone; Receiver function analysis; Slab dehydration; Slab subduction; Tengchong volcanic field; Tibetan Plateau
International Standard Serial Number (ISSN)
0012-821X
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 Elsevier, All rights reserved.
Publication Date
15 Oct 2024
