Thermochemical Structure and Melting Distribution of the Upper Mantle Beneath Intraplate Volcanic Areas in Eastern South China Block

Zhang，Anqi1; Guo，Zhen2,3; Dai，Hongkun4; Yang，Yingjie1,5

2023-12-01

10.1029/2023JB027320

Journal of Geophysical Research: Solid Earth   影响因子和分区

2169-9313

2169-9356

The Eastern South China Block (SCB) has experienced complex Mesozoic-Cenozoic tectonism and intraplate volcanism. However, due to a lack of exhaustive exploration of the upper mantle's thermochemical structure, it is difficult to determine the extent of the lithospheric modification and the mechanisms by which the volcanism generate. Here, we jointly invert Rayleigh wave dispersion, surface heat flow, geoid height, and elevation data to provide a comprehensive thermal and compositional structure of the upper mantle beneath eastern SCB and infer regions of partial melting. Our model reveals widespread lithospheric thinning in the eastern SCB and large variations of lithospheric composition with a more fertile eastern Lower Yangtze lithosphere than the lithosphere elsewhere, suggesting the lithosphere of the eastern Lower Yangtze is more severely modified than the rest of the SCB. Moreover, two high-temperature anomalies are revealed: one beneath the eastern Lower Yangtze and the other beneath the Pearl River Delta region, associated with the Pacific plate subduction and Hainan plume, respectively. The high-degree partial melting (∼6%) in the asthenosphere beneath the Lower Yangtze is responsible for the strong ongoing lithospheric modification and the young intraplate volcanism in the Nvshan and Subei areas. Small-scale upper mantle convections triggered by the large mantle upwellings created a low value of ∼3% melts, possibly responsible for the intraplate volcanism in the coastal CB and less severe lithospheric modification. We demonstrate that the lithospheric thickness and its thermochemical state are the key factors that influence the composition and evolution of intraplate volcanism in the eastern SCB.

eastern South China block intraplate volcanism joint inversion melt distribution thermochemical structure

SCI

英语

第一 ; 通讯

GEOSCIENCES

2-s2.0-85179932134

Scopus

1.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,China
2.Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen,China
3.Shanghai Sheshan National Geophysical Observatory and Research Station,Shanghai,China
4.State Key Laboratory of Geological Processes and Mineral Resources,School of Earth Sciences,China University of Geosciences,Wuhan,China
5.Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology,Southern University of Science and Technology,Shenzhen,China

Zhang，Anqi,Guo，Zhen,Dai，Hongkun,et al. Thermochemical Structure and Melting Distribution of the Upper Mantle Beneath Intraplate Volcanic Areas in Eastern South China Block[J]. Journal of Geophysical Research: Solid Earth,2023,128(12).

Zhang，Anqi,Guo，Zhen,Dai，Hongkun,&Yang，Yingjie.(2023).Thermochemical Structure and Melting Distribution of the Upper Mantle Beneath Intraplate Volcanic Areas in Eastern South China Block.Journal of Geophysical Research: Solid Earth,128(12).

Zhang，Anqi,et al."Thermochemical Structure and Melting Distribution of the Upper Mantle Beneath Intraplate Volcanic Areas in Eastern South China Block".Journal of Geophysical Research: Solid Earth 128.12(2023).