Crustal evolution and metallogeny in relation to mantle dynamics: A perspective from P-wave tomography of the South China Block

• Significant high velocity perturbations suggesting remnant subducted slabs
• Prominent upwelling from the mantle transition zone beneath South China
• Distribution of the major mineral deposits located above zones of low velocity perturbation

The South China Block, composed of the Yangtze and Cathaysia sub-blocks which were sutured along the Jiangnan Orogen, preserves the records of multiple tectonothermal and metallogenic events coeval with global supercontinental cycles. In this study, we attempt to evaluate the mantle dynamics in this region based on P-wave tomographic analyses from data recorded by the China seismic network from 2007 to 2014. Our study reveals significant velocity perturbations in the upper mantle and mantle transition zone beneath this region which we correlate with various features including remnant and stagnant slabs resulting from Neoproterozoic subduction events and prominent mantle upwellings. Four vertical cross-sections along the latitudinal profiles indicate significant low velocity perturbation located at the mantle transition zone and upper mantle beneath the Cathaysia block and Jiangnan orogenic belt.South China is one of the major multi-metal provinces of the globe, and carries several large-scale ore deposits associated with a variety of tectonic settings. The distribution of major mineral deposits in the Yangtze and Cathaysia blocks as well as along the Jiangnan Orogen reveals a remarkable correlation between the location of the deposits and deep-seated low velocity P-wave anomalies. These features highlight the role of mantle dynamics and resultant crust mantle-interaction as well as crustal melting and recycling in generating the major metallogenic belts in this region.

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