Seismic waves convey lithospheric delamination mechanism in South China

lithosphere. They found that there were high-velocity anomalies in the asthenosphere at a depth of less than 90 kilometers.

These high-velocity anomalies could be interpreted as lithosphere blocks that began to delaminate at 180-170Ma, which was later heated by the deep mantle and floated back to its previous position. Large-scale delamination led to lithosphere transformation, triggering thinning of lithosphere and adiabatic upwelling of asthenosphere. Subsequently, lithosphere extended and overlaying crust melted, forming magmatic province in South China.

As further revealed by geochemical analysis, large amounts of water and heat from the convective mantle was required to trigger delamination. As a result, abundant granitoid and mafic rocks were formed, which explained the formation magmatic rocks and metal deposits.

This study proposed a new understanding of the formation mechanism of Mesozoic magma Province in South China, which help to deeply understand the kinetics of the Paleo-Pacific plate and that of the large-scale mineralization during late Mesozoic in South China. It also provides new ideas for the establishment of the deep process of the lithosphere and the connection between shallow magma and mineralization.