The numerical simulation for lithospheric mantle delamination triggered by oceanic plate subduction

The mechanism of the rapid thinning of lithosphere in old and cold craton has been debated for a long time. Basically, some people concluded two fundamental mechanisms to explain this evolution: one is thermal erosion by underlying asthenosphere and the other is delamination of lithospheric mantle. To reveal the specific evolution of delamination by plate subduction, we used a numerical method in Citcom code to simulate the whole process from the initial subduction to eventual delamination of sub-continental lithospheric mantle (SCLM) which can be detached into upper mantle. We assumed that the weak mid-lower crust and SCLM would be physically delaminated into the upper mantle during the period of oceanic plate subduction. Some values of parameters would be changed to represent different conditions such as the velocity of subduction, the thickness and yield strength of SCLM. From a series of cases, we picked up an optimal result that suggests a plausible evolution of the delamination especially for the lithospheric destruction in north China craton. Above all, we may conclude that subduction plays an important role in the whole process of delamination.