Imprint on the upper mantle discontinuities of a subducted Paleo-Tethys
oceanic lithosphere and the formation of the Emeishan large igneous
province
Abstract
Generally, it is suggested that mantle plume upwelling led to the
formation of the Emeishan large igneous province (ELIP). However, this
notion has been challenged by recent geological and seismic studies. In
this study, 3 profiles of velocity perturbation crossing the ELIP were
drawn following previous tomography, and common conversion point (CCP)
stacking of receiver functions is carried out in the ELIP. The slab-like
high-velocity structure with northeastward subduction is revealed, which
may be associated with an oceanic lithosphere of the Paleo-Tethys
(OLPT). CCP stacking of receiver functions shows that the OLPT generated
an imprint on the 410 and 660 km discontinuities, respectively. Finally,
it is suggested that the OLPT may induce large-scale return flow or
upwelling of the mantle, which contributed to the formation of the ELIP.
Key words: CCP stacking of receiver function; upper mantle
discontinuity; tomography; Oceanic lithosphere of the Paleo-Tethys;
mantle upwelling; Emeishan large igneous province