Study of seismic tomography in Panxi paleorift area of southwestern China

Magmatic underplating beneath the Emeishan large igneous province (South China) revealed by the COMGRA-ELIP experiment

“…6b). But essentially the encountered high density is consistent with the previous geochemical results (Xu et al, 2004; and accredited geophysical results (Liu et al, 2001;Xu et al, 2014b;Chen et al, 2015), thus providing clear evidence for crustal underplating associated to the past volcanism in Emeishan. This process could be the cause of the non-tectonic uplift of 1-1.5 km in the inner zone of ELIP, such as has been suggested by Chen et al (2015).…”

Mantle origin of the Emeishan large igneous province (South China) from the analysis of residual gravity anomalies

“…The initial density structure is based on the constraints from geophysical surveys and geological data (e.g. measurements of high seismic velocities in the mantle lithosphere, lower crust and upper crust, and the basalts exposed at the surface) (Liu et al, 2001;. We then adjusted the densities within the cuboids, calculate the resultant gravity anomaly, and iteratively fit the observed residual anomaly.…”

“…These remnants of intruded rock and cooled surrounding rock could account for the present positive residual gravity and density anomaly. The inner zone was affected to a greater degree by the mantle plume than the other zones, as indicated by: (1) sedimentologic evidence for kilometer-scale, pre-volcanic uplift and/or doming, including thinning of marine carbonates, a marine to subaerial transition, a local provenance of clastic sediments, and a marked erosional unconformity, evident like paleo-karstic surfaces on the marine carbonates (He et al, 2003(He et al, , 2006Xu et al, 2004); (2) variations in the flood-basalt geochemistry (Low-Ti basalt, High-Ti basalt and alkaline series rocks) from the center to the edge of the dome-shaped structure (such that picrites are restricted to the core of the dome) that are interpreted as hightemperature melts in the center and lower temperature melts at the edge (Xu et al, 2004); (3) the crustal thickness, which ranges from 43 to 55 km in the inner zone, but is thinner (about 40 km) in the middle and outer zones Liu et al, 2001;; (4) variations in the thickness of volcanic rocks across the domeshaped structure (Xu et al, 2004); (5) the spatial variation in residual gravity and the density anomaly as obtained in this study.…”

Upper mantle seismic velocities and anisotropy in China determined through Pn and Sn tomography

“…These differences have been shown by deep seismic sounding using active sources to image the crustal structure [Li and Mooney, 1998] and by three-dimensional tomographic models of seismic velocity [Liu et al, 2000;Xu et al, 2001;Liu et al, 2001;Zhu et al, 2002;Wang et al, 2003;Sun et al, 2004Liu et al, 2005;.…”