Mantle roots of the Emeishan plume: an evaluation based on teleseismic P-wave tomography

Abstract

Abstract. The voluminous magmatism associated with large igneous provinces (LIPs) is commonly correlated to upwelling plumes from the core-mantle boundary (CMB). Here we analyse seismic tomographic data from the Emeishan LIP in southwestern China. Our results reveal vestiges of delaminated crustal and/or lithospheric mantle, with an upwelling in the upper mantle beneath the Emeishan LIP rather than a plume rooted in the CMB. We suggest that the magmatism and the Emeishan LIP formation might be connected with the melting of delaminated lower crustal and/or lithospheric components which resulted in plume-like upwelling from the upper mantle or from the mantle transition zone.

Heat Flow and Rheological Decompaction of the Crust and Upper Mantle in Rift and Plume Structures on the Eastern Margin of Asia

“…7. Плотностная контрастность (а, б, г), интенсивность теплового потока (в) (Jiang et al, 2018) и коэффициент корреляции Q и µ z в разных глубинных срезах µ z (x, y, Hc)-модели тектоносферы (д) в зоне влияния Эмейшаньского плюма: 1-2 -изолинии плотностной контрастности (1), 10 -2 кг/м 2 /км, и теплового потока (2), мВт/м 2 ; 3 -контуры внутренней и промежуточной зон Эмейшаньского плюма (He, Santosh, 2017;Jiang et al, 2018); 4 -разломы: AС -Аджань-Сяоджинь (Agjiang-Xiaojinhe), КР -Красной реки (He, Santosh, 2017); 5 -зоны растяжения; 6 -контур площади корреляционного анализа. Fig.…”

“…7. Density contrast (а, б, г), heat flow (в) (Jiang et al, 2018) and correlation coefficient of Q and µ z for different depth sections of µ z (x, y, Hc)-model (д) in the zone under influence of the Emeishan plume (д) 1-2 -density contrast isolines, 10 -2 кg/m 2 /km (1), and heat f low, mW/м 2 (2); 3 -contours of the inner and intermediate zones of the Emeishan plume (He, Santosh, 2017;Jiang al., 2018); 4 -faults: AC -Agjiang-Xiaojinhe, Red River (He, Santosh, 2017); 5 -extension zones; 6 -contour of the correlation analysis area.…”