Permian plume beneath Tarim from receiver functions

Abstract

Receiver functions for the central Tien Shan and northern Tarim in central Asia reveal a pronounced depression on the 410 km discontinuity beneath the Permian basalts in Tarim. The depression may be caused by elevated temperature. The striking spatial correlation between the anomaly of the MTZ and the Permian basalts suggests that both may be effects of the same plume. This relation can be reconciled with the possible motion of Tarim on the order of 1000 km by assuming that the mantle layer, which has moved coherently with the plate since the Permian, extends to a depth of 410 km or more. Alternatively, the lithosphere and underlying mantle are decoupled at a depth of ∼ 200 km, but a cumulative effect of the Tarim plate motion since the Permian is less by an order of magnitude. A similar explanation is applicable to the Siberian traps.