East African topography and volcanism explained by a single,migrating plume  

作　　者：Rakib Hassan Simon E.Williams Michael Gurnis Dietmar Muller 

机构地区：[1]School of Geosciences,Room 412,Madsen Building F09 Eastern Avenue,The University of Sydney,NSW,2006,Australia [2]Seismological Laboratory,California Institute of Technology,Pasadena,CA,91125,USA [3]Now at Geoscience Australia,GPO Box 378,Canberra,ACT,2601,Australia [4]State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China

出　　处：《Geoscience Frontiers》2020年第5期1669-1680,共12页地学前缘（英文版）

基　　金：supported by ARC grants IH130200012 and DP130101946;supported by the National Science Foundation under award EAR-1645775;undertaken with the assistance of resources from the National Computational Infrastructure(NCI),which is supported by the Australian Government。

摘　　要：Anomalous topographic swells and Cenozoic volcanism in east Africa have been associated with mantle plumes.Several models involving one or more fixed plumes beneath the northeastward migrating African plate have been suggested to explain the space-time distribution of magmatism in east Africa.We devise paleogeographically constrained global models of mantle convection and,based on the evolution of flow in the deepest lower mantle,show that the Afar plume migrated southward throughout its lifetime.The models suggest that the mobile Afar plume provides a dynamically consistent explanation for the spatial extent of the southward propagation of the east African rift system(EARS),which is difficult to explain by the northeastward migration of Africa over one or more fixed plumes alone,over the last≈45 Myr.We further show that the age-progression of volcanism associated with the southward propagation of EARS is consistent with the apparent surface hotspot motion that results from southward motion of the modelled Afar plume beneath the northeastward migrating African plate.The models suggest that the Afar plume became weaker as it migrated southwards,consistent with trends observed in the geochemical record.

关 键 词：Numerical mantle flow models Deep mantle flow LLSVP morphology Plume dynamics Plume motion Dynamic topography 

分 类 号：P542[天文地球—构造地质学]