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The Use of GOCE Data for Detection and Classification of Mantle Plumes

Dr. Gabriele Marquart(1)

(1) SRON & Utrecht University, Postbox 80021, 3508 TA Utrecht, Netherlands

Abstract

Confined hot upwelling of material in the Earth's mantle is known as a mantle plume. Plumes are believed to origin from th e core-mantle thermal boundary layer and rise through the entire mantle driven by positive buoyancy forces. The gravity signal caused by such a mantle plume is given by the superposition of the effect of the hot anomaly itself a nd the effects of the upward deflected surface and internal phase boundaries. The strength and spectrum of the gravity sig nal depends on the position of the plume in the Earth's mantle, as well as on its temperature, size, and rise velocity, a nd on the mantle viscosity. With the use of numerical fluid dynamic modeling the gravity fields of different mantle plum es are studied and compared to the expected resolution of GOCE. The maximum gravity signal is on the order of 100 mgal and is found when the top of the plume reaches the base of the lit hosphere. The gravity anomaly spectrum of a mantle plume, while rising through the mantle is significantly different from the gravity spectrum of an old plume, which is spreading below the lithosphere. While the gravity field of deep mantle plu mes is mainly characterized by long wavelength signals, plumes encountering the lithosphere base and in an old stage of sp reading exhibit considerable energy in a shorter wavelength band related to the size of the plume head in the first case a nd to the thickness to the asthenosphere in the second case. The possibility to use GOCE data to classify known plumes an d to detect plumes rising through the mantle is discussed.

 

Workshop presentation

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Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry

GOCE04