%0 Journal Article
%A Gómez Ortiz, David
%A Tejero López, Rosa
%A Babín Vich, Rosa Blanca
%A Rivas Ponce, Antonio
%T Crustal density structure in the Spanish Central System derivedfrom gravity data analysis (Central Spain)
%D 2005
%@ 0040-1951
%U https://hdl.handle.net/20.500.14352/50197
%X Shallow and deep sources generate a gravity low in the central Iberian Peninsula. Long-wavelength shallow sourcesare two continental sedimentary basins, the Duero and the Tajo Basins, separated by a narrow mountainous chain calledthe Spanish Central System. To investigate the crustal density structure, a multitaper spectral analysis of gravity data wasapplied. To minimise biases due to misleading shallow and deep anomaly sources of similar wavelength, first anestimation of gravity anomaly due to Cenozoic sedimentary infill was made. Power spectral analysis indicates twocrustal discontinuities at mean depths of 31.1F3.6 and 11.6F0.2 km, respectively. Comparisons with seismic datareveal that the shallow density discontinuity is related to the upper crust lower limit and the deeper source correspondsto the Moho discontinuity. A 3D-depth model for the Moho was obtained by inverse modelling of regional gravityanomalies in the Fourier domain. The Moho depth varies between a mean depth of 31 km and 34 km. Maximum depthis located in a NW–SE trough. Gravity modelling points to lateral density variations in the upper crust. The CentralSystem structure is described as a crustal block uplifted by NE–SW reverse faults. The formation of the system involvesdisplacement along an intracrustal detachment in the middle crust. This detachment would split into several high-anglereverse faults verging both NW and SE. The direction of transport is northwards, the detachment probably being rootedat the Moho.
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