RT Journal Article
T1 Spectral analysis of the gravity and elevation along the western Africa–Eurasia plate tectonic limit: Continental versus oceanic lithospheric folding signals
A1 Muñoz Martín, Alfonso
A1 De Vicente Muñoz, Gerardo
A1 Fernández Lozano, Javier
A1 Cloetingh, Sierd
A1 Willingshofer, Ernst
A1 Sokoutis, Dimitrios
A1 Beekman, Fred
AB Large-scale folding is a key mechanism of lithospheric deformation and has been described in many parts ofthe Earth, both for the continental and oceanic lithospheres. Some aspects of this process such as the presence of coupling/decoupling between the crustal deformation and the mantle lithosphere, or between differentlithospheres, make it necessary to accurately control the periodic characteristics of the elevation and of thegravity signal. 1D spectral analysis of gravity and topography profiles is sensitive to a series of factors: thelocation, length and orientation of the profiles, as well as the number of samples taken. We carry out asystematic analysis of the periodicities in the topography and gravity, both 1D and 2D, along the westernborder of the Africa–Eurasia plate tectonic boundary. We analyze the sensitivity of the 1D and 2D spectralanalysis in order to compare the results along a plate boundary where oceanic and continental lithospheresare in contact with different tectonic, kinematic and rheological aspects. Our 1D spectral results indicate that the greater the profile length, the longer the wavelength peaks that are found. Nevertheless there are some periodic signals that appear in almost all the analyzed profiles: 100–250 km for the N–S profiles across oceanic plate boundary and 150–250 km where the plate boundary isdeveloped over continental lithospheres. The 2D spectral analysis avoids the problems found in relation to theparticular location of the profile but the resulting wavelengths are slightly higher than those obtained fromthe 1D spectral analysis. The wavelengths estimated for both oceanic and continental lithospheres at theAfrica–Eurasia boundary (N250 km) show low values of mean mantle strength (b1013 Pa m). he presence of lithospheric folds means that the continental and oceanic lithospheres are mechanically oupled. This had previously been suggested for Iberia but not for the limit between S Iberia and the Terceira riple Junction.The orientation of the lithospheric folds is NW–SE at the contact between continental lithospheres and NNE–SSW at the contact between oceanic lithospheres. This difference is also reflected in the signal anisotropy and must be related to the rotation of the tectonic stresses in the same direction. A large periodic signal (wavelength N600 km) was also detected both in 1D and 2D spectral results. After drawing the filtered values, the resulting maps indicate that this signal is related to the transition between continental and oceanic lithospheres and to the significant changes in crustal and/or lithospheric thickness from the Mid-Atlantic Ridge to the continental margins of western Eurasia.
PB Elsevier
SN 0040-1951
YR 2010
FD 2010-09-22
LK https://hdl.handle.net/20.500.14352/41803
UL https://hdl.handle.net/20.500.14352/41803
LA spa
DS Docta Complutense
RD 17 abr 2025