Joint modeling of potential-field data and geodynamic interpretation for northeast Algeria

Abstract

of potential-field data and geodynamic interpretation for northeast Algeria. Journal of African Earth Sciences, Elsevier, 2019, 159, pp.(M. Hamoudi). AbstractThe crustal structure beneath the northeastern continental part of Algeria is still largely unknown. Here we use potential field data processing, modeling and interpretation in order to investigate the deep sedimentary layers of this area and the transition with the basement. Indeed the gravimetric and magnetic field maps unveil the main geological domains of North Algeria: the AlCaPeKa domain, the Tellian Nappes, the Atlas and the South-Atlasic Fault (SAF). Our modeling approach combines the prediction of gravimetric and magnetic field signals along 4 N-S profiles that cross those domains and using constraints from seismic lines. The resulting cross-sections reveal the roots of the main E-W tectonic detachments of this area: the northern Suture Zone, the Tell Front, and the SAF. It seems that they are all initiated in the lower crust, nearby the continental/oceanic crustal transition for the Suture Zone, and several tenths of kilometers south from this transition for the Tell Front and the SAF detachments. Using these detachments, the lower parts of the crust are sometimes uplifted to only 5 km deep in the crust, while the upper crust is sometimes thickened to reach 15 km of thickness. Large magnetization and density contrasts are observed right beneath the Suture Zone.

Rheological and kinematic conditions for forced subduction initiation at continental passive margins

“…The late Cenozoic exhumation episodes identified in the British Isles and adjacent regions were most likely caused by the transmission of compressional stresses into continental NW Europe from the Mid-Atlantic Ridge and the Alpine orogen (Holford et al, 2009;Ziegler et al, 1995). (Benhenni et al, 2019;Hamai et al, 2015;Leprêtre et al, 2013); the Cantabrian margin: (Teixell et al, 2018;Viejo & Gallastegui, 2005a), the Brazilian margin: (Chulick et al, 2013;Milani & Zalán, 1998;Stanton et al, 2019). (d, h, l) Cartoons showing wavelength of deformation as function of mantle lithosphere strength.…”

“…(c, g, k) Crustal models of the passive margins indicating lengthlong wavelength folding as a function of mantle lithosphere strength. The compilations are based on: the Algerian margin:(Benhenni et al, 2019;Hamai et al, 2015;Leprêtre et al, 2013); the Cantabrian margin:(Teixell et al, 2018;Viejo & Gallastegui, 2005a), the Brazilian margin:(Chulick et al, 2013; Milani & Zalán, 1998;Stanton et al, 2019). (d, h, l) Cartoons showing wavelength of deformation as function of mantle lithosphere strength.…”