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Crustal structure under the central High Atlas Mountains (Morocco) from geological and gravity data |
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| Authors: | P Ayarza F Alvarez-Lobato A Teixell ML Arboleya E Tesn M Julivert M Charroud |
| Institution: | aUniversidad de Salamanca, Departmento de Geología, Area Geodinámica, Pza. de la Merced, s/n., Salamanca 37008, Spain bUniversitat Autònoma de Barcelona, Departament de Geologia, 08193 Bellaterra, Barcelona, Spain cFaculté des Sciences et Techniques Fès-Saiss, Fès, Morocco |
| Abstract: | Seismic wide angle and receiver function results together with geological data have been used as constraints to build a gravity-based crustal model of the central High Atlas of Morocco. Integration of a newly acquired set of gravity values with public data allowed us to undertake 2–2.5D gravity modelling along two profiles that cross the entire mountain chain. Modelling suggests moderate crustal thickening, and a general state of Airy isostatic undercompensation. Localized thickening appears restricted to the vicinity of a north-dipping crustal-scale thrust fault, that offsets the Moho discontinuity and defines a small crustal root which accounts for the minimum Bouguer gravity anomaly values. Gravity modelling indicates that this root has a northeasterly strike, slightly oblique to the ENE general orientation of the High Atlas belt. A consequence of the obliquity between the High Atlas borders and its internal and deep structure is the lack of correlation between Bouguer gravity anomaly values and topography. Active buckling affecting the crust, a highly elevated asthenosphere, or a combination of both are addressed as side mechanisms that help to maintain the high elevations of the Atlas mountains. |
| Keywords: | High Atlas Morocco Bouguer gravity anomaly modelling Crustal root Topography Isostatic compensation |
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