FastFind »   Lastname: doi:10.1029/ Year: Advanced Search  

AGU: Tectonics

 
Abstract
Cited By (1)
 

Abstract

Displacements, strains, and rotations within the Afar depression (Djibouti) from restoration in map view

D. Rouby

Géosciences Rennes, Université de Rennes, Rennes, France

Th. Souriot

Géosciences Rennes, Université de Rennes, Rennes, France

J. P. Brun

Géosciences Rennes, Université de Rennes, Rennes, France

P. R. Cobbold

Géosciences Rennes, Université de Rennes, Rennes, France

Within the Afar depression (Djibouti) the stratiform basaltic lava flows (emplaced between 4 Ma and 1 Ma) cover the two thirds of the depression. Because of the desert climate, they are almost non eroded. The topography can then be used as a reference surface to measure the vertical offset of younger faults. Using a detailed map the southeastern part of the depression showing the fault pattern and the vertical offset on each fault (obtained from stereoparts of SPOT images), we have restored the topography in map view. We have computed the fields of finite displacement, rotation and strain. The field of horizontal displacements shows vectors trending to the NE on average. This direction is compatible with the displacement to the NE of the Arabian plate with reference to the African plate. In detail however, displacement vector trend from NNE–SSW to NE–SW. Major axes of strain ellipse trend NE–SW suggesting that major faults (Nl20) are dominantely extensional. Strain intensities and magnitudes of block rotations are increasing from southwest to northeast of the restored area. Magnitudes of block rotations are very small compared with those obtained from paleomagnetic measurements. Therefore we computed a second restoration that covers a smaller area where the true vertical offset of the major faults taking into account the sedimentary fill of basins were avalaible. This second model gives rotation magnitudes in better agreement with paleomagnetic data but still underestimates. We discuss these results with the available kinematic models of the southeastern part of the depression.

Received 7 September 1994; accepted 15 November 1995; .

Citation: Rouby, D., Th. Souriot, J. P. Brun, and P. R. Cobbold (1996), Displacements, strains, and rotations within the Afar depression (Djibouti) from restoration in map view, Tectonics, 15(5), 952–965.

Cited By

Please wait one moment ...