Laboratoire Of Geodynamique
Laboratoire Of Geodynamique
Nassim H.,Laboratoire Of Geodynamique |
Laurent D.,Center Detude Et Dexpertise Sur Les Risques |
Rachid B.,Laboratoire Of Geodynamique |
Fahem D.,Laboratoire Of Geomorphologie Et Georisques G&G
Bulletin of Engineering Geology and the Environment | Year: 2017
This article contributes to the analysis of the various factors that interact in triggering and reactivating of landslides in Béjaïa city and its eastern coastal region. These factors are associated with lithologic nature of the various geological formations outcropping, morphology and its evolution during the Quaternary period, rainfall patterns and seismic context; however, other causes exist in this case, anthropogenic factors. The multiplicity of typologies identified types of movement grounds (landslides, mudflows, rock falls, falling, etc.) that reflect the diversity of mechanical behavior of materials encountered, but also the permanent unfavorable conditions and triggering of varying intensity over time encountered at each site. © 2017 Springer-Verlag Berlin Heidelberg
Doukkari S.A.,Laboratoire Of Geodynamique |
Ouzegane K.,Laboratoire Of Geodynamique |
Godard G.,University Paris Diderot |
Diener J.F.A.,University of Cape Town |
And 4 more authors.
Lithos | Year: 2015
Adrar Izzilatène in the Egéré-Aleksod terrane of the LATEA metacraton (Hoggar, Algeria) exposes one of the best preserved examples of eclogite facies metamorphism in Hoggar. Three distinct stages of metamorphic development are recognised, namely, the pre-peak stage (M1), characterised by garnet, amphibole, epidote, quartz and rutile, the peak eclogite facies stage (M2), consisting of omphacite, garnet, edenite, epidote, quartz and rutile, and the retrograde stage (M3), where initial decompression resulted in the appearance of plagioclase, the development of pargasite+plagioclase kelyphites and finally the formation of anhydrous plagioclase+diopside coronas. Porphyroblastic omphacite has a jadeite content of up to XJd=0.36, which is the highest yet observed for eclogite facies rocks from the Tuareg Shield. Garnet growth zoning patterns are characterised by flat profiles in the cores (XAlm=0.55-0.60; XPrp=0.12-0.16; XGrs=0.26-0.30) before showing a decrease in almandine to XAlm=0.45, coupled to an increase in pyrope to XPrp=0.29 and decrease in grossular to XGrs=0.26 at the rims. Calculated P-T-MH2O pseudosections show that the prograde M1 assemblage equilibrated at 13-14kbar and 580°C, before pressure and temperature increased to 19kbar and 650-700°C at fluid-saturated conditions during peak metamorphism. Retrogression involved near-isothermal decompression to 8-9kbar and 700-750°C at fluid-undersaturated conditions. Prograde-to-peak metamorphism of the Izzilatène eclogite could have involved either oceanic or continental subduction, followed by exhumation as the area was obducted towards the LATEA metacraton during the Pan-African orogeny and the assembly of Western Gondwana. © 2014 Elsevier B.V..