bulletin du Service G éologique de l Alg é rie Vol . 5 , n ° 1 , pp. 97 - 107 , 1 fig. , 1994 . Accrétion crustale et tectonique verticale à l Eburn éen dans les massifs des Eglab et du Yetti. ( Dorsale R é guibat , Alg é rie ) . Yamina MAHDJOUB * , Amar DRARENI * et Rachid GANI * * 1 ST , USTHB , BP. 32. El Alia Alger , ( Alg érie ) . * * Universit é de Tizi Ouzou , ( Alg é rie ) . R é sum é : La cro ûte é bum é enne des domaines Yetti - Eglab ( Dorsale r é guibat , Alg érie ) , montre des caract ères typiques de l' Arch é en . L ' essentiel de cette croûte birrimienne s ' est form é autour de 2 , 1 Ga à travers un important volume de mat ériel pr é sentant des caract ères juv é niles : les gneiss gris - granites syn à tardi - lectoniques dat é s à 2,2 - 2 ,1 Ga - et les granites post à anorogé niques - les granites aftouts datés à 2 , 0 Ga . Comme à l ' Arch é en, la tectonique verticale ( raccourcissement homog ène horizontal ) relay é e par une tectonique transcurrente , pr é domine sur l ' accr étion lat é rale . Mots cl é s : Craton Ouest Africain, Dorsale R é guibat , Yetti - Eglab, Alg é rie , Arché en , Ebumé en , accr é tion crustale , gé ochimie, gé ochronologie , d é formation, tectonique verticale , dé formation transcurrente . Eburnean crustal accretion and vertical displacement in Yetti - Eglag massifs . ( Ré guibat Rise , Algeria ) . English abriged version : Previous field studies showed that Lower Precambrian ofYetti - Eglab massifs ( East part of Ré guibat rise , Nord of West Africa craton ) consist of numerous and widespread bodies of granitoids which intruded Birrimian volcanosedimentary sequences weakly or not metamorphosed . Granitoids are emplaced during distinct magmatic episodes : ( 1 ) grey gneissses ( syn to late - orogenic granites ) and ( 2 ) red Aftout granites ( post to anorogenic granites ) . Aftout granites display calc - alkaline to alkaline association ( Kahoui, 1988 ) and 2.08 Ga zircon Pb - Pb age ( Kahoui et al . , submitted ) . Chemical compositions of grey gneisses are those of TTG ( trondhjemites , tonalit é s and granodiorites ) . New Sm - Nd , and Rb - Sr isopopic compositions of these grey gneisses ( granites and associated mafic intrusions ) and their zircon Pb - Pb data show their early proterozoi ' c age ( 2.2 - 2.1 Ga ) and suggest that most of them are generated from a protolith which mantellic origine and whitout significant participation of Archean continental material ( Drareni et Per % submitted ) . As in Guiana shield ( Gruau et al . , 1985) and other West African areas ( Abouchami et al . , 1990 and Boyer et ai , 1992 ) , Ebumean events in Yetti - Eglab are characterised by creation of juvenile crust which seems to occur far influence of Archean domains. However , contrary to other Birrimian area , major magnatic crustal growth seems generated by importante mass of 2.08 Ga post to anorogenic Aftout granites and during final Ebumean history.