Turbidite Systems in North Maghrebin Gliding Nappes

Francois Laval

These Cretaceous formations, tectonically displaced and split up during the Miocene, present a great variety of turbidite facies associations and sequential arrangements along and across the entire orogeny.

In the northeastern Grande Kabylie (Algeria), for example, sedimentary analysis shows (1) muddy and unstable slope facies, channeled sandstone bodies, interchannel deposits, and channel-lobe transition and depositional lobes accumulated in northern subbasins, starting in Neocomian time; (2) lobe and fan fringe or basin plain turbidites and restricted hemipelagic facies in more southern or laterally located subbasins that began deposition later; and (3) small-scale channeled sandstone beds, interchannel and overbank deposits (especially facies E from Mutti), and thin-bedded lobes (minor depocenters transferred to the south during the Albian, while nondeposition surfaces or condensed intervals are observed in the northern subbasins).

In the northern part of the Alpine orogeny of Algeria and Morocco, the characteristics of these turbidite sediments indicate a complex evolution around the Europe-Africa transform fault during the Cretaceous, corresponding with block faulting, uplifts, and transcurrent movements, and emphasized by sporadic resedimented carbonate lithostratigraphic horizons.

The present methods of turbidite study may provide support for reliable paleogeographic reconstruction of internal zones of the Alpine Maghrebin orogeny that had been lacking until now.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.