Neogene history of the Tabernas basin (SE Spain) and its Tortonian submarine fan development

Abstract

The Tabernas Basin is a structural depression in the Alpine nappes of the Betic Cordilleras in southeastern Spain. From the Tortonian to the Plio/Pleistocene, sedimentation in this basin was strongly influenced by tectonic activity. At the onset of the Tortonian, basin subsidence caused submergence of an alluvial fan system and a small submarine fan complex developed in a water depth of at least 600 m. Total basin subsidence was in the order of 1200 m. Initial Tortonian submarine fan growth and evolution of fan systems has been reconstructed and is shown in 6 palinspastic maps. In the early Messinian, sediment accumulation on the fan, and basement rise caused a regressive trend. Reefs along the NW margin of the basin were part of a regional barrier reef system and muddy sediments were deposited in its centre. Prior to the development of an evaporitic phase, uplift and emergence of the eastern half of the basin took place along NW-SE trending faults. During this evaporitic phase, selenitic gymsum formed on the muddy sediments of the still submerged sea floor of the western half of the basin. At the Messinian-Pliocene boundary, folding and emergence of the sea floor coincided with the genesis of an anticlinorium in the south: this is the now emerged Sierra Alhamilla. From Pliocene onward, after a short period of subsidence, uplift prevailed contributing to the development of a southward prograding fan delta in the western part of the basin. The structural and depositional history of the basin seems to agree with its setting within a strike-slip zone. Movement along this zone is associated with the convergence of the African and Iberian lithospheric plates.