Mixed carbonate-siliciclastic contourite drift deposits associated with the entrance of an Atlantic-Mediterranean corridor (late Miocene, southwest Spain)

Carbonate contourite drifts are poorly documented in the onshore record because of difficulty implementing diagnostic criteria for their recognition. Accordingly, little is known about relative position carbonate with respect to ancient platforms, seaways and shallow passages within context palaeoceanography. This study presents a fossil example mixed carbonate-siliciclastic drift cropping out quarry Osuna (Sevilla province, southern Spain) at northern end Guadalhorce Corridor, Miocene strait connecting Mediterranean Sea Atlantic Ocean Betic Cordillera. Based on facies sedimentary structures, studied succession divided into three units: 1) lower unit, Unit 1, 33-m thick large bodies mega cross-stratification pointing southeast secondarily northwest interpreted as drift; 2) intermediate 2 0.5–2-m terrigenous conglomerate body eroding top 1; 3) uppermost 3 consists 6-m siliciclastic-dominated herringbone dominant direction structures tidal deposits. The large-scale sediment cross-beds, presence reactivation surfaces grain-size changes, unidirectionality were recognition 1 generated by inflow Mediterranean. challenges classical “siphon” model Atlantic-Mediterranean water-mass circulation pattern this age. conglomerates evidence regional uplift margin Guadalquivir Basin that promoted change depositional mode from bottom-current dominated (Unit tide-dominated environment after closure Corridor Messinian.