Mixed carbonate-siliciclastic contourite drift deposits associated with the entrance of an Atlantic-Mediterranean corridor (late Miocene, southwest Spain)
Metadatos
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Reolid Pérez, Jesús; Aguirre Rodríguez, Julio; Pérez Asensio, José Noel; Puga Bernabeu, Ángel; Braga Alarcón, Juan Carlos; Martín Martín, José ManuelEditorial
Elsevier
Materia
Bottom currents Palaeoceanography Atlantic-Mediterranean connections Contourite drift Betic corridors
Fecha
2022-08-17Referencia bibliográfica
J. Reolid... [et al.]. Mixed carbonate-siliciclastic contourite drift deposits associated with the entrance of an Atlantic-Mediterranean corridor (late Miocene, southwest Spain), Sedimentary Geology, Volume 439, 2022, 106233, ISSN 0037-0738, [https://doi.org/10.1016/j.sedgeo.2022.106233]
Patrocinador
Juan de la Cierva Project (Ministerio de Ciencia, Innovacion y Universidades) JC2019042375-I project SECAMARA PGC2018099391-B-100; Junta de Andalucia European Commission RNM-190Resumen
Carbonate contourite drifts are poorly documented in the onshore record because of the difficulty of implementing
diagnostic criteria for their recognition. Accordingly, little is known about the relative position of carbonate
drifts with respect to ancient carbonate platforms, seaways and shallow passages within the context of
palaeoceanography. This study presents a fossil example of mixed carbonate-siliciclastic drift cropping out in a
quarry in Osuna (Sevilla province, southern Spain) at the northern end of the Guadalhorce Corridor, a Miocene
strait connecting the Mediterranean Sea and the Atlantic Ocean in the Betic Cordillera. Based on the facies and
sedimentary structures, the studied succession is divided into three units: 1) the lower unit, Unit 1, is a 33-m
thick succession of large carbonate bodieswithmega cross-stratification pointing to the southeast and secondarily
to the northwest interpreted as a contourite drift; 2) the intermediate Unit 2 is a 0.5–2-m thick terrigenous
conglomerate body eroding the top of Unit 1; and 3) the uppermost Unit 3 consists of a 6-m thick siliciclasticdominated
succession with herringbone cross-stratification and a dominant direction of the structures to the
northwest interpreted as tidal deposits. The large-scale sediment bodies with mega cross-beds, the presence of
reactivation surfaces with grain-size changes, and the unidirectionality of the structures were diagnostic for
the recognition of Unit 1 as drift deposits. The dominant sedimentary structures pointing to the southeast in
the drift were generated by Atlantic inflow into the Mediterranean. This challenges the classical “siphon”
model for the Atlantic-Mediterranean water-mass circulation pattern for this age. The conglomerates of Unit 2
evidence regional uplift of the southernmargin of the Guadalquivir Basin that promoted a change in the depositional
mode from a bottom-current dominated (Unit 1) to a tide-dominated environment (Unit 3) after the closure
of the Guadalhorce Corridor in the Messinian.