Sedimentary facies during early stages of flooding in an extensional basin: the Br�che Rouge de Carboneras (Late Miocene, Almer�a/SE Spain)

Abstract

The intramontane basins of the Betic Cordilleras (SE Spain) formed subsequent to the main phase of orogenic deformation during the middle Miocene in a close genetic relation to the Trans-Alboran Shear zone. Left lateral movements along a local branch (Carboneras fault zone, CF; strike NE-SW) of this zone played a major role in controlling the formation and dynamics of the Nijar-Carboneras Basin. To the south of the fault, a major phase of strike-slip faulting is recorded during the late Tortonian. The expression of this event is the Brche Rouge de Carboneras (BRC), which seals a deep denudational surface on top of dislocated fault blocks formed by volcanics of the Cabo de Gata complex and early Tortonian shallow marine calcarenite. The sedimentary facies of this widely distributed unit in the Carboneras-Subbasin mirror the submarine topography and the distribution of the fault zones. Along strike-slip fault zones, autoclastic breccias and neptunian dikes preferentially oriented NW-SE and NE-SW occur, which are interpreted to represent the near-surface expression of the faults. Red limestone forms the groundmass of the autoclastic breccia and infills of neptunian dikes, which exhibit multiple phases of opening of fissures, gravitational sedimentary infill, lithification, and renewed creation of cracks. Steep relief, probably along fault scarps, was mantled by epiclastic volcanic conglomerate with a red carbonate matrix. Well-lithified coarse skeletal limestone rich in planktonic foraminifera formed pavements along sediment starved rocky surfaces in deep water. Laterally, within topographic depressions, the pavement limestone grades into thick accumulations of skeletal rudstone composed of fragmented azooxanthellate corals and stylasterid hydrozoans, which were concentrated by powerful bottom currents and gravitiy flows. Within the shallow water zone of dip slope ramps, cross-bedded calcarenite and calcirudite formed. Based on textures, fabrics and biota, rocks of the BRC were grouped into nine genetic lithofacies which document cryptic, deepaphotic and shallow-photic environments typical of a sediment starved extensional basin.

Heterogeneous extension and the role of transfer faults in the development of the southeastern Betic basins (SE Spain)

“…These considerations suggest that extension in the Gacía depocenter during the Tortonian probably continued along the North Gafarillos fault and was transferred to sinistral displacement along the Carboneras fault to the south (Figure a). Tortonian to Messinian SW and NE directed extension occurred also at the Níjar basin [ Martínez‐Díaz and Hernández‐Enrile , ; Pedrera et al ., ], farther south in the Cabo de Gata region [ Brachert et al ., ; Krautworst and Brachert , ] and offshore at the east Alboran basin [ Comas et al ., ; Booth‐Rea et al ., ; F. Giaconia et al, submitted manuscript, 2014]. Thus, during the Tortonian and the Messinian, the Carboneras fault accommodated differential extension between the Níjar basin and the Cabo de Gata region.…”

Punctuated Neogene tectonics and stratigraphy of the African-Iberian plate-boundary zone: concurrent development of Betic-Rif basins (southern Spain, northern Morocco)

“…These grade abruptly upwards into the deep-marine pelagic marls of the Abad Member, the upper part of the Turre Formation ( Van de Poel, 1994). Their deposition occurred during a major phase of strike-slip faulting that is most strikingly expressed in the Carboneras Subbasin by the volcaniclastic Brèche Rouge de Carboneras (Krautworst & Brachert, 2003). The conformably overlying Abad marl beds of the Nijar Subbasin were laid down in an increasingly restricted, shoaling marine environment ( Van de Poel, 1994).…”

An ichnofabric approach to the depositional interpretation of the intensely burrowed Bateig Limestone, Miocene, SE Spain

“…Cater (1987) evinced how episodic rise of Keuper diapirs was the main control on sedimentation in other contemporaneous basins in the Eastern Prebetic Zone. Meanwhile, Krautworst and Brachert (2001) described one facies (Facies 4) from the Late Miocene Brèche Roue de Carboneras of Almeria (SE Spain) that is constituted by limestones with meniscate back-filled burrows (possible Bichordites). The facies appears to have filled small depressions adjacent to bounding faults.…”