Mid-depth calcareous contourites in the latest Cretaceous of Caravaca (Subbetic Zone, SE Spain). Origin and palaeohydrological significance

Abstract

Deep marine carbonates of Late Campanian to Early Maastrichtian age that crop out in the Subbetic Zone near Caravaca (SE Spain) contain a thick succession of dm-scale levels of calcareous contourites, alternating with fine-grained pelagitesl hemipelagites. These contourites, characterised by an abundance and variety of traction structures, internal erosive surfaces and inverse and nOlmal grading at various scales, were interpreted as having been deposited under the influence of relatively deep ocean CUlTents. Based on these contourites, a new facies model is proposed.The subsurface currents that generated the contourites of Caravaca were probably related to the broad circumglobal, equatorial current system, the strongest oceanic feature of Cretaceous times. These deposits were formed in the mid-depth (200-600 m), hemipelagic environments at the ancient southern margin of Iberia. This palaeogeographic setting was susceptible to the effects of these currents because of its position close to the narrowest oceanic passage, through which the broad equatorial cun'ent system flowed in the westemmost area of the Tethys Seaway. Regional uplift, related to the onset of convergence between Iberia and Africa, probably favoured the generation of the contourites during the Late Campanian to the Early Maastrichtian.

Correlating Mediterranean shallow water deposits with global Oligocene–Miocene stratigraphy and oceanic events

“…The high amount of planktonic biota in the cross-bedded bioclastic grainstones ( Fig. 5 c) suggests sediment shifting by bottom currents on the outer ramp ( Stow et al, 1996; Martín-Chivelet et al, 2003 ). Bioturbated mudstones with abundant planktonic foraminifers, sponge spicules and radiolarians characterise the distal outer ramp of the Oligocene–Miocene carbonate platforms in the central Apennines ( Brandano et al, 2012; Pomar et al, 2012 ).…”

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

“…The degree of fragmentation and abrasion of the allochems is consistent with the action of strong bottom currents (Martín-Chivelet et al, 2003, 2008Longhitano et al, 2014;Rebesco et al, 2014;Lüdmann et al, 2018;Eberli and Betzler, 2019;Longhitano and Chiarella, 2020). The bioclastic fraction of the facies with abundant bryozoans, echinoids, molluscs, and red algae is a typical Miocene bryomol assemblage (Nelson, 1988).…”

Organic-rich, fine-grained contourites in an epicontinental basin: The Upper Jurassic-Lower Cretaceous Vaca Muerta Formation, Argentina

“…Mud floccule ripples created in flume experiments were produced under suspended sediment concentration of tens of mg/L (Schieber and Southard, 2009). Therefore, bottom-current reworked deposits show rare massive (by en masse deposition) or graded beds (Shanmugam et al, 1993a(Shanmugam et al, , 1993bShanmugam, 2017;Martín-Chivelet et al, 2003;, and common laminated and rippled facies, as found in the described facies associations. Although laminated and rippled facies are also common in turbidites, in our dataset they are not part of the typical Bouma sequence (Tc; Figs.…”

“…For instance, both low-density turbidity flows (sensu Stow and Shanmugam, 1980) and bottom currents (Shanmugam et al, 1993a(Shanmugam et al, , 1993bShanmugam, 2006) record traction transport at the base of the flow. The associated deposits differ by the vertical arrangement of sedimentary structures: turbidites typically record traction structures from a waning flow, whereas bottom current deposits do not (Martín-Chivelet et al, 2003). Hyperpycnal flow deposits share an additional characteristic with bottom currents: inverse-to-normally graded beds due to waxing-to-waning flows that can be confused with the similar bi-gradational energy profile of contourites (Mulder, 2011).…”

“…Event beds display a bioturbated top that is developed during flow pauses (e.g., Stow and Shanmugam, 1980;Ponce et al, 2007;Buatois et al, 2011), whereas beds recording bottom current activity show traction structures with an unbioturbated sharp upper contact (Shanmugam et al, 1993a(Shanmugam et al, , 1993bIto, 2002;Martín-Chivelet et al, 2003;Shanmugam, 2006). Accordingly, the absence of normally graded or bioturbated bed tops suggests a lack of post-event bed, hemipelagic sedimentation.…”