Sand waves, Echinocardium traces and their bathyal depositional setting (Monte Torre Palaeostrait, Plio‐Pleistocene, southern Italy).

Abstract

Stacked cross‐sets, up to 2.5 m thick, produced by sand wave migration and meniscate trace fossils produced by Echinocardium cordatum, both considered in the literature as typical of shallow‐water marine depositional settings, commonly occur in the bathyal Plio‐Pleistocene deposits of Monte Torre (Calabria, southern Italy). The Plio‐Pleistocene sediments form two coarsening‐upward depositional sequences, separated by an unconformity and by a palaeobathymetric gap of at least 300 m. The lower sequence passes upwards from hemipelagic marls and thin‐bedded turbidites to thick‐bedded sandy turbidites, then to sand wave deposits alternated with sandy turbidites, and finally to base‐of‐slope megabreccias. Facies characteristics and relationships, and the occurrence of deep‐sea faunal associations, indicate deposition in the bathyal zone. The facies of the upper sequence reflect a fan‐delta environment, no deeper than a few tens of metres. The depositional setting of the lower sequence, where the sand wave deposits and meniscate trace fossils occur, appears to have been a tectonically controlled seaway, connecting the Tyrrhenian and Ionian Seas. This seaway became progressively narrower with time, evolving into a strait. The overall coarsening‐upward trend reflects the upward transition from a low to a high‐energy environment, possibly caused by the tectonic narrowing of the seaway. Deposition and erosion from high‐concentration turbidity currents and from tidal bottom currents were important processes. Periods of tectonic activity, producing first the uplift of the seaway margins and culminating with the uplift of the strait sequence itself, are marked by‐scattered rockfall deposits. The strait setting, causing the development of powerful, oxygenated bottom currents, produced optimal conditions in the bathyal zone for the colonization of sandy bottoms by a single infaunal r‐selected species, Echinocardium sp.

The Miocene Saint‐Florent Basin in northern Corsica: stratigraphy, sedimentology, and tectonic implications

“…60 years) interbedded with sandwave deposits and derived from the rugged and tectonically unstable basin margins. The Monte Torre paleostrait of southern Italy – which linked the Tyrrhenian and Ionian seas during Plio‐Pleistocene time (Colella & D'Alessandro, 1988) – provides a well‐documented fossil analogue of the Messina Strait. Sedimentation along the axis of the paleostrait was characterized by gravel or very coarse sandwave deposits composed mostly of carbonate biodetritus.…”

“…The Monte Torre sandwave deposits are interbedded with thick turbidites – the result of intermittent high‐density turbidity currents mobilizing mixed bioclastic–siliciclastic detritus from the tectonically active basin margins. Based on ichnofacies, stratigraphic relationships and sedimentary facies analyses, Colella & D'Alessandro (1988) concluded that deposition in the Monte Torre paleostrait occurred at water depths in excess of 350 m.…”

Birth of a hotspot of intraspecific genetic diversity: notes from the underground

“…2001; Cucci 2004); the Catanzaro palaeoisthmus, which repeatedly separated Central Calabria from the Serre massif until the Late Pleistocene (Ghisetti 1979; Caloi et al. 1989); the Monte Torre basin which was open approximately until the uppermost Early Pleistocene (Colella & D’alessandro 1988; Bonfiglio et al. 2002) and separated the Serre and the Aspromonte massifs; and finally the Crati river valley (i.e.…”

A facies‐based depositional model for ancient and modern, tectonically–confined tidal straits

“…b). These seaways were filled by 80‐ to 200‐m‐thick deepening‐upward successions during dramatic phases of tectonic‐driven marine transgressions (Colella and D'Alessandro, ; Longhitano and Nemec, ; Longhitano et al ., ). Tidal currents were amplified flowing in phase opposition from one basin to the other, like the modern Messina Strait (Figs.…”