Palaeostrait tectonosedimentary facies during late Cenozoic microplate rifting and dispersal in the western Mediterranean

Abstract

Palaeostraits are common features during extension and fragmentation of active continental margins, when back-arc basins are formed and microplates develop through upper-plate extension. In this contribution, we focus on narrow seaways and straits associated with successive pulses of late Cenozoic rifting along the southwestern Eurasian continental margin and the ensuing formation and dispersal of microplates. The incomplete and largely non-cylindrical Africa-Eurasia continental collision in the Mediterranean region provides snapshots of the various phases of microplate fragmentation and dispersal, punctuated by the presence of narrow seaways/straits. These peculiar physiographic conditions induced current amplification and led to the accumulation of characteristic large-scale, cross-stratified deposits and tidal facies in an otherwise generally microtidal setting. Although not univocally related to rifting, the identification of such distinctive sedimentary facies within deformed orogenic belts may ultimately help in terrane analysis and in the discrimination of individual microplates, which were then amalgamated. Recognition and dating of palaeostrait tectono-sedimentary facies can thus constrain the presence and the onset of extension in the geological record.

Straits and seaways: controls, processes and implications in modern and ancient systems

“…The papers included in the current volume provide an excellent overview of state-of-the-art knowledge of modern (Andreucci et (3) tectonic and climatic controls on the evolution of straits and seaways (Cavazza and Longhitano 2022;Dorsey et al 2022); and (4) their feedback with climate changes, paleogeographical reconstructions and preservation of associated deposits (Bahr et al 2022;Kalifi et al 2022;Palcu and Krijgsman 2022). Dalrymple (2022) provides a comprehensive review of the morphology, physical oceanography and facies of modern straits and seaways.…”

“…The stratigraphy is composed of mixed siliciclastic and carbonate sediments that record tidal facies and support a strait interpretation. Cavazza and Longhitano (2022) show how palaeostrait sedimentary infills can be regarded as 'tectonic facies' to disentangle stages of microplate rifting in the geological record. They base their consideration on a number of palaeostraits developed during the Neogene to Quaternary in the Mediterranean, whose remnants are today preserved in outcrop successions.…”

Grain-size analysis of the Late Pleistocene sediments in the Corinth Rift: insights into strait-influenced hydrodynamics and provenance of an active rift basin

“…Grain-size plays a fundamental role in determining the spatiotemporal scales over which internal dynamics of sedimentary systems operate (Ganti, Lamb, & McElroy, 2014;Watkins et al, 2020). The accumulation of deposits under straits-controlled current amplification (Cavazza and Longhitano, 2022;Rossi et al, 2022) also contains grain-size information that reflects the dynamics of sedimentary systems. (sediment fluxes, grain-size, lithostratigraphy, etc.…”