Compositional and Geochemical Signatures for the Sedimentary Evolution of the Middle Triassic–Lower Jurassic Continental Redbeds from Western-Central Mediterranean Alpine Chains

Abstract

A B S T R A C TCompositional and chemical analyses suggest that Middle Triassic-Lower Liassic continental redbeds (in the internal domains of the Betic, Maghrebian, and Apenninic chains) can be considered a regional lithosome marking the TriassicJurassic rift-valley stage of Tethyan rifting, which led to the Pangaea breakup and subsequent development of a mosaic of plates and microplates. Sandstones are quartzose to quartzolithic and represent a provenance of continental block and recycled orogen, made up mainly of Paleozoic metasedimentary rocks similar to those underlying the redbeds. Mudrocks display K enrichments; intense paleoweathering under a hot, episodically humid climate with a prolonged dry season; and sediment recycling. Redbeds experienced temperatures in the range of 100°-160°C and lithostatic/ tectonic loading of more than 4 km. These redbeds represent an important stratigraphic signature to reconstruct a continental block (Mesomediterranean Microplate) that separated different realms of the western Tethys from MiddleLate Jurassic to Miocene, when it was completely involved in Alpine orogenesis.

The Betic Ophiolites and the Mesozoic Evolution of the Western Tethys

“…This ocean was unrelated to the oceanic systems represented by the Dinarides and Hellenides ophiolites, which developed eastward and concomitant with active subduction processes. This hypothesis is not based only on ophiolite investigations, but is supported by facies analyses and paleontological studies of coeval sedimentary sequences (Tendero et al [39]; Lemoine et al [43]; Lagabrielle et al [44]; Principi et al [77]; Perez-Lopez and Perez-Valera [94]; Critelli et al [95]; Hanne et al [96]; Martin-Rojas et al [97]; Somma et al [98]; Zaghloul et al [99]). …”

“…This microplate, located to the SE margin of the Iberia-European plate, underwent the effects of the Eo-Alpine Upper Cretaceous Orogeny, by convergence of the Iberia-European and Adria-African plates, with subduction toward the south of the Betic oceanic-floor, followed by Paleocene exhumation of some eclogitized relics on the northern continental margin. This Mesomediterranean microplate was subsequently dismembered into its different continental blocks, collectively known as AlKaPeCa (Alboran, Kabylies, Peloritani, Calabria) [88], from the Oligocene onward due to subduction towards the NW under this terrane of a new oceanic microplate (Guerrera et al [8]; Handy et al [59]; Chalouan and Michard [89]; Lonergan and White [90]; Rosebaum et al [91]; Lustrino et al [92]; Perez-Lopez and Perez Valera [94]; Critelli et al [95]). …”

Relationships between Lithospheric Flexure, Thrust Tectonics and Stratigraphic Sequences in Foreland Setting: the Southern Apennines Foreland Basin System, Italy

“…In other alternative interpretations, the nappes of the Calabrian Arc originated from a microcontinent located between the European and African continents (e.g. Wildi, 1983;Guerrera et al, 1993;Critelli and Le Pera, 1998;Critelli, 1999;Mongelli et al, 2006;Critelli et al, 2008;Perri et al, 2008; or the Calabrian-Arc terranes are the result of the amalgamation of three " crustal microblocks" (e.g. Vai, 1992).…”

“…Channel and Mareschal, 1989;Dewey et al, 1989;Guerrera et al, 1993;Critelli and Le Pera, 1998;Guerrera et al, 2005;Perrone et al, 2006;Critelli et al, 2008). The Adria plate experienced abrupt surficial and lithospheric changes, as changing nature of the pelagic basins, onset of siliciclastic sedimentation, huge volumes of cratonic quartzose sediments, emersion and erosion of carbonate platform domains, and deformation of the inner carbonate platform to form a forebulge (Patacca et al, 1992;Sgrosso, 1998).…”

“…13), Tellian Maghrebides (Grande and Petite Kabilies, Eudough, Algers Massif) (KB, Fig. 13) (Wildi, 1983;Bouillin et al, 1986;Guerrera et al, 1993;2005;Mongelli et al, 2006;Perrone et al, 2006;Critelli et al, 2008;Perri et al, 2008Perri et al, , 2010. , 1997), in the Peloritani sector of the arc, and the upper Oligocene to lower Miocene Paludi Formation (northern sector) and Stilo Capo d'Orlando Formation (southern sector).…”