Permian continental basins in the Southern Alps (Italy) and peri-mediterranean correlations

Abstract

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First evidence for Permian-Triassic boundary volcanism in the Northern Gemericum: geochemistry and U-Pb zircon geochronology

“…This tectonic event could have been related to the so-called "Mid-Permian Episode" of Deroin & Bonin (2003), connected with the transformation of strike-slip to an extensional tectonic regime. A similar stratigraphic gap and geodynamic changes were described in the Eastern and Southern Alps as well as in the wide peri-Mediterranean realm (Krainer 1993;Cassinis et al 2012 and references therein) that was reflected in the evolution of two major tectono-sedimentary cycles. Cassinis et al (2012) considered this stratigraphic gap to be synchronous with the geomagnetic IR event (Menning 1995(Menning , 2001Steiner 2006) that has been postulated by Isozaki (2009) as the trigger agent for the Pangea breakup.…”

“…The acid to intermediate volcanism, as it has been already mentioned, is dominant in the Cisuralian with the exception of the Ligurian Alps, where this volcanism is situated above the IR horizon (Dallagiovanna et al 2009;Cassinis et al 2012 Vozárová et al 2013), as well as the late Bashkirian-Moscovian uplift of the metamorphic nappes in the NGU Variscan orogenic belt (Vozárová 1973(Vozárová , 1996Vozárová et al 2013 and references therein). It is post-collisional with respect to the Late Devonian-Mississippian collision, that led to the accretion of the NGU orogenic belt to the Prototatricum crust (the term Prototatricum is coined by Broska et al 2013 for the common Variscan basement of the Tatricum and the Veporicum Units) which was the part of the Galatian Superterrane (von Raumer & Stampfli 2008;von Raumer et al 2009;Stampfli et al 2011), with the oceanic crust of the Prototethys.…”

Sedimentary evolution of the continental Early–Middle Triassic Cañizar Formation (Central Spain): Implications for life recovery after the Permian–Triassic crisis

“…The analogies of the Cafiizar Fm. with other coeval units of neigh boring basins of western Tethys perhaps indicate that general uni form paleoecological conditions existed during the Early Triassic over extensive areas (Cassinis et al, 2003;Payne et al, 2004;Galfetti et al, 2007a;Cassinis et al, 2012). It would have included vast surfaces with a general depleted oxygen content, punctuated by elevated CO2 values and general acidic conditions that prevailed after the catastrophic PiT boundary volcanic event in Siberia until middle Spathian, when new, improved paleoenvironmental condi tions allowed life recovery (Twitchett, 1999).…”

First report of a Middle-Upper Permian magmatism in the SE Iberian Ranges: characterisation and comparison with coeval magmatisms in the western Tethys

“…As a consequence, the affinity of the rocks should be better explained as transitional between subalkaline and alkaline. This feature is characteristic of some Middle-Upper Permian magmatisms from the western Tethys (e.g., Pyrenees, Catalonian Coastal Ranges, Corsica-Sardinia and southern France; Lago et al, 2004a;Lapierre et al, 1999;Traversa et al, 2003;Ubide et al, 2010), resulting from a transitional tectono-magmatic regime, between the Variscan compression and the Alpine extension (e.g., Bixel, 1988;Bonin, 1988;Cassinis et al, 2012).…”

“…10) presents high Nb-Ta contents, a marked negative anomaly in K cles in the western Tethys (Bixel, 1988;Bonin, 1988). These cycles reflect the transition from late-Variscan transtension to early Alpine extension and opening of the Neotethys Ocean with progressive westward marine ingression (Cassinis et al, 2012;Lago et al, 2004a). The first cycle ("Orogenic") is composed of calc-alkaline subintrusive acidic to effusive basic-intermediate rocks (Gaggero et al, 2007 and references therein).…”