Palaeoenvironmental reconstruction and early Permian ichnoassemblage from the NE Iberian Peninsula (Pyrenean Basin)

Abstract

Recent finds of tetrapod ichnites in the red-bed and volcaniclastic succession of the Iberian Pyrenean Basin permits an assessment of the faunal diversity and palaeoenvironment of a late early Permian setting. The tetrapod ichnoassemblage is inferred with the aid of photogrammetry and constituted by Batrachichnus salamandroides, Limnopus isp., cf. Amphisauropus (these three ichnotaxa present associated swimming traces, assigned to Characichnos), cf. Ichniotherium, Dromopus isp., cf. Varanopus, Hyloidichnus isp. and Dimetropus leisnerianus. These ichnotaxa suggest the presence of temnospondyls, seymouriamorphs, diadectomorphs, araeoscelids, captorhinids and synapsid pelycosaurs as potential trackmakers. These faunas correlate to the late early Permian. Two ichnoassociations correspond to two different palaeoenvironments that were permanently or occasionally aquatic (meandering fluvial systems and unconfined runoff surfaces, respectively). Ichnotaxa in the fluvial system is more diverse and abundant than in the runoff surfaces system. The Iberian Pyrenean ichnoassemblage reveals the faunistic connection and similarities among nearing basins (Spain, southern France and Morocco) differing from the Central European basins (i.e. German Tambach Formation). Based on the palaeogeography and the climate models of the early Permian, we suggest the correlation of ichnofaunal composition with different palaeoclimate biomes. This results in a diffuse boundary of Gondwana–Laurasia land masses, indicating no geographic barriers but a possible climate control on the faunal distribution. Further studies, integrating data from distant tracksites, should refine these biome boundaries.

Aridification across the Carboniferous–Permian transition in central equatorial Pangea: The Catalan Pyrenean succession (NE Iberian Peninsula)

“…Our results are further compared with those from nearby and equivalent localities (Nagtegaal, 1969;Besly and Collinson, 1991;Gretter et al, 2015;Mujal et al, 2016a). Our sedimentological interpretations follow the reference works by Miall (1985Miall ( , 1992 and Gretter et al (2015).…”

“…On the one hand, the grey to green beds have been attributed to the late Carboniferous-earliest Permian (Stephanian C-"Autunian") based on plant fossil content (Broutin and Gisbert, 1985;Talens and Wagner, 1995;Wagner and Álvarez-Vázquez, 2010; here reviewed through the study of a newly reported plant fossil-site). On the other hand, the red beds have been attributed to the middle-late early Permian (Artinskian) by means of tetrapod ichnotaxa (Mujal et al, 2016a).…”

“…These deposits correspond to point bars of fluvial meandering systems (Mujal et al, 2016a). Interestingly, sandstone layers preserve fine laminations, indicative of low bioturbation (Simon et al, 2016).…”

“…Tetrapod footprints from Les Esglésies (from the Lower Red Unit) were analyzed by Voigt and Haubold (2015) and Mujal et al (2016a). Here we provide additional remarks as well as new footprint-bearing levels identified through the measured section.…”

“…In these cases, raindrops, mud-cracks, surficial arthropod trackways and cylindrical (both vertical and horizontal) burrows are common. Mujal et al (2016a) defined these intervals as unconfined runoff surfaces; similarly, Martí (1996) suggested that explosive eruptions prompted rainfalls that would generate water runoff flows.…”