INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
TETRAPOD TRACKS TAPHONOMY IN AEOLIAN FACIES FROM THE PERMIAN OF ARGENTINA
KRAPOVICKAS, V.; BENEDITO, D.; MARSICANO, C.; DE LA FUENTE, M.; MANCUSO, A.; BENAVENTE, C.; OTTONE, G.
SEPM-SOC SEDIMENTARY GEOLOGY
Lugar: Lawrence; Año: 2016 vol. 31 p. 374 - 388
Unexpectedly, ancient eolian environments presents a copious ichnofossil record and particularly widespread by the Permian globally. This singular eolian record with outstanding preservation is rather difficult to explain. We propose to analyze, from a taphonomic perspective, the Permian footprints preserved in aeolian deposits from Argentina with a detailed sedimentological study of the trackway-bearing levels, in order to find evidence that could enhanced evidence their preservation into a stratigraphic genetic eolian framework. Four taphonomic modes are defined based on the preservation quality, and the morphological and extra-morphological features of the footprints. Mode 1 includes with a detail impression of the palm, digits and claws. Mode 2 includes palm and digit impressions associated with bulbouse-shape marginal rims. Mode 3 includes trackways characterized by large bulbous-shape marginal rims and a few palm impressions. Mode 4 includes footprints with shallow digits and palm impression together with sand-crescent marginal rims. The Los Reyunos footprints suggest preservation in dry sand, evidenced by down-slope structure, damp sand evidenced by digits and claw drag marks; changes in slope angle, evidenced by the varying amount of sediment slipping down-slop; difference i the time entombment, suggest by the morphology of rims; and also substrate consistence evidenced by increase in moisture content. The stratigraphic genetic framework for Los Reyunos support changes of the water table and the rise of moisture from the groundwater, plus the rapid entombment o the on the tracking surface due to a high rate of a sediment supply, as the main factor for footprints preservation.