PRELIMINARY TAPHONOMIC STUDIES OF TERRESTRIAL VERTEBRATE REMAINS AT ARROYO PILMATUÉ, MULICHINCO FORMATION, LAS LAJAS, NEUQUÉN BASIN*

PINO, DIEGO; CORIA, RODOLFO A.; DIAZ MARTINEZ, IGNACIO; TUNIK, MAISA; BELLARDINI, FLAVIO; BAIANO, MATTIA A.; WINDHOLZ, GUILLERMO

San Luis

Encuentro; Reunión de Comunicaciones de la Asociación Paleontológica Argentina (RCAPA 2017); 2017

Universidad Nacional San Luis, APA

A new association of continental vertebrate remains found in the lower section of the Mulichinco Formation (Valanginian),10 km north of Las Lajas, are focus of taphonomic studies. The facies associations correspond to the deposit of fluvialchannel, with lateral migration bars and scarce development of floodplains. The fossils are found in a tabular medium-tocoarse-grained sandstone bed of 1.5-2 m thick, with thin interbedded of conglomerate and well-sorted, very coarse-grainedsandstones (facies a). The remains are semi-articulated, disarticulated, and associated or non-associated. The long bonesare principally NE-SW oriented, with post-mortem modifications such as low to moderate abrasion. Surface modificationsuggests weathering stage 1 to 2, and fragile deformation is recognized in 60% of the specimens. According to these taphonomicfeatures, the larger specimens are considered to be parautochthonous, although with no significant carcass transportation.Dispersions of remains would be due to intermittent energy pulses, which are inferred from gradation of verycoarse-grained sandstones to well-selected conglomerates. Small skeletal elements were easily transported, so they are notassociated with semi-articulated elements of the main carcass.