First dinosaur tracks found in the Mulichinco Formation (Neuquén basin, Argentina): Paleoenvironmental implications

PINO, DIEGO; ZALAZAR, MANUELA; GOMEZ, RICARDO; TUNIK, MAISA A.; CORIA, RODOLFO A.

CRETACEOUS RESEARCH (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2023

0195-6671

This study focuses on the analysis of the first dinosaur tracks discovered in the MulichincoFormation, Neuquén Basin, Argentina. The deposition of this unit occurred during the earlyValanginian, Early Cretaceous, making it the oldest known record of dinosaur tracks in thebasin. The aim of this study is to provide a paleoenvironmental interpretation of the areaand potential trackmakers based on the morphology of the tracks and the facies analysis ofthe depositional system. The depositional system evolved from a moderately sinuousfluvial system in the lower interval to a braid distal plain system with the development ofbodies of water without marine influence, culminating in an estuary with marine influencein the upper interval. The paleoenvironmental conditions during the deposition of the unitwere favourable for the presence and interaction of diversity large continental vertebrates.The track-bearing surfaces in the lower interval suggest that the organisms exploited thetemporary gaps created between channel migration and floodplain formation as areas fortransit or water sources. In the middle interval, the abundant presence of traces fossils of invertebrates and symmetrical ripples suggest a more stable depositional system wherefluctuations in the water column were common. The co-occurrence of various track-makersand remains of large vertebrates described in the Mulichinco Formation is unusual amongtrack sites at the basin. Overall, this study provides new insights into the Early Cretaceouspaleoenvironmental conditions of the Neuquén Basin and the diversity of large vertebratesthat inhabited the region during this time.