D.3. GASTRÓPODOS MARINOS DE LA CUENCA JURÁSICA DE CHUBUT: FORMACIONES LEPÁ, MULANGUIÑEU Y OSTA ARENA

FERRARI MARIEL

Relatorio XXI Congreso Geológico Argentino

ASOCIACION GEOLÓGICA ARGENTINA GEOLOGÍA Y RECURSOS NATURALES DE LA PROVINCIA DEL CHUBUT Editor Nicolás Foix, Asociación Geológica Argentina, Buenos Aires

Año: 2022; p. 1 - 1701

The present research aims to provide an updated systematical knowledge of the Early Jurassic marine gastropods from the Chubut province and their paleobiogeographical implicantions. Since more than ten years an exhaustive research on this mollusks has been started for the Pliensbachian-Toarcian interval in Chubut, taking into consideration the outdated systematic knowledge of these faunas in the region at that time; a complete taxonomic studio of the group allowed to supply new evidence of many gastropod species from serval marine localities in the study area. The gastropod faunas recovered so far at the jurassic Chubut basin comprises representatives of four orders of Gastropoda Cuevier, such as Patellogastropoda Lindberg, Vetigastropoda Salvini - Pläwen, Caenogastropoda Cox and Architectibranchia Haszprunar including memebrs of 16 families, 24 genera and 39 species. The most representative groups are the vetigastropodos and caenogastropods; architectibanchids has been recently reported from sierra de Tecka being the firts occurrence of the taxa in the early Pliensbachian of the Chubut province so far. The jurassic Chubut basin dispalys a significant potencial of Pliensbachian - Toarcian marine gastropod species, which have also showed close taxonomic affinities with coeval faunas from the Neuquen basin. This suggests the existence of a shallow marine connection between both basins during the Pliensbachian - Toarcian interval which had allowed a marine biotic exchange of the gastropod faunas between both areas at that time. The present analysis based on jurassic marine gastropods strongly contributed to the systematical knowledge of the group in the Early Jurassic of the Chubut province, and their paleobiogeographical relationships with other coeval gastropod assemblages from Argentina.