INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Tafonomy of lacustrine ecosystems.
MANCUSO, ADRIANA CECILIA
Congreso; VI Congreso Latinoamericano de Paleontología de Vertebrados,; 2011
Lacustrine ecosystems are particularly sensitive to environmental changes and their fine-grained deposits commonly display rapid variations in sedimentary facies, which influence fossil preservation. Thus, lacustrine deposits have particular features that allow us to distinguish them from other continental deposits, as a predominance of fine grain sizes, and dominant tabular geometry with a high degree of lateral continuity of individual beds, among others. Taphonomic processes vary with the environment, and they can result in general patterns of preservation that are characteristic of each depositional setting. Two rift basin lacustrine successions (Cacheuta and Los Rastros Formations) in the Middle Triassic of Argentina were analyzed and compared using the taphonomic attributes of the aquatic vertebrate record to find the pattern that characterizes them The most common bioestratinomic processes observed includes float, or rapid fall, transport, decay, predation, scavenging, and turbulence. The different taphonomic features recorded for remains that were found in different lacustrine sub-environments allow us to define a taphonomic model that characterizes the preservation of aquatic vertebrate into rift lacustrine basins. The aquatic vertebrate assemblage studied allows us to suggest that aquatic vertebrate preserved in delta front, underflow, and turbidity current deposits were allochthonous to the lake and probably inhabiting the delta plains and affluent fluvial system. In contrast, the aquatic vertebrate articulated and isolated remains, preserved in open lake deposits, might represent both autochthonous or allochthonous specimens. It shows the main differences in preservation and development of two different aquatic faunas and their relation with the sub-environment they inhabited.