IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Actualistic taphonomy of freshwater mollusks from the argentine Pampas: an overview of recent research progress
Autor/es:
CRISTINI, PAULA ANDREA; DE FRANCESCO, CLAUDIO GERMÁN; HASSAN, G.S.; TIETZE, ELEONOR
Lugar:
Montevideo
Reunión:
Workshop; Workshop Actualistic Taphonomy in South America (TAAS 2017); 2017
Resumen:
Historically, thedevelopment of taphonomic studies in freshwater environments has been scarceand mainly restricted to the Northern Hemisphere, with almost no information onhow taphonomic processes work (and eventually differ) in the SouthernHemisphere. We present here an overview of the main results obtained inactualistic taphonomic studies on freshwater mollusks conducted in the PampaPlain of Argentina, since 2008. Research included patterns of distribution oflive and dead mollusks, live/dead fidelity at local and regional scales and deadand fossil shell preservation. Studies were conducted above and below thesediment-water interface (SWI), including both descriptive and experimentalapproaches. Live/dead fidelity and taphonomic studies were compared betweenstreams and lakes (the two most conspicuous aquatic environments in the area)and among shallow lakes exhibiting differences in water quality and substrate.Additionally, a field experiment of two and a half years of duration was placedin one of these lakes to evaluate shell dissolution below the SWI. Overall, resultsindicated that DAs reflected the richness and evenness of modern communities aswell as shell size, and exhibited variations due to local environmentalconditions (salinity, hardness, productivity). Fidelity in abundance of singlespecies was poor, with dead shells being more abundant in higher saline lakes. Thetaphonomically active zone occupies the first 10 cm below the SWI and did notexhibit significant differences with depth. The main process affecting shellsurface was dissolution probably due to changesproduced by microbial maceration of organic matrix. Preservation was betterin saline lakes, which may allow to explain the high concentration ofwell-preserved shells usually found in Holocene sedimentary successions.