INVESTIGADORES
PAGANI Maria Alejandra
congresos y reuniones científicas
Título:
The Lanipustula Biozone in Patagonia: stratigraphic extension, faunal changes, paleoclimatology and paleoecology
Autor/es:
PAGANI, M.A.; TABOADA, A. C.; ISBELL, J.; FRAISER, M.L.; DINEEN, A.A.; PAULS, K.N.
Lugar:
General Roca
Reunión:
Congreso; Reunión Anual de Comunicaciones de la Asociación Paleontológica Argentina; 2012
Institución organizadora:
Asociación Paleontológica Argentina
Resumen:
The Pampa de Tepuel and Mojón de Hierro formations in the Tepuel-Genoa Basin (Patagonia) constitute a succession that may contain as many as 6 glacimarine and glacially-influenced marine horizons separated by non-glacial intervals. Thus, these strata represent the thickest and most complete record of polar conditions for the Late Paleozoic Ice Age (LPIA). The Lanipustula Biozone is recognized in the Pampa de Tepuel Formation. ThePampa de Tepuel Formation was deposited in a possible shelf edge and slope setting. Coarse clastics would have been introduced into the sites during possible sea level lowstand; while shales were deposited during transgressive and highstand systems tracts. Diamictites are weakly stratified to massive with striated clasts suggesting deposition of fines from meltwater plumes and coarse particles as iceberg rafted debris. Diamictites were also deposited by debris flows. Grooved surfaces are the result of slide/glide planes and possible iceberg keel marks. The Lanipustula Biozone is at least 450 m thick and four fossil-bearing levels are recognized, in all of them the Lanipustula patagoniensis Simanauskas (1996) is recognized, but the diversity, abundance and faunal composition changes from the base to top. Upward, faunal changes represent changing environmental and paleoecological conditions. The lowstand may have allowed for more oxygenated and possibly brackish waters due to the proximity of shallower agitated waters and the introduction offreshwater from glaciers and deltas. The slump and slide blocks as well as “turbidity currents” and possible bottom currents may have brought oxygen into the area where these features are present.