INVESTIGADORES
PEREZ Alejandra Patricia
artículos
Título:
Late Quaternary Environmental Changes in Patagonia as Inferred from Lacustrine Fossil and Extant Ostracodes
Autor/es:
GABRIELA C. CUSMINSKY; ANTJE SCHWALB; A. PATRICIA PÉREZ; DANIELA PINEDA; FINN VIEHBERG; ROBIN WHATLEY; VERA MARKGRAF; A. GILLI; DANIEL ARIZTEGUI; F. S. ANSELMETTI
Revista:
Biological Journal of the Linnean Society
Editorial:
The Linnean Society of London
Referencias:
Lugar: London; Año: 2011 vol. 103 p. 397 - 405
ISSN:
1095-8312
Resumen:
In the present study, we compare modern and Quaternary ostracods from two lacustrine basins: Laguna Cari-Laufquen (41°S) and Lago Cardiel (49°S) in Patagonia. Taxonomic and quantitative analyses along with isotopic and chemical studies of the extant ostracod fauna indicate that distinct ostracod associations can be identified as a function of conductivity. Three ostracod associations can be distinguished: (1) springs, ponds and small creeks, characterized by low conductivity (e.g. 1015 us cm-1); (2) lakes and permanent ponds, characterized by medium conductivity (e.g. 1625 us cm-1) and (3) ephemeral lacustrine environments, generally characterized by higher conductivity (e.g. 16 480 us cm-1) These modern ostracod associations were also identified in older sequences from sediments outcropping in the Laguna Cari-Laufquen current shoreline, as well as in sediment cores from Lago Cardiel. The predominance of Limnocythere rionegroensis Cusminsky & Whatley in the Cari-Laufquen sections suggests the development of a saline and turbid lake during the Late Pleistocene and Early Holocene, and thus higher precipitation at these latitudes. Changes in ostracod abundance and associations have been observed in Lago Cardiel during the last approximately 16 000 calibrated years BP. Conductivity is known to change as a function of the ratio of precipitation to evaporation and a decrease in conductivity from the Late Pleistocene to the Middle Holocene suggests substantial hydrological variations (i.e. increase of the precipitation/evaporation ratio suggests minor conductivity). These two examples show that ostracods provide an excellent proxy for interpreting palaeoclimatic and palaeoenvironmental changes in Patagonia.