Lacustrine ostracoda and late Quaternary palaeoenvironments from the lake Cari-Laufquen region, Rio Negro province, Argentina.

WHATLEY, R. C.; CUSMINSKY, G. C

PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY

Elsevier

Lugar: Amsterdam; Año: 1999 vol. 151 p. 229 - 239

0031-0182

Results are presente from a preliminary analysis of late Pleistocene ostracod bearing samples form a lacustrine section collected in the Maquinchao valley in the Cari-Laufquen lake region (lat. 41º35´S; long. 69-º25´W) situated 150 km east of San Carlos de Bariloche on the northern Patagonian steppe. The rich lacustrine ostracod fauna, obtained during the Lagos -Comahue project, has yielded important climatic and environmental information of the late Pleistocene and Holocene of northern patagonia. The fauna comprised mainly new species of Limnocythere and Eucypris. During the last 13,200 years B. P. (thermoluminiscense dating), levels representative of much more humic conditions than those obtained at the present time, are suggested by stratigrafphical levels which include those yielding a very abundant fauna of Eucypris fontana (Graf) and Limnocythere rionegroensis  Cusminsky and Whatley. These humic climatic levels are overlaim by a sequence in wich the ostracod faunal abundance decreases very abruptly and this event coincides with the appearance fo evaporites suggesting the onset of significantly drier condititions during the Holocene.