%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture non répertoriées par l'AERES
%A Sylvestre, Florence
%A Servant Vildary, Simone
%A Fournier, Marc
%A Servant, Michel
%T Lake levels in the southern Bolivian Altiplano (19°-21°S) during the Late Glacial based on diatom studies
%D 1996
%L fdi:010025538
%G ENG
%J International Journal of Salt Lake Research
%K FLORE ; DIATOMEE ; FOSSILE ; STRATIGRAPHIE ; PALEOCLIMAT ; NIVEAU DE L'EAU ; SALINITE ; SEDIMENTATION GLACIAIRE ; SEDIMENTATION FLUVIATILE ; MILIEU LACUSTRE
%K BOLIVIE ; ANDES
%K ALTIPLANO REGION
%P 281-300
%R 10.1007/BF01999113
%U https://www.documentation.ird.fr/hor/fdi:010025538
%> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_57-58/010025538.pdf
%V 4
%W Horizon (IRD)
%X This study is focused on the endorheic Uyuni-Coipasa Basin located in the southern Bolivian Altiplano. Stratigraphical and fossil diatom studies based on a detailed radiocarbon chronology revealed six phases in water-level changes and paleosalinity variations. At 15,430 +- 80 yr B.P., lacustrine conditions settled in the southern Bolivian Altiplano. A saline lake, characterized by benthic meso-metasaline species, reached +4 m altitude above the present bottom of the basin. After 15,430 +- 80 yr B.P. the level rapidly rose to + 27 m, as suggested by a tychoplanktonic mesoline flora. Between 14,500 years and 13,000 years, finely lamited sediments at + 32 m contained successively a dominance of epiphytic mesosaline to hypersaline species and tychoplanktonic oligosaline diatoms, indicating weak fluctuations in water-level and salinity. At 13,000 years, strong changes in the diatom flora occurred: epiphytic oligo-hypersaline diatoms were replaced by planktonic meso-polysaline species. They indicate a deep salt lake (the lake level reached + 100 m). After 12,j000 yars, the lake level abruptly dropped, as suggested by fluviatile sediments with a benthic mesopolysaline diatom flora. The main lake was replaced by shallow saline ponds. A wet pulse occurred at 11,400 years, characterizad by low water level ( + 7 m) and high salinity. This lacustrine phase remained until 10,400 yr B.P. These data indicate changes in Precipitation minus Evaporation (P-E). Our regional interpretations are based on a comparison with the available data on the northern (Lake Titicaca) and southern (Lipez area) Bolivian Altiplano and on the northern Chilean Altiplano (Atacama Desert). (Résumé d'auteur).
%$ 064GEOQUA