Palaeohydrology of the Quaternary saline Lake Ballivian (southern Bolivian Altiplano) based on diatom studies |
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| Authors: | S Servant-Vildary S H Mello e Sousa |
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| Institution: | (1) Antenne ORSTOM, Laboratoire de Géologie MNHN, 43 rue Buffon, 75005 Paris;(2) Instituto Oceanografico, CEP OSSOB, USP, Sao Paulo, SP, Brésil |
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| Abstract: | Diatoms are usually used for reconstructing variations in past lacustrine depth. In a small endorheic basin located in the
southern Bolivian Altiplano, we used a comparative method based on basin morphology, stratigraphy, sediment samples, altitude
and diatom ecology to infer depth variations more precisely in both marginal and central parts of the basin. Beforeca. 22,000 yr BP, the general tendency was a progressive increase in water-level from 4,135 to 4,155 m altitude, but Lake Ballivian
rose to 4,160 m twice, and dropped below 4,135m twice. After ca. 22,000 yr BP, a long dry period occurred, as indicated by
a sedimentation hiatus. Atca. 13,000 yr BP, the water-level slightly increased again but the lake stayed very shallow, at less than 4,125 m altitude.
*** DIRECT SUPPORT *** A02GG003 00005 |
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| Keywords: | Quaternary diatoms palaeohydrology |
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