Abstract

HORTA, Luis Rubén  and  GEORGIEFF, Sergio M.. SEDIMENTOLOGICAL CHARACTERIZATION AND AGES OF THE PLEISTOCENE - HOLOCENE LACUSTRINE DEPOSITS NORTHWEST SANTA CRUZ, ARGENTINA. Ser. correl. geol. [online]. 2016, vol.32, n.2, pp.1-10. ISSN 1666-9479.

This paper compares se-dimentological characteristics and radiometric ages of the Late Pleistocene and Holocene deposits cropping out surrounding to Pueyrredón - Posadas - Salitroso Lacustrine System (PPS-LS, NW of Santa Cruz province, Argentina). Six detailed stratigraphic profiles were measured and sampled in order to understand the PPS-LS evo-lution. The organic matter of fine sediments was dated using the AMS & 14C methods. In fourteen samples of clays, silts, and sands (located at different heights, 400, 300 and 200 masl) were realized grain size analysis, which allowing distinguish between subaerial and subaqueous (shallow and deep) areas in the basin. The gra-in sizes analysis integrated with facies associations indicate as sedimentary paleoenvironments (lacustrine, gla-ciolacustrine or coast lake) as the linkage among sedimentary bodies and also identify the paleolake fuctuations. In general, coarsening-upward variations in PPS-LS are interpreted as shallowing lake cycles related to the regional fall of baselevel lakes in East - West direction from Late Pleistocene (ca. 25,000 yrs. BP) to Holocene.

Keywords : Sedimentoloey. Lacustrine system. Pleistocene - Holocene. Argentine.

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