INQUISAL   20936
INSTITUTO DE QUIMICA DE SAN LUIS "DR. ROBERTO ANTONIO OLSINA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PALEOEDAPHOCLIMATIC INFERENCES IN A LOESSIC COLUMNAR SUCCESSION OF THE SAN LUIS MOUNTAINS, ARGENTINA
Autor/es:
STRASSER, E; CHIESA, J.; OSTERRIETH, M; MARCHEVSKY, E; PERINO, E.
Lugar:
Potrero de los Funes
Reunión:
Congreso; XXX Reunión Anual de la Sociedad de Biología de Cuyo; 2012
Resumen:
The Pancanta pedostratigraphic profile in the San Luis mountains
(32º51S; 66º07W; height: 1617m) is representative of the loessic
sedimentation at the pampas. The moisture regime of the soil is udicmesic.
The climate variables condition a positive water balance that
generates reserves in the soil of 25 - 50mm for 10 months/year. The
main objective is to infer the variations of the paleoedaphoclimatic
conditions in a registry of about 12k years BP and compare them
with the present ones. In 14 samples, 22 elements (majors, minors
and trace) were quantitatively determined by wavelength dispersive
X-ray fluorescence (XRF) techniques. The material was separated
by specific weight of d< 2,3g.cm-3. The identification and optical
microscopy semicuantification of silicophytoliths morphotypes was
performed. Two paleoedaphic levels were recorded by C14 (conventional).
Three levels with chemical alteration index (CAI = 63%)
were determined for which a development under edaphoclimatic
conditions, similar to the present, is inferred. At At the sampling
mean depth (-98cm), a radiocarbonic age of: 2910 ± 90 years C14
BP and CAI = 64%; a (-60cm) 1270 ± 50 años C14 BP and CAI =
67%, was determined. A certain correlation between total
silicophytoliths concentration, paleoedaphic levels and Zn/Ni ratio,
was observed, as meteorization products.