Geomorfología y sedimentología de la Cuenca Superior del Río Salado (Sur de Santa Fe y Noroeste de Buenos Aires, Argentina)

the geomorphology, late quaternary stratigraphy, sedimentology and hydrology of the upper basin of the salado river were investigated. the study area is located in s santa fe and nw buenos aires provinces (11.000 km2) and comprises the ne sector of the pampean sand sea (defined by iriondo and kr？hling, 1995; figures 1 and 2). the methodology applied in this study produced conclusions of stratigraphic and paleoclimatic nature. works were performed in photographic and images cabinet, in the field and laboratory. in cabinet, the geological cartography produced by the first author in former projects was issued, particularly the geological map of santa fe province, in 1:500.000 scale (iriondo, 1987; figure 3), the map of the south american plains (iriondo, 1990a; petit maire et al., 1999) and the map of the pampean sand sea in scale 1:1.000.000 (iriondo, 1992). that was complemented with satellite images and photomosaic analyses, integrated with classical topographic quadrangles of igm. field works made in the region covered a period of two decades. the first expedition was done in the year 1985, during a dry inter-annual period which favored the description of geological profiles and collection of fossils in the bottom of channels. further expeditions were made in the 1990's, resulting in the elaboration of the regional stratigraphy (figure 4; kr？hling, 1998; iriondo and kr？hling, 1995). the last three field surveys, between the years 2001 and 2004 (during the present humid period), were focused on the studies of dune fields, with areal sampling (about 50 samples) and the recovering of sedimentary cores (41 m drilled). four stratigraphic boreholes were made in the study area and a complementary one outside it, with recovering of undisturbed samples and complemented with geotechnical s.p.t. tests. the main boreholes were drilled in teodelina (34°11′lat. s; 61°31′long.w; 88 m a.s.l.; santa fe; figure 5) and in san gregorio (34°17' lat. s y 61°55′ long. w; 102 m a.s.l, san