Earth Planets Space, Vol. 58 (No. 10), pp. 1381-1387, 2006
Carlos A. Vasquez1,2 and Hugo G. Nami2,3
1Ciclo Básico Común, Universidad de Buenos Aires.Ciudad Universitaria (Pabellón III), (1428) Buenos Aires, Argentina
2CONICET--Instituto de Geofísica "Daniel A. Valencio", Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (Pabellón II), (1428) Buenos Aires, Argentina
3Associate Researcher, Deparment of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington D.C., 20560, U.S.A.
(Received December 22, 2005; Revised June 4, 2006; Accepted June 5, 2006; Online published November 8, 2006)
The magnetic characteristics of soils are widely used in environmental and paleoclimatic investigations for studying the several factors involved in the soil formation process. We propose here a new analytical tool that takes into account the variations in magnetic properties correlated with grain sizes and concentrations of ferrimagnetic minerals. This analytical tool is based on a mathematical model of well-established magnetic properties in samples of known grain sizes and was used in this study to determine changes in the grain size and concentration of ferrimagnetic minerals along a terminal Pleistocene/Holocene fluvial section located in the northeast of Buenos Aires province. These variations may reflect a humid period prevailing in the area and may be associated with climate changes that occurred in the Chaco-Pampean region during the Middle Holocene.
Key words: Rock magnetism, Magnetite, Titanomagnetite, Holocene, Buenos Aires.