Abstract

ORGEIRA, María Julia  and  COMPAGNUCCI, Rosa H.. The use of the magnetic signal of soils and paleosoils as a climatic function. Rev. Asoc. Geol. Argent. [online]. 2009, vol.65, n.4, pp.612-623. ISSN 0004-4822.

The correlation between an index of potential water storage (PWS) with magnetic signal in soils and paleosoils, developed in loessic sediments has been proposed. The analyzed data suggest the existence of climatic thresholds that affect the genesis, preservation or depletion of ferrimagnetic minerals. Soils and paleosoils characterized by a positive PWS have an appropriate environment that favors the depletion of ferrimagnetic minerals due to mainly reductive loss. Such soils are characterized by a depletion of detrital ferrimagnetic minerals, as in northeastern Pampean plain soils and paleosoils of Argentina and SE of China. A negative PWS prevents highly reducing conditions in the soil, and the detrital ferrimagnetic minerals are preserved. On the other hand, the environmental conditions of these soils allow the formation of new nannoparticle minerals. These conditions produce a net magnetic enhancement of the soil, as observed in European soils (Russia, Czech Republic, Rumania), Asian (paleosoils from the loess plateau of China) and Northern African ones (Tunisia). The influence of parent material in the magnetic signal is also discussed.

Keywords : Magnetism; Paleoclimate; Late Cenozoic; Paleosoils.

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