Abstract

BIDEGAIN, J.C.; OSTERRIETH, M.L.; VAN VELZEN, A.J.  and  RICO, Y.. Geology and magnetic records between Arroyo La Tapera and Santa Clara del Mar, Mar del Plata. Rev. Asoc. Geol. Argent. [online]. 2005, vol.60, n.3, pp.599-604. ISSN 0004-4822.

Paleomagnetic studies were carried out in Pleistocene-Holocene sedimentary sequences exposed between Arroyo La Tapera and Santa Clara del Mar in Mar del Plata. The sediments exposed in the lower part of the La Tapera and Camet sections, which apparently belong to the Ensenada Formation, show reverse polarity directions and are assigned to the Matuyama Polarity Chron. The sedimentary layers exposed at the base in Santa Clara del Mar present normal directions of polarity, hence they were consequently assigned to the Brunhes Polarity Chron (< 0,78 Ma). Susceptibility values show a similar behaviour to those obtained in other localities of the Argentine loess plateau. Lowest values are always related to stronger pedogenesis and weathering. Consequently we envisage that the windblown titanomagnetites, having settled out during drier glacial periods, account for the natural magnetic remanence and the higher susceptibility values in less weathered layers.

Keywords : Paleomagnetism; Brunhes; Matuyama; Loess; Paleosols.

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