Solubility and speciation of Iron present on top soil from the Puna-Altiplano area

L. SIMONELLA; M. PALOMEQUE; G. ROMÁN ROSS; E. LEGARRA SAEZ; J.A. SANS TRESERRAS; D. GAIERO

Mendoza

Congreso; I18th International Sedimentological Congress - Mendoza, Argentina, 2010; 2010

IAS - International Association of Sedimentologists

During the last decade a great deal of effort has been devoted to establish the effects of mineral dust on global and regional climate. In this sense, it is recognized that wind-blown dust has the potential to significantly in - fluence the biological activity in the oceans (the “iron hypothesis”) and the regional climate by blocking the sunlight and changing cloud properties (radiative forcing effect). In order to evaluate the effect of mineral dust from Southern South America(SSA), Prospero et al. (2002) recognized three main source areas that are correlated with the arid diagonal: Puna-Altiplano (PAP) (15 ° -26 °S), west-central Argentina (27 º -35 ºS) and Patagonia (39 º - 52 ºS). The Puna region reaches the highest elevation (average 4400 m) and at the latitude of ~25°S it is crossed by the subtropical jet stream (tropospheric westerly). This stream reaches its maximum intensity during winter and early spring, allowing the development of huge storms which deflate large amounts of sediments. Between 1995-2008, a total of 50 surface soil samples were collected from the areas recognized by Prospero et al. (2002) with the aim of defining mineralogical, chemical, isotopical and textural characteristics. In the present work 5 samples from PAP were studied in order to determine the speciation and availability of Fe. With the goal of evaluating the biogeochemical balance of Fe in the ocean, studies of sequential extractions were carried out. It has been shown that the mineralogy (Journet, et. To 2008) and the particle size (Ooki, et. To 2009) are critical in solubility studies. Therefore, the samples were divided into three fractions according to particle size (