The origin of gley colors in hydromorphic vertisols: the study case of the coastal plain of the Río de la Plata estuary

This work aims to contribute the interpretation of soil colors; mainly identify pigments that generate greenish colors in hydromorphic conditions (gley colors) vertisols coastal plain Río de la Plata estuary. These are cold hues, generally (olive-gray), and occur poorly drained soils with prolonged water accumulation. For this purpose, samples Bssg horizons from estuary were analyzed using routine chemical analyses, Mössbauer spectroscopy, determination rocks magnetic parameters, X-ray diffraction, thermogravimetric differential thermal analysis petrographic-electronic microscopy. The associated gley these due ferric iron content, corresponding minerals such as iron-rich smectites (nontronite/Fe-rich beidellite) oxy-hydroxides like goethite, which range green yellow. minerals, combined gray or black components, e.g., manganese compounds and/or organic matter, generation usual Pampean plain. obtained data allows us state it is a mistake assing olive color presence ferrous compounds, traditionally done. oxidizing condition dominant all samples, integrating composition clay (goethite).