Saltpan Surface Variations Analysis With RADARSAT-2 Data
Daniela Marchionni(1), Gustavo Martinez(2), Miguel Del Blanco(1) and Francois Cavayas(3)
(1) Instituto de Recursos Minerales (UNLP-CIC), Calle 64 e/119 y 120, La Plata (1900), Argentina
(2) Centro de Geología de Costas y Cuaternario, C.C. 722, Mar del Plata (7600), Argentina
(3) Département de Géographie, Université de Montréal, Succ. Centre Ville, Montréal, Québec (H3C3J7), Canada
The aim of this paper is to present the lineaments and background of a project called “Saltpan surface variations analysis with RADARSAT-2 data” (2643 SOAR). The main goal of this project is to make use of polarimetric RADARSAT-2 data for landscape and environmental analysis of salt bodies in the southern part of Buenos Aires province, Argentina. This project have been incorporated as a new branch of a main project “Geology and Mineralogy of Salt Bodies of the Pampas Region” which is one of the regular research activities that INREMI carries out since 1988.
The southern part of Buenos Aires province is a region of flat or slightly undulate morphology, where some morphological depressions, frequently aligned NW-SE, that lodge salt bodies, have been developed. The semi-arid conditions of this area have facilitated the concentration of evaporite minerals to constitute temporary saltpan deposits, sometimes with negative altitude referred to the near sea level. The mineralogical composition of them is dominated by halite, with intercalations of gypsum, clastic materials and organic matter and, in some cases, glauberite. Most of these saltpans are composed by salt flats and mud flats and surrounded by sand flats, ravines and aeolian deposits. These deposits are in continuous change where different environmental agents acts: superficial waters, deep aquifers, wind, temperature, moisture, etc. Within the salt deposits, depending on their origin and the evolution stage, different kinds of surfaces could be differentiated; they could vary in the mineralogical proportion and composition, the concentration and density of brine, the clastic materials contribution, the thickness of evaporite layers, the texture of evaporite minerals, etc.
Within this context we expect to: a) test polarimetric RADARSAT-2 data discrimination and mapping potential applied to salt pan surfaces, using roughness, moisture content, texture and mineralogy variations, at different observation scales (Standard SDP, Fine QP and Multi Look Fine SSP modes), b) make use of polarimetric RADARSAT-2 data to analyse environmental conditions influences in the genesis and evolution of the evaporite deposits due to their dependence on weather conditions and hydrological regimes (winter and summer images, to analyze and monitoring the evolution and seasonal changes because of their dependence on the environmental conditions, and c) to establish a methodology to routinely map salt pan surface characteristics and extension and to monitor the evolution and cyclic changes of salt bodies.