Gypsum classification based on ASTER images in the Principal Cordillera of Mendoza

A combination of two methodologies is presented for detection and mapping of gypsum using ASTER L3A imagery. One of the methodologies uses the Quartz index defined for the ASTER TIR subsystem, which can be used for gypsum detection given its low response in Qi. The other consists in the combination of two band ratios of the ASTER SWIR subsystem, (4/5)/(7/5), which allows the identification of gypsum highlighting its high response in 4/5 and low response in 7/5. Two areas in the Cordillera Principal in the province of Mendoza were selected as case studies, and a field survey was conducted in order to evaluate the results. Both techniques are proved successful, yet classify erroneously some pixels as gypsum. Errors by excess are different for each method, which allows for these two techniques to be combined using a "decision tree" classifier to solve the misclassifications.Fil:Mescua, J.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Stratigraphy and structure of the río Borbollón area, Mendoza

Results of a detailed geologic survey of the Río Borbollón area, located in the Cordillera Principal of the province of Mendoza are presented. The stratigraphic record of the area corresponds to a Jurassic-early Cretaceous sedimentary succession, the products of Neogene igneous activity and Quaternary deposits. The Tres Esquinas and La Manga Formations of Jurassic age were recognized for the first time in the study area. The main structural features of the area are described and interpreted based on the obtained data and previous works. A balanced structural cross section of the Malargüe fold and thrust belt at 34°15'S depicts the structural style and the amount of orogenic shortening in this region of the Andes.Fil:Mescua, J.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Ramos, V.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Extensional tectonic evidences in the upper Jurassic (Kimmeridgian) in south-western Mendoza province

This contribution presents the results of a first stage of a study of the Tordillo Formation in southwestern Mendoza province. This unit, assigned to the Kimmeridgian, represents a continentalization of the Neuquén Basin. It consists mainly of fluvial deposits associated with eolian and playa lake deposits. The reconstruction of the thickness variations of this unit, the presence of synsedimentary normal faults and a provenance study in sandstones from two localities, which shows that sediment supply came from both margins of the basin, suggest that the Tordillo Formation was deposited during an extensional period, in a similar way to what is observed in the Cerro Aconcagua area and in the Sexta Region in Chile.Fil:Mescua, J.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Giambiagi, L.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Bechis, F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina