Forma e ocorrência dos escapes gasosos no Remanso do Fogo/Bacia do São Francisco: uma análise a partir de dados multifontes de alta resolução espacial e espectral

This paper describes the combined use of gasometric data, terrestrial radiometric data, reflectance spectroscopy data and ProSpecTIR-VS hyperspectral imagery to characterize soils and vegetation anomalies due to the presence of natural seepages in the São Francisco Basin, a region known as Remanso do Fogo. The locations of seeps were mapped using image processing techniques and the results demonstrated that the absorption bands of kaolinite and iron oxides/hydroxides can be used for that purpose with some limitations. Although hydrocarbon anomalies increase the content of kaolinite and decrease the content of iron oxides, drainage systems and the relief can mobilize minerals in soils, thus encumbering their correlation with gas seeps. In such situations vegetation anomalies as well as gamma ray anomalies (Higher DRAD and Ures, lower Kres) may be used as determinative vectors of the existence of seeps. The combined use of multi-source data in the characterization of soils and vegetation submitted to natural gas seeps in the region of Remanso do Fogo provided a better comprehension of changes induced in soils and in vegetation by the presence of gases in soils, based on a greater detailing of spectral features of interest.