MORPHOLOGICAL CHARACTERIZATION AND ENVIRONMENTAL DYNAMIC OF WEATHERING PITS IN FAZENDA NOVA DISTRICT, STATE OF PERNAMBUCO, NORTHEAST OF BRAZIL

da Silva, Danielle Gomes , Correa, Antonio Carlos de Barros , Amorim, Rodrigo de Freitas

2017 REVISTA BRASILEIRA DE GEOMORFOLOGIA 2017   18(卷), 2(期), (349-362页)

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Closed depressions - weathering pits -, developed on crystalline lithology are found in many regions of the planet. In the State of Pernambuco, weathering pits were found in 37 municipalities. As they are being studied in other sectors of the semiarid region of Brazil, weathering pits have served as important data sources for the reconstruction of recent geomorphological landscape histories, based on the study of their sedimentary infill. In this regard, this work aims at interpreting, by means of the morphological analysis of landforms, the genesis and dynamics of relief in the area of Fazenda Nova, Brejo da Madre de Deus municipality, State of Pernambuco. Weathering pits in the study area are generally associated to coarse grained granite inselbergs, occurring along the intersections of fracture lines, and morphologically restricted to intermontane pediments of flat topography in the vicinity of hillslope knick points. The sedimentary infill of Inco weathering pit derived from unchanneled debris flows, formed under torrential conditions, thus showing that this aggradational record is related to alternating cycles of pedogenesis/morphogenesis under differing levels of semi-aridity occurring in the area since the penultimate glacial maximum.