Intensidade da atividade tectônica na porção emersa da Bacia Paraíba e embasamento cristalino adjacente, Nordeste do Brasil

Abstract

Estudos realizados em diferentes contextos geomorfológicos da Terra têm demonstrado a eficácia da aplicação de dados geomorfométricos extraídos a partir de modelos digitais de elevação para a identificação de feições do terreno sugestivas de deformação tectônica. Este estudo aplica índices geomorfométricos na avaliação da intensidade tectônica de depósitos sedimentares da porção emersa da Bacia Paraíba e do embasamento cristalino adjacente, nordeste do Brasil. A partir da base digital da rede de drenagem e do modelo digital de elevação da Shuttle Radar Topography Mission (SRTM) foram empregados os índices: relação declividade-extensão (RDE), fator assimétrico (Af), integral hipsométrica (Hi) e sinuosidade de frente de montanha (Smf). Os resultados possibilitaram distinguir e espacializar classes de intensidade de deformação tectônica por meio do índice de atividade tectônica relativa (Iat). Os dados revelaram tectonismo mais intenso em unidades sedimentares neógenas e quaternárias localizadas na porção nordeste da área estudada.

Morphostructural influence and neotectonic activity in the geomorphological configuration of southeast Paraíba and northeast Pernambuco, Brazil

“…The analysis of the AFI in the study area revealed the presence of sub-basins exhibiting low, medium, and high levels of asymmetry, with AFI values categorized as 0 to 30 (25 %), 31 to 50 (31 %), and greater than 51 (44 %), respectively. These findings are in agreement with the research conducted by Andrades Filho and Rossetti (2015) [ 35 ] and Silva and Furrier (2019) [ 43 ], who reported that 58 % of basins in the northeastern region of Paraíba demonstrated asymmetry under conditions of tilting or inclination. Regarding the AFI index, across the basins surveyed in the southeastern sector of Paraíba, 82 % exhibited asymmetry intensities ranging from medium to high.…”

“…Using this approach, straight lines were drawn connecting the headwaters and mouth of each channel, facilitating the creation of a profile incorporating the altimetric data of these points. To evaluate the severity of anomalies in the selected channels, the methodology outlined by Andrades Filho and Rossetti (2015) [ 35 ] was employed, which identifies channels as anomalous when their RDE real (RDE segment /RDE total ) ratio is equal to or greater than 2. This parameter is calculated based on the altitudinal difference between two extreme points of a segment along the watercourse, essentially representing the elevation change from the river's source to its mouth, as depicted in Figure S3 (Supplementary Material) .…”

Using morphometric and geomorphic indices to assess Western São Francisco Craton neotectonic traces

“…Except for the Cana-brava creek, the other courses drain smaller catchments, and the HI values indicate that streams flow over a resistant lithology. Notably, the HI values for Assapeixe and Caiçara creeks indicated active dissection, maybe rejuvenated areas; these results are consistent with analogous of the Araripe and Paraíba sedimentary basins, where HI > 0.50 were used to select erosion-prone sub-catchments and support the hypothesis of neotectonic activity in a composite index ROSSETTI, 2015;OLIVEIRA et al, 2018).…”

“…In the profiles of the left bank tributaries, hanging valleys are observed only in the Morro Redondo creek, emplaced by a knickpoint associated with the fold-and-thrust terrain of the NNW-SSE shear zone. Suggestive of relative tectonic activity (EL HAMDOUNI et al, 2008), at the southern boundary of Southern Amazonian Craton, and inside the Paraíba and Araripe sedimentary basins, SL/K > 6 support lowrate neotectonic reactivation report ROSSETTI, 2015;OLIVEIRA et al, 2018;ALMEIDA et al, 2020).…”