Banca de QUALIFICAÇÃO: GENISSON PANTA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : GENISSON PANTA DA SILVA
DATE: 30/08/2021
TIME: 14:00
LOCAL: Videoconferência
TITLE:

Topographic expression. of structural control and response to base level fall in Proterozoic Basement: Meridional Sertaneja Depression, Lower São Francisco River.

KEY WORDS:

incision, semiarid, morphometry, planation surface.

PAGES: 75
BIG AREA: Ciências Humanas
AREA: Geografia
SUMMARY:

A large number of studies of planation surfaces on high-elevation passive margins have listed river incision into bedrock as one of the determining factors for long-term landscape evolution. These rivers are expected to communicate important geological processes in the erosive landscapes, such as base level fall, for example. However, in the low elevation exposed shield regions, it is usually said that rivers play a supporting role in the relief design. Rivers, in this context, are routinely described as transport agents for pre-weather material, with the control of the topography being the responsibility of the climatic regime and the denudation rates of old structures. Although, from the understanding physical mechanisms of fluvial erosion into bedrock, there seems to be no doubt that its importance goes beyond sediment transport. This study aims to analyze the fluvial topography of bedrock rivers that drain the Southern Sertaneja Depression, a low-elevation pervasive surface over a Proterozoic shield that borders the Borborema Plateau, in the semiarid region of northeastern Brazil. We sought to investigate the morphology of the longitudinal profiles, map knickpoints, estimate the magnitude and spatial distribution of the vertical incision of river valleys and evaluate the contribution of previous controls on these morphologies. All these analyzes were applied on morphometric techniques based on Digital Elevation Model (DEM), such as the extraction of the Normalized Steepness Index (K_sn) and the Slope-Length Ratio (SL), in addition to the quantification of the hillslope angle, analysis of topographic and drainage photolineaments, integral and hypsometric curve, local relief, among others. The rivers to be studied are all tributaries on the left side of the lower course of the São Francisco River, one of the largest rivers on the planet. This great river carved out a canyon in the study area. From this, the hypothesis that guides this study is that the lowering of the base level promoted by the incision of the São Francisco River in the planation surface in Proterozoic shield promoted an incision wave that is propagating towards the headwaters of the tributary rivers and is expected to find a pattern of systematic distribution of knickpoints in the profiles that reflects this process. Otherwise, this assumption will be invalidated and, alternatively, other processes may have been responsible for shaping the longitudinal profiles of the tributary network, such as the contact between lithologies. The circumstances that led to the carving of the São Francisco River canyon have not yet been defined, but this study will also outline considerations on this topic.

BANKING MEMBERS:
Externo à Instituição - ANTONIO CARLOS DE BARROS CORRÊA - UFPE
Presidente - 1891214 - KLEYTHON DE ARAUJO MONTEIRO
Interna - 1574934 - NIVANEIDE ALVES DE MELO FALCAO