geologia e recursos naturais

Large meteorite impacts release kinetic energy that induces rock deformation, high temperatures and fluid circulation during the cratering process. To understand the correlation between rock deformation and fluid circulation, it is relevant to investigate
post-impact hydrothermal flux and its relation to the local geology. The Cerro do Jarau impact structure is a ~13.5 km diameter impact structure located in southern Brazil and formed on Cretaceous continental flood basalts of the Serra Geral Formation and

Fluvial erosion of the Earth's crust creates valleys ranging from hundreds of meters to a few kilometers wide. The resulting unloading is supported by the flexural rigidity of the continental lithosphere. As a result, the bending of the lithosphere around individual river valleys is usually imperceptible in the landscape, specially in tectonically quiescent environments.

This study refines the hydrogeological conceptual model of an area with three interconnected aquifers, namely the Crystalline Aquifer System (CAS - igneous and metamorphic rocks), which is in contact with the Tubarão Aquifer System (TAS - sedimentary rocks) and the Diabase Aquifer System (DAS – diabase rocks). The detailed investigation involved geophysical logging and hydraulic and hydrodynamic characterization with straddle packers in a local tubular well, in which groundwater presents high uranium concentrations.

Abstract

Cretaceous and possibly Paleogene strata, originally defined as the Alter do Chão Formation, are extensively exposed in the Amazonas Basin. While theoretical considerations suggest that the eastern Amazon has been draining into the Atlantic since pre-Miocene times, the limited published field data indicate a significant continental-scale reversal of drainage, transitioning from westward flow during the Cretaceous to the current eastward regional flow.