Edenilson Roberto do Nascimento

Knickpoint finder

This work presents a new software tool for morphometric analysis of drainage networks based on the methods of Hack (1973) and Etchebehere et al. (2004). This tool is applicable to studies of morphotectonics and neotectonics. The software used a digital elevation model (DEM) to identify the relief breakpoints along drainage profiles (knickpoints). The program was coded in Python for use on the ArcGIS platform and is called Knickpoint Finder. A study area was selected to test and evaluate the softwares ability to analyze and identify neotectonic morphostructures based on the morphology of the terrain. For an assessment of its validity, we chose an area of the James River basin, which covers most of the Piedmont area of Virginia (USA), which is an area of constant intraplate seismicity and non-orogenic active tectonics and exhibits a relatively homogeneous geodesic surface currently being altered by the seismogenic features of the region. After using the tool in the chosen area, we found that the knickpoint locations are associated with the geologic structures, epicenters of recent earthquakes, and drainages with rectilinear anomalies. The regional analysis demanded the use of a spatial representation of the data after processing using Knickpoint Finder. The results were satisfactory in terms of the correlation of dense areas of knickpoints with active lineaments and the rapidity of the identification of deformed areas. Therefore, this software tool may be considered useful in neotectonic analyses of large areas and may be applied to any area where there is DEM coverage. A software based on concepts of local and regional slope aids neotectonic analysis.Stronger knickpoint anomalies can be correlated to regional structures.Areas next to epicenters of Virginias recent quakes have higher knickpoint density.James Rivers course is very affected by regional structures and knickpoints.

Reativation of Taxaquara Fault and its morphotectonic influence on the evolution of Jordão River catchment, Paraná, Brasil

The Parana basin is one of the major morphotectures of the South American continent. Although its tectono-sedimentary evolution has been widely studied and fairly well understood, this paper aims to fill a gap in knowledge comprising the tectonic evolution after the end of its last sedimentary cycle, in the Upper Cretaceous. In this context, the Jordan River watershed, situated in the surroundings of Guarapuava municipality, south central region of Parana State, was selected for structural and morphometric analysis where the Cretaceous volcanic rocks of Serra Geral Formation are exposed. The Jordan River watershed was studied for the influence exerted by Taxaquara Fault Zone on its morphologic evolution, since Taxaquara Fault Zone is associated to the Brazilian cycle and extends eastwards to the Ribeira belt in the state of Sao Paulo. The morphometric analysis consisted in the interpretation of the Jordan River watershed drainage network and relief elements, considering the distribution of existing knickpoints in the water courses. Structural analysis was based on the calculation of the stress fields responsible for the activation of local fault zones, which were determined by their spatial arrangement and the statistical and mechanical treatments of structural data. During the Oligocene and Miocene, erosional processes developed a planing surface which marks the relief in the central region of the Jordan River watershed and serves as a stratigraphic marker for the associated deformational events. Three events that contributed to the morphological framework of the Jordan River watershed were defined: an oldest one, probably active before the development of the Jordan pediplane in the Paleogene, by a NE-SW maximum horizontal stress (SHmax); and two more recent ones, being one of Plio-Pleistocene age, with a N05W SHmax, and a still active event of transtensive nature showing a N75W SHmax. The paleostress analysis points to a similarity between the Cenozoic evolution of Parana Basin and the tafrogenic basins of southeast Brazil, revealing the amplitude of the deformation events associated to the studied period and ensuring the importance of further studies on the morphotectonic evolutions of intracratonic regions of the South American plate and their correlation to the Andean tectonic cycle.

Morphostructure of the Serra Do Mar, Paraná State, Brazil

ABSTRACT The morphostructural map of the Serra do Mar in Paraná was (Main Map) made of geologic and geomorphologic data obtained from fieldwork, satellite images, topographic data and information from previous studies. Six important escarpments limited by geologic structures, eight morphostructural units and four morphostructural domains were mapped. Kinematic data and the directions of the main families of faults, interpreted using digital elevation models, permitted us to characterize morphostructures that were generated by Cenozoic deformation events superimposed over older tectonic events. In many cases, we could also identify and map neotectonic features.

Azimuthfinder: ferramenta para a extração de dados e apoio na análise estrutural

Here is presented a computational tool named AzimuthFinder, for functioning inside the set of programs of ArcGis®. The developed program is intended to facilitate and optimize the generation of azimuth data tables, using structural lineaments previously traced in maps that are being worked on that automatic information system. The characteristics of AzimuthFinder allow that, upon the users choice, different tables get generated for the same analysis object, depending on the relative weight attributed to the lineaments, giving for example greater weight to those of greater extension. Another characteristic of the tool is the file exportation in TXT format, which is universal to several types of programs, with specific formatting to one the software between Stereo32, Win Tensor, OpenStereo and StereoNet7, which are all free software prepared to the confection of rose diagrams. Tests with the program showed that it is very efficient and fast for generating the azimuth data tables, effectively allowing easier confection of rose diagrams, which are necessary for the structural analysis in areas submitted to fragile deformation.