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Stream gradient investigation in the Bükkalja using interpolated surfaces
23-36Views:184The geological, tectonic settings of an area can be examined with the analysis of drainage network. In the Bükkalja, the Miocene pyroclasts – mainly the welded ignimbrites – had taken decisive part in the evolution of drainage network. For the confirmation of their role, the breakpoints of stream profiles were analysed. However this method provides information only about the direct surroundings of the creeks. In the aim of getting informations about the areas between the streams, surfaces were interpolated from stream gradient data and analysed as stream gradient maps. The stream gradient data were calculated with Hack J.T.’s formula, but due to the false results it was necessary to modify this formula and to recalculate the values. According to the map interpolated from the modified stream gradient values, there is a clearly identifiable relationship between the location of the welded ignimbrites on the surface, and the gradient values. Areas with high values are on the eastern part of the study area, where these pyroclasts can be found, while in the west, where the surface is covered by less resistant rock types, the gradient values are much lower.
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Integrated approach for lineament extraction in assessing groundwater potential: a case study in the highlands of Eritrea
1-14Views:156Groundwater exploration is crucial for sustaining ecosystems and human activities, particularly in semi-arid regions like the highlands of Eritrea. This study evaluates the effectiveness of manual and automated lineament extraction methods for identifying geological structures indicative of groundwater potential. Using a 30-meter resolution SRTM digital elevation model (DEM), we generated hillshade images and extracted lineaments manually by ESRI ArcGIS and automatically with MATLAB's edge detection algorithms, including Canny, Sobel, Prewitt, Roberts, Approximate Canny, and Laplacian of Gaussian (LoG). Our findings reveal significant differences between the manual and automated methods. Directional analysis showed that manually identified lineaments primarily followed NE-SW and NW-SE directions. Among the automated methods, Canny, Approxcanny, and Prewitt exhibited similar directional trends. Lineament density maps indicated high-density areas in the western and northern parts of the study area for both manual and automated methods. The LoG algorithm showed the highest correlation (0.8561) with the manual method, suggesting it as a reliable alternative for lineament mapping, contributing to more efficient groundwater exploration in semi-arid regions.
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Remnant surfaces in the Tárkány Basin
20-30Views:297The terraces of the Tárkány Basin, located in the SW part of the Bükk Mountains are known since the beginning of the 20th century. Based on field surveys, six morphological levels were delineated and described in 1936. During the later geological mapping surveys, three gravel terraces had been mapped in the basin. Since then, no comprehensive morphological mapping has been made in the Tárkány Basin. Our study aimed to validate the results of these early studies using a digital elevation model. We delineated the remnant surfaces of the basin by morphometric and GIS techniques. Then, based on field surveys and former geological maps; we characterised these remnant surfaces, and their area was measured as well. The results of this study contribute to a better understanding of the surface evolution of the basin and its surroundings.