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Geomorfologické projevy neotektonické aktivity podél úpatního zlomu pohoří Cordillera Blanca, Peru / Geomorphological evidence of neotectonic activity along Cordillera Blanca fault zone, PeruMasák, Ondřej January 2012 (has links)
Southwest base of Cordillera Blanca mts. in South American Ands belongs to the most tectonically active fault zones. The core of this thesis was making of a detailed geomorphological map based on remote sensing satellite images for the purpose of analysis of direct and indirect manifestations of neotectonics. The greatest emphasis was placed on morphological manifestations of tectonics movements which are fault scarps facets and vertical fault steps deforming other shapes of relief - e.g. lateral moraines, dejection cones. Vertical steps reach from a few meters to tens of meters (max. 60 m) according to the age of influenced landform. Evaluation of measurements from deformometr from locality Pitec shows main trends of movements - moderate rise of massif, slow opening of fault plane and negligible left-lateral slip. Calculation of mountain-front sinuosity index, whose values were found relatively low, confirms high tectonic activity of fault zone. Analysis of longitudinal stream profiles hasn't showed presence of knick-points in the place of crossing with fault zone. Non-continuous process of lifting movements, whose interval is estimated at 1ka to 3ka (while the very last 2ka has been in relative tectonic calm), could be a possible explanation. Deep erosion of water streams wiped the tectonics...
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Tectonomorphic and kinematic characterization of Neogene deformation in the southern Central Andes (23˚-28˚S, NW Argentina)Daxberger, Heidi 10 1900 (has links)
<p>This thesis focuses on the tectonomorphologic evolution of the Central Andean Puna Plateau and its eastern foreland. The collective findings of fault-slip and tectonomorphic analyes help in understanding the mechanical behavior of non-collisional orogens at convergent plate boundaries and result in an improved Neogene tectonic record of the Central Andes.</p> <p>Fault-slip analysis indicates Neogene WNW-ESE horizontal shortening of the thickened crust of the Puna Plateau and Eastern Cordillera and simultaneous lateral gravitational spreading. The less thickened of Pampean Ranges continue to undergo horizontal shortening only. The importance of N-S extension in the kinematics of elevated parts of the Central Andes is underscored by the strike-slip components on prominent dip-slip faults. Strain axis configurations in the southern Central Andes are generally controlled by (1) overall WNW-ESE horizontal shortening imposed by plate convergence and (2) differences in crustal thickness, i.e., gravitational potential energy. Therefore, a geodynamic interpretations in which still increasing elevation and crustal thickness significantly influence upper-crustal kinematics of the southern Central Andes is suggested.</p> <p>To allow regional-scale tectonomorphic studies, including Valley-Width-to-Valley-Height (Vf) ratio and the Transverse-Topographic-Symmetry (T-) factor, an Esri ArcGIS compatible software tool was developed. This Geographical Information System (GIS)-based tool, was coded in Python to enable conversion to other ArcGIS versions. This herein presented first version of the tool is fully functioning and drastically reduces the otherwise long processing times.</p> <p>A qualitative main basin symmetry description, Mountain-Front-Sinuosity (Smf) indices, and Vf-ratios of second-order drainage basins, indicate ubiquitous Quaternary deformation on reverse and thrust faults in the southern Central Andes. The recorded Quaternary deformation strongly influences Quaternary landform development, as shown by main drainage basin asymmetries and second-order drainage basins shapes. However, non-systematic T-factor distribution for second-order basins indicates that basin asymmetry is subject to litholigcal variations.</p> / Doctor of Philosophy (PhD)
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