Preprints
Filtering by Subject: Tectonics and Structure
Quantificação da Deformação Finita nos Metagranitoides Cariris Velhos na Região de Alagoa Grande (PB)
Published: 2017-10-31
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The Cariris Velhos Metagranitoids are considered an important geological unit of the Transversal Zone (Borborema Province – NE Brazil). We evaluated the use of raw and processed digital images to obtain the deformation ellipsoid for the Cariris Velhos Metagranitoids using the Inertia Tensor and Intercepts methods. The ellipsoid symmetry of the deformed fabric was very similar for both methods, [...]
SRTM resample with short distance-low nugget kriging
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure
The Shuttle Radar Topography Mission (SRTM), was flow on Space Shuttle Endeavour in February 2000, with the objective of acquire a digital elevation model of all land between 60º north latitude and 56º south latitude, using Interferometric Synthetic Aperture Radar (InSAR) techniques. SRTM data is distributed at horizontal resolution of 1 arc-second (aprox. 30m) for areas within the USA and at 3 [...]
SRTM-based morphotectonic analysis of the Poços de Caldas Alkaline Massif, southeastern Brazil
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure
An evaluation of SRTM 03” data applicability in geomorphology and morphotectonics analysis is proposed, considering the morphometric parameters slope, aspect, surface roughness and isobase surface. The study area, in southeastern Brazil, comprises the Poços de Caldas Alkaline Massif, a 33km-diameter Late Cretaceous collapsed volcanic caldera. Morphometric indices evaluated showed the correlation [...]
Trend-surfaces analysis of morphometric parameters: A case-study in southearstern Brazil
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure
Trend-surface analysis was carried out on data from morphometric parameters isobase and hydraulic gradient. The study area, located in the eastern border of Quadrilátero Ferrífero, southeastern Brazil, presents four main geomorphological units, one characterized by fluvial dissection, two of mountainous relief, with a scarp of hundreds of meters of fall between them, and a flat plateau in the [...]
Morphometric analysis in Geographic Information Systems: applications of free software GRASS and R
Published: 2017-10-31
Subjects: Earth Sciences, Geographic Information Sciences, Geography, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science, Tectonics and Structure
Development and interpretation of morphometric maps are important tools in studies related to neotectonics and geomorphology; Geographic Information Systems (GIS) allows speed and precision to this process, but applied methodology will vary according to available tools and degree of knowledge of each researcher about involved software. A methodology to integrate GIS and statistics in morphometric [...]
Normal fault growth in layered basaltic rocks: the role of strain rate in fault evolution
Published: 2017-10-30
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Conceptual models for the evolution of dilatant faults in volcanic rift settings involve a step-wise growth pattern, involving upward propagation of subsurface faults, surface monocline formation, which are breached by subvertical, open faults. Immature, discontinuous normal faults are considered representative of the early stages of mature, linked faults that accommodate extensional strains. We [...]
Igneous sills record far-field and near-field stress interactions during volcano construction: Isle of Mull, Scotland
Published: 2017-10-28
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Sill emplacement is typically associated with horizontally mechanically layered host rocks in a near-hydrostatic far-field stress state, where contrasting mechanical properties across the layers promote transitions from dykes, or inclined sheets, to sills. We used detailed field observations from the Loch Scridain Sill Complex (Isle of Mull, UK), and mechanical models to show that layering is not [...]
Influence of fault reactivation during multiphase rifting: the Oseberg area, Northern North Sea rift
Published: 2017-10-28
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Multiphase rifts tend to produce fault populations that evolve by the formation of new faults and reactivation of earlier faults. The resulting fault patterns tend to be complex and difficult to decipher. In this work we use seismic reflection data to examine the evolution of a normal fault network in the Oseberg Fault Block in the northern North Sea Rift System – a rift system that experienced [...]
Pre-existing normal faults have limited control on the rift geometry of the northern North Sea
Published: 2017-10-28
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Many rifts develop in response to multiphase extension with numerical and physical models suggesting that reactivation of first-phase normal faults and rift-related variations in bulk crustal rheology control the evolution and final geometry of subsequent rifts. However, many natural multiphase rifts are deeply buried and thus poorly exposed in the field and poorly imaged in seismic reflection [...]
Balancing sub- and supra-salt strain in salt-influenced rifts: Implications for extension estimates
Published: 2017-10-28
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The structural style of salt-influenced rifts may differ from those formed in predominantly brittle crust. Salt can decouple sub- and supra-salt strain, causing sub-salt faults to be geometrically decoupled from, but kinematically coupled to and responsible for, supra-salt forced folding. Salt-influenced rifts thus contain more folds than their brittle counterparts, an observation often ignored [...]
Thermo-mechanical numerical model of the transition from continental rifting to oceanic spreading: the case study of the Alpine Tethys
Published: 2017-10-26
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
We develop a two-dimensional thermo-mechanical numerical model in which the formation of oceanic crust and serpentinite due to the hydration of the uprising mantle peridotite has been implemented, with the aim of discussing the behavior of the lithosphere of the Alps and Northern Apennines during the transition from continental rifting to ocean spreading of the Alpine Tethys. The predictions of [...]
Morphological expressions of crater infill collapse: model simulations of Chaotic Terrains on Mars
Published: 2017-10-26
Subjects: Earth Sciences, Geology, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Martian chaotic terrains are characterized by deeply depressed intensively fractured areas that contain a large number of low-strain tilted blocks. Stronger deformation (e.g. higher number of fractures) is generally observed in the rims when compared to the middle regions of the terrains. The distribution and number of fractures and tilted blocks are correlated with the size of the chaotic [...]
2-D numerical study of hydrated wedge dynamics from subduction to post-collisional phases
Published: 2017-10-26
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
We developed a 2-D finite element model to investigate the effect of shear heating and mantle hydration on the dynamics of the mantle wedge area. The model considers an initial phase of active oceanic subduction, which is followed by a post-collisional phase characterized by pure gravitational evolution. To investigate the impact of the subduction velocity on the thermomechanics of the system, [...]
Rift zone-parallel extension during segmented fault growth: application to the evolution of the NE Atlantic
Published: 2017-10-26
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The mechanical interaction of propagating normal faults is known to influence the linkage geometry of first-order faults, and the development of second-order faults and fractures, which transfer displacement within relay zones. Here we use natural examples of growth faults from two active volcanic rift zones (Koaʻe, Island of Hawaiʻi and Krafla, northern Iceland) to illustrate the importance of [...]