Preprints
Filtering by Subject: Tectonics and Structure
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: 2017-10-25
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 [...]