Preprints
Filtering by Subject: Tectonics and Structure
The variation and visualisation of elastic anisotropy in rock-forming minerals
Published: 2019-10-31
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Tectonics and Structure
All minerals behave elastically, a rheological property that controls their ability to support stress, strain and pressure, the nature of acoustic wave propagation and influences subsequent plastic (i.e. permanent, non-reversible) deformation. All minerals are intrinsically anisotropic in their elastic properties – that is, they have directional variations that are related to the configuration [...]
Surface faulting earthquake clustering controlled by fault and shear-zone interactions
Published: 2019-10-25
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Surface faulting earthquakes are known to cluster in time, from historical and palaeoseismic studies, but the mechanism(s) responsible for clustering, such as fault interaction, strain-storage, and evolving dynamic topography, are poorly quantified, and hence not well understood. We present a quantified replication of observed earthquake clustering in central Italy. Six active normal faults are [...]
Inheritance of penetrative basement anisotropies by extension-oblique faults: Insights from analogue experiments
Published: 2019-10-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
During rifting, pre-existing penetrative basement fabrics can affect new faults in cover rocks by a mechanism that does not appear to involve reactivation. This subtle form of inheritance can significantly impact fault network architecture in rift basins above laterally variable basement domains with geomechanical anisotropies. Here we use multi-layer, brittle-ductile, crustal-scale analogue [...]
Dynamic fault parameters preprint
Published: 2019-10-24
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The behavior of faults under dynamic loading reflects the response of the shape and composition of the fault to the applied mechanical loading and environmental conditions. The interaction between the fault properties and the loading system is controlled by multiple variables that may generate an inherently complex behavior. The usage of multi-parametric variables can illuminate the controlling [...]
Distributed normal faulting in the tip zone of the South Alkyonides Fault System, Gulf of Corinth, constrained using 36Cl exposure dating of Late-Quaternary wave-cut platforms.
Published: 2019-10-24
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
In order to investigate the geometry, rates and kinematics of active faulting in the region close to the tip of a major crustal-scale normal fault in the Gulf of Corinth, Greece, we have mapped faults and dated their offsets using a combination of 234U/230Th coral dates and in situ 36Cl cosmogenic exposure ages for sediments and wave-cut platforms deformed by the faults. Our results show that [...]
Pre-breakup extension in the northern North Sea defined by complex strain partitioning and heterogeneous extension rates
Published: 2019-10-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The early stages of continental rifting are accommodated by the growth of upper-crustal normal fault systems that are distributed relatively evenly across the rift width. Numerous fault systems define fault arrays, the kinematics of which are poorly understood due to a lack of regional studies drawing on high-quality subsurface data. Here we investigate the long-term (~150 Myr) growth of a [...]
Rotation, narrowing, and preferential reactivation of brittle structures during oblique rifting
Published: 2019-10-24
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Occurrence of multiple faults populations with contrasting orientations in oblique continental rifts and passive margins has long sparked debate about relative timing of deformation events and tectonic interpretations. Here, we use high-resolution three-dimensional thermo-mechanical numerical modeling to characterize the evolution of the structural style associated with varying geometries of [...]
Rock strength and structural controls on fluvial erodibility: implications for drainage divide mobility in a collisional mountain belt
Published: 2019-10-13
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
Numerical model simulations and experiments have suggested that when migration of the main drainage divide occurs in a mountain belt, it can lead to the rearrangement of river catchments, rejuvenation of topography, and changes in erosion rates and sediment flux. We assess the progressive mobility of the drainage divide in three lithologically and structurally distinct groups of bedrock in the [...]
“Conjugate margins” – An oversimplification of the complex southern North Atlantic rift and spreading system?
Published: 2019-10-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The prevalence of conjugate margin terminology and studies in the scientific literature is testimony to the contribution that this concept and approach has made to the study of passive margins, and more broadly extensional tectonics. However, when applied to the complex rift, transform and spreading system of the southern North Atlantic (i.e. the passive margins of Newfoundland, Labrador, [...]
Making mountains on Earth and beyond
Published: 2019-10-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Many of Earth’s mountains are formed in orogenic belts aligned along plate margins. Their altitudes (reaching >8,000 m above sea level in the Himalayas) are the result of the balance between tectonic forces causing their uplift and erosive processes causing their destruction. The tectonic forces result, in part, from isostacy which is determined by the plasticity of the asthenosphere, but [...]
Four-dimensional Variability of Composite Halokinetic Sequences
Published: 2019-10-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The architecture of salt diapir-flank strata (i.e. halokinetic sequences) is controlled by the interplay between volumetric diapiric flux and sediment accumulation rate. Halokinetic sequences consist of unconformity-bounded packages of thinned and folded strata formed by drape-folding around passive diapirs. These sequences are described by two end-members: (i) hooks, which are characterized by [...]
Crack to pulse transition and magnitude statistics during earthquake cycles on a self-similar rough fault
Published: 2019-10-08
Subjects: Earth Sciences, Engineering, Geophysics and Seismology, Mechanical Engineering, Physical Sciences and Mathematics, Tectonics and Structure, Tribology
Faults in nature demonstrate fluctuations from planarity at most length scales that are relevant for earthquake dynamics. These fluctuations may influence all stages of the seismic cycle; earthquake nucleation, propagation, arrest, and inter-seismic behavior. Here I show quasi-dynamic plane-strain simulations of earthquake cycles on a self-similar and finite 10 km long rough fault with [...]
Grain-scale deformation mechanisms and evolution of porosity in experimentally deformed Boom Clay
Published: 2019-10-03
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Boom Clay is a soft, slightly overconsolidated, uncemented claystone considered as potential host material for a radioactive waste repository in Belgium. We studied the evolution of microfabrics in samples which were shortened to 20% bulk strain in consolidated-undrained (CU) triaxial experiments at effective confining pressures of 0.375, 0.750 and 1.5 MPa, respectively. Results show a [...]
Key controls on hydrocarbon retention and leakage from structural traps in the Hammerfest Basin, SW Barents Sea: implications for prospect analysis and risk assessment
Published: 2019-10-03
Subjects: Analysis, Earth Sciences, Geology, Geophysics and Seismology, Mathematics, Physical Sciences and Mathematics, Tectonics and Structure
Evidence of hydrocarbon leakage has been well documented across the SW Barents Sea and is commonly associated with exhumation in the Cenozoic. However, further study is required to understand what specific mechanism(s) facilitate such leakage, and why this occurs in some locations and not others. We use seismic and well data to quantify fault- and top-seal strength based on mechanical and [...]
Holocene relative sea-level changes and glacial isostatic adjustment of the U.S. Atlantic coast
Published: 2019-09-30
Subjects: Climate, Earth Sciences, Environmental Sciences, Geomorphology, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
The first quality-controlled Holocene sea-level database for the U.S. Atlantic coast has been constructed from 686 sea-level indicators. The database documents a decreasing rate of relative sea-level (RSL) rise through time with no evidence of sea level being above present in the middle to late Holocene. The highest rates of RSL rise are found in the mid-Atlantic region. We employ the database to [...]