Preprints
Filtering by Subject: Physical Sciences and Mathematics
Ice shelf rift propagation and the mechanics of wave-induced fracture
Published: 2017-11-28
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Distant storms, tsunamis, and earthquakes generate waves on floating ice shelves. Previous studies, however, have disagreed about whether the resulting wave-induced stresses may cause ice shelf rift propagation. Most ice shelf rifts show long periods of dormancy suggesting that they have low background stress concentrations and may therefore be susceptible to wave-induced stresses. Here, I [...]
Lithospheric flexure and rheology determined by climate cycle markers in the Corinth Rift
Published: 2017-11-28
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
Geomorphic strain markers accumulating the effects of many earthquake cycles help to constrain the mechanical behaviour of continental rift systems as well as the related seismic hazards. In the Corinth Rift (Greece), the unique record of onshore and offshore markers of Pleistocene ~100-ka climate cycles provides an outstanding possibility to constrain rift mechanics over a range of timescales. [...]
Sedimentology and reservoir properties of tabular and erosive offshore transition deposits in wave-dominated, shallow-marine strata: Book Cliffs, USA
Published: 2017-11-28
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
Facies models for wave-dominated shorelines include an "offshore transition zone" between shelfal mudstones and nearshore shoreface sandstones. Offshore transition zone deposits are commonly tabular sandstone beds interbedded with continuous mudstone beds. However, observations from the Blackhawk Formation show that the offshore transition zone locally consists of erosive-based sandstone beds [...]
How, where and when do radial faults grow near salt diapirs?
Published: 2017-11-27
Subjects: Earth Sciences, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
We examine 3-D seismic reflection data from the Santos Basin, offshore Brazil to determine how, where and when do radial faults grow near a sub-circular salt diapir (stock). We show roof stretching alone cannot account for the large heights and lengths of the kilometre-scale radial faults, suggesting stock widening (‘stem push’), a mechanism implied in numerical models but not yet documented in [...]
The evolution of REE mineralisation within the Ditrău Alkaline Complex, Romania: interplay of magmatic and hydrothermal processes
Published: 2017-11-27
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
The Ditrău Igneous Complex (NE Romania) is a tilted Mesozoic layered alkaline intrusion (~19 km diameter), with enrichments in rare earth elements (REE), niobium, tantalum and molybdenum. It has the potential to contribute to a secure and sustainable European REE mining industry, ensuring supply security for these critical metals. The complex comprises layered ultramafic rocks, alkali gabbros, [...]
The role of coseismic Coulomb stress changes in shaping the hard-link between normal fault segments
Published: 2017-11-27
Subjects: Earth Sciences, Geology, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The mechanism and evolution of fault linkage is important in the growth and development of large faults. Here we investigate the role of coseismic stress changes in shaping the hard-links between parallel normal fault segments (or faults), by comparing numerical models of the Coulomb stress change from simulated earthquakes on two en echelon fault segments to natural observations of hard-linked [...]
Rupture Process during the Mw 8.1 2017 Chiapas Mexico Earthquake: Shallow Intraplate Normal Faulting by Slab Bending
Published: 2017-11-25
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
A seismic source model for the Mw 8.1 2017 Chiapas, Mexico, earthquake was constructed by kinematic waveform inversion using globally observed teleseismic waveforms, suggesting that the earthquake was a normal-faulting event on a steeply dipping plane, with the major slip concentrated around a relatively shallow depth of 28 km. The modeled rupture evolution showed unilateral, down-dip propagation [...]
Throw Rate Variability on Gravity-Driven Normal Faults; Constraints from the Gudrun Fault, South Viking Graben, Offshore Norway
Published: 2017-11-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The growth and throw rate variability on normal faults can reflect fault interaction, plate tectonic forces and, in gravity-driven systems, variations in sediment loading. Because earthquakes may occur as faults slip, it is important to understand what processes influence throw rate variability on normal faults to be able to predict seismic hazards in extensional terranes. Furthermore, the rate [...]
Temperatures recorded by cosmogenic noble gases since the last glacial maximum in the Maritime Alps
Published: 2017-11-24
Subjects: Earth Sciences, Geochemistry, Geomorphology, Glaciology, Other Earth Sciences, Physical Sciences and Mathematics
While proxy records have been used to reconstruct late Quaternary climate parameters throughout the European Alps, our knowledge of deglacial climate conditions in the Maritime Alps is limited. Here, we report temperatures recorded by a new and independent geochemical technique—cosmogenic noble gas paleothermometry—in the Maritime Alps since the last glacial maximum. We measured cosmogenic 3He in [...]
The INTAV intercomparison of electron-beam microanalysis of glass by tephrochronology laboratories, results and recommendation
Published: 2017-11-23
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
The INternational focus group on Tephrochronology And Volcanism (INTAV) of the International Union for Quaternary Research (INQUA) has conducted an intercomparison of tephrochronology laboratories with electron-beam microanalytical data on volcanic glasses submitted from 27 instruments at 24 institutions in 9 countries. This assessment includes most active tephrochronology laboratories and [...]
Temporal evolution of extensional fault-propagation folds
Published: 2017-11-23
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure
Integration of three-dimensional seismic and well data from the Upper Jurassic North Sea rift provides insights into the temporal evolution of fault-propagation folds in extensional settings. The hangingwall of the Oseberg fault zone is characterised by an asymmetric, fault-parallel syncline interpreted as the hangingwall portion of a breached monocline which formed in response to an [...]
BIOMEDIATION OF SEDIMENT GRAVITY FLOW DYNAMICS
Published: 2017-11-22
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Sediment gravity flows (SGFs) are the primary process by which sediment and organic carbon are transported from the continental margin to the deep ocean. Forty percent of the total marine organic carbon pool is represented by cohesive extracellular polymeric substances (EPS) produced by marine benthic and pelagic micro-organisms. EPS research to date has focussed on coastal environments, where [...]
Comparison of 0-D, 1-D and 2-D model capabilities for tidal range energy resource assessments
Published: 2017-11-22
Subjects: Civil and Environmental Engineering, Computational Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Hydraulic Engineering, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Power and Energy
Tidal range energy projects present an attractive means for the predictable and large-scale generation of electricity from the marine environment. In particular, proposals are under consideration in UK waters, with their feasibility currently being under high levels of scrutiny. This is due to a combination of potential environmental and socio-economic impacts that are challenging to quantify in [...]
Numerical solution of a non-linear conservation law applicable to the interior dynamics of partially molten planets
Published: 2017-11-21
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Fluid Dynamics, Geophysics and Seismology, Numerical Analysis and Computation, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics, Physics
The energy balance of a partially molten rocky planet can be expressed as a non-linear diffusion equation using mixing length theory to quantify heat transport by both convection and mixing of the melt and solid phases. Crucially, in this formulation the effective or eddy diffusivity depends on the entropy gradient, dS/dr, as well as entropy itself. First we present a simplified model with [...]
High curvatures drive river meandering
Published: 2017-11-20
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics
One of the long- and widely held ideas about the dynamics of meandering rivers is that migration slows down in bends with higher curvatures. Identifying the radius of curvature at which migration is fastest is standard practice in field studies of meandering rivers. High-resolution measurements of local migration rates in time-lapse Landsat images from two rapidly migrating rivers in the Amazon [...]