Preprints
Filtering by Subject: Earth Sciences
Active deformation and Plio-Pleistocene fluvial reorganization of the western Kura Fold-Thrust Belt, Georgia: implications for the evolution of the Greater Caucasus mountains and seismic hazard
Published: 2019-12-31
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
Since the Plio-Pleistocene, southward migration of shortening in the eastern part of the Greater Caucasus (GC) into the Kura foreland basin has progressively formed the Kura-Fold Thrust belt (KFTB) and Alazani piggyback basin, which separates the KFTB from the GC. Previous work argued for an eastward propagation of the KFTB, implying that the western portion in Georgia is the oldest, but this [...]
Stochastic, empirically‐informed model of landscape dynamics and its application to deforestation scenarios
Published: 2019-12-26
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Land change including deforestation undermines the sustainability of the environment. Using data on 1992‐2015 pattern change in over 1.7 million meso‐scale landscapes worldwide we developed a stochastic model of long‐term landscape dynamics. The model suggests that observed heterogeneous landscapes are short‐lived stages in a transition between quasi‐stable homogeneous landscapes of different [...]
Seismic reflection data reveal the 3D structure of the newly discovered Exmouth Dyke Swarm, offshore NW Australia
Published: 2019-12-26
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Dyke swarms are common on Earth and other planetary bodies, comprising arrays of dykes that can extend laterally for 10’s to 1000’s of kilometres. The vast extent of such dyke swarms, and their presumed rapid emplacement, means they can significantly influence a variety of planetary processes, including continental break-up, crustal extension, resource accumulation, and volcanism. Determining the [...]
Glacial cooling and climate sensitivity revisited
Published: 2019-12-26
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The Last Glacial Maximum (LGM), one of the best-studied paleoclimatic intervals, offers a prime opportunity to investigate how the climate system responds to changes in greenhouse gases (GHGs) and the cryosphere. Previous work has sought to constrain the magnitude and pattern of glacial cooling from paleothermometers, but the uneven distribution of the proxies, as well as their uncertainties, has [...]
Back-propagating super-shear rupture in the 2016 Mw7.1 Romanche transform fault earthquake
Published: 2019-12-26
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
How an earthquake rupture propagates strongly influences potentially destructive ground shaking. Complex ruptures often involve slip along multiple faults, masking information on the frictional behaviour of fault zones. Geometrically smooth ocean transform fault plate boundaries offer a favourable environment to study fault dynamics, because strain is accommodated along a single, wide fault zone [...]
Fault-zone damage promotes pulse-like rupture and back-propagating fronts via quasi-static effects
Published: 2019-12-26
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Damage zones are ubiquitous components of faults that may affect earthquake rupture. Simulations show that pulse-like rupture can be induced by the dynamic effect of waves reflected by sharp fault zone boundaries. Here we show that pulses can appear in a highly damaged fault zone even in the absence of reflected waves. We use quasi-static scaling arguments and quasi-dynamic earthquake cycle [...]
Effects of aseismic ridge subduction on geochemistry of frontal arc magmas
Published: 2019-12-13
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
Aseismic ridge subduction is considered to exert major controls on volcanic activity, formation of porphyry Cu-Au deposits and the generation of juvenile Earth’s crust. Yet, there are almost no studies that have addressed in a systematic way the effects of this process on the geochemistry of arc magmas. Here we explore the role of the subducted aseismic Carnegie ridge on modulating frontal arc [...]
Scheduling of Twin Telescopes and the Impact on Troposphere and UT1 Estimation
Published: 2019-12-13
Subjects: Earth Sciences, Engineering, Other Earth Sciences, Physical Sciences and Mathematics
Recently, several VGOS twin telescopes in Europe were completed. We examine the use of VGOS twin telescopes by a new scheduling approach. This ap- proach is based on integer linear programming and cre- ates uniform distributed observations over time. Sev- eral VLBI intensive sessions are rescheduled involving the VGOS twin telescopes and the impact on the tropo- sphere and UT1 estimation is [...]
Fluid surface coverage showing the controls of rock mineralogy on the wetting state
Published: 2019-12-13
Subjects: Chemical Engineering, Earth Sciences, Engineering, Petroleum Engineering, Physical Sciences and Mathematics
The wetting state is an important control on flow in subsurface multi fluid phase systems, e.g., carbon storage and oil production. Advances in X-ray imaging allow us to characterise the wetting state using imagery of fluid arrangement within the pores of rocks. We derived a model from equilibrium thermodynamics relating fluid coverage of rock surfaces to wettability and fluid saturation. The [...]
Four-dimensional surface motions of the Slumgullion landslide and quantification of hydrometeorological forcing
Published: 2019-12-09
Subjects: Earth Sciences, Geomorphology, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics
Landslides modify the natural landscape and cause fatalities and property damage worldwide. Quantifying landslide dynamics is challenging due to the stochastic nature of the environment. With its large area of ~1 km2 and perennial motions at ~10-20 mm per day, the Slumgullion landslide in Colorado, USA, represents an ideal natural laboratory to better understand landslide behavior. Here, we use [...]
Open Access publishing practice in Geochemistry: current state and look to the future
Published: 2019-12-09
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
Open Access (OA) describes the free, unrestricted access to and re-use of research articles. Recently, a new wave of interest, debate, and practice surrounding OA publishing has emerged. In this paper, we provide a simple overview of the trends in OA practice in the broad field of geochemistry. Characteristics of the approach such as whether or not an article processing charge (APC) exists, what [...]
U-Th dating of lake sediments: Lessons from the 700 kyr sediment record of Lake Junín, Peru
Published: 2019-12-09
Subjects: Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology
*----- NOTE: This is a peer reviewed preprint of a paper accepted in Quaternary Science Reviews as of June 8, 2020 -----* Deep sediment cores from long-lived lake basins are fundamental records of paleoenvironmental history, but the power of these reconstructions has often been limited by poor age control. Uranium-thorium (U-Th) dating has the potential to fill a gap in current geochronological [...]
Ferruginous oceans during OAE1a and collapse of the marine sulfate pool
Published: 2019-12-06
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
Seawater sulfate is one of the largest oxidant pools at Earth’s surface today and its concentration in the oceans is generally assumed to have varied between 5 and 28 mM since the early Phanerozoic Eon. Intermittent and potentially global Oceanic Anoxic Events (OAEs) are accompanied by changes in seawater sulfate concentrations and signal perturbations in the Earth system associated with major [...]
The interplay between clay fabric and mechanical response of deep-seated landslides
Published: 2019-12-05
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geology, Geotechnical Engineering, Physical Sciences and Mathematics
Deep-seated landslides are amongst the most devastating natural hazards on earth, typically involving a rigid rock mass sliding over a weak, clayey shear-band. The mechanical response of this shear-band to the loading of the overburden is therefore critical for the stability of a landslide. We hereby show that this mechanical response is strongly linked to the mineralogy and microstructure of the [...]
Notes on the creation and manipulation of solid solution models
Published: 2019-12-04
Subjects: Chemistry, Earth Sciences, Materials Chemistry, Mineral Physics, Physical Sciences and Mathematics
A large class of solid solution models are built on the premise that exchange of chemical species takes place on a finite number of unique sites, and that the thermodynamic properties of the solution are a function of the proportions of species occupying each of the sites. The site-occupancy spaces spanned by such models are geometrically equivalent to convex polytopes, n-dimensional [...]