Preprints
Filtering by Subject: Earth Sciences
Ge and Si isotope behavior during intense tropical weathering and ecosystem cycling
Published: 2020-01-03
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
Chemical weathering of volcanic rocks in warm and humid climates contributes disproportionately to global solute fluxes. Geochemical signatures of solutes and solids formed during this process can help quantify and reconstruct volcanic weathering intensity in the past. Here, we measured silicon (Si) and germanium (Ge) isotope ratios of the soils, clays, and fluids from a tropical lowland [...]
The Origin of Continental Carbonates in Andean Salars: A Multi-Tracer Geochemical Approach in Laguna Pastos Grandes (Bolivia)
Published: 2020-01-03
Subjects: Earth Sciences, Geochemistry, Hydrology, Physical Sciences and Mathematics
In continental volcanic settings, abundant carbonate precipitation can occur with atypical facies compared to marine settings. The (bio-)chemical processes responsible for their development and early diagenesis are typically complex and not fully understood. In the Bolivian Altiplano, Laguna Pastos Grandes hosts a 40-km2 carbonate platform with a great diversity of facies and provides an ideal [...]
Improved Accuracy of Watershed-Scale General Circulation Model Runoff Using Deep Neural Networks
Published: 2020-01-02
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Projecting impacts of climate change on water resources is a vital research task, and general circulation models (GCMs) are important tools for this work. However, the spatial resolution of downscaled GCMs makes them difficult to apply to non-grid conforming scales relevant to water resources management: individual watersheds. Machine learning techniques like deep neural networks (DNNs) may [...]
Landscape variables in the Indian (Peninsular) catchments: insights into hydro-geomorphic evolution
Published: 2020-01-02
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The river systems in peninsular India are remained unexplored in terms of hydro-geomorphic evolution, though a few works are carried out in order to understand the tectonic and structural evolution with paleoclimate. Morphometric analysis at catchment scale delivers insights into the dynamics, erosion capacity, probability of flood occurrence, lithological and structural control, and genetic [...]
Artificial and natural radionuclides in cryoconite as tracers of supraglacial dynamics
Published: 2020-01-02
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Cryoconite, a sediment found on the surface of glaciers, is known for its ability to accumulate radionuclides. New data on cryoconite from the Morteratsch glacier (Switzerland) are presented with the aim to shed light on the mechanisms that control the distribution of radioactivity in cryoconite. Among the many radionuclides detected in our samples, we have identified 108mAg, an artificial [...]
Global mean surface temperature and climate sensitivity of the EECO, PETM and latest Paleocene
Published: 2020-01-02
Subjects: Earth Sciences, Physical Sciences and Mathematics
Accurate estimates of past global mean surface temperature (GMST) help to contextualise future climate change and are required to estimate the sensitivity of the climate system to CO2 forcing during the geological record. GMST estimates from the latest Paleocene and early Eocene (~57 to 48 million years ago) span a wide range (~9 to 23°C higher than pre-industrial) and prevent an accurate [...]
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 [...]