Preprints
There are 4725 Preprints listed.
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 [...]
Stronger Atlantic hurricanes: Validating Elsner et al. (2008)
Published: 2019-12-04
Subjects: Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Using satellite derived wind speed estimates from tropical cyclones over the 25-year period 1981--2006, Elsner et al. (2008) showed the strongest tropical cyclones getting stronger. They related the increasing intensity to rising ocean temperatures consistent with theory. Oceans continued to warm since that paper was published so the intensity of the strongest cyclones should have continued [...]
Estimation of surface and deep flows from sparse SSH observations of geostrophic ocean turbulence using Deep Learning
Published: 2019-12-04
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Satellite altimeters provide global observations of sea surface height (SSH) and present a unique dataset for advancing our theoretical understanding of upper ocean dynamics and monitoring its variability. Considering that mesoscale SSH patterns of 50--300 km in size can evolve on timescales comparable to or shorter than satellite return periods, it is challenging to accurately reconstruct the [...]
A machine learning approach to tungsten prospectivity modelling using knowledge-driven feature extraction and model confidence
Published: 2019-12-04
Subjects: Earth Sciences, Geology, Other Earth Sciences, Physical Sciences and Mathematics
Novel mineral prospectivity modelling presented here applies knowledge-driven feature extraction to a data-driven machine learning approach for tungsten mineralisation. The method emphasises the importance of appropriate model evaluation and develops a new Confidence Metric to generate spatially refined and robust exploration targets. The data-driven Random Forest™ algorithm is employed to model [...]
An interpreted language implementation of the Vaganov-Shashkin tree-ring proxy system model
Published: 2019-12-04
Subjects: Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
We describe the implementation of the Vaganov-Shashkin tree-ring growth model (VSM) in MATLAB. VSM, originally written in Fortran, mimics subdaily and daily resolution processes of cambial growth as a function of soil moisture, air temperature, and insolation, with environmental forcing modeled as the principle of limiting factors. The re-implementation in a high level interpreted language, [...]
Evaluation and comparison of a machine learning cloud identification algorithm for the SLSTR in polar regions
Published: 2019-12-04
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
A Feed Forward Neural Net (NN) approach to distinguish between clouds and the surface has been applied to the Sea and Land Surface Temperature Radiometer in polar regions. The masking algorithm covers the Arctic, Antarctic and regions typically classified as the cryosphere such as northern hemisphere permafrost. The mask has been trained using collocations with the CALIOP active lidar, which in [...]
Climate driven Holocene erosion in central Ukraine
Published: 2019-12-04
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The younger Quaternary erosion history was reconstructed in a catchment close to the Chalcolithic giant settlement Maidanetske, central Ukraine based on dated sediment sequences. Four trenches and a long percussion drill-core were analyzed in a valley grading from a Loess covered plateau towards the Talianky River. The sediments were dated via a combination of radiocarbon dating, optical [...]
Scaling Laws for Regional Stratification at the top of Earth’s Core
Published: 2019-12-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Seismic and geomagnetic observations have been used to argue both for and against a global stratified layer at the top of Earth’s outer core. Recently, we used numerical models of turbulent thermal convection to show that imposed lateral variations in core-mantle boundary (CMB) heat flow can give rise to regional lenses of stratified fluid at the top of the core while the bulk of the core remains [...]
Advanced ML and AI Approaches for Proxy-based Optimization of CO2-Enhanced Oil Recovery in Heterogeneous Clastic Reservoirs
Published: 2019-12-04
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Design of Experiments and Sample Surveys, Earth Sciences, Multivariate Analysis, Other Earth Sciences, Physical Sciences and Mathematics, Programming Languages and Compilers, Statistics and Probability
Constructing a simpler model to represent a complex reservoir simulation that will be employed to define the optimum future development plans have been achieved through the use of different simulation techniques that include EOS-compositional reservoir simulation, Proxy Modeling as well as Design of Experiments. Once reliable history matching was achieved, the key five operational decision [...]
Quantifying Computational Efficiency of Adaptive Mesh Refinement for Shallow Water Solvers
Published: 2019-12-04
Subjects: Computer Sciences, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics
Non-uniform, dynamically adaptive meshes are a useful tool for reducing computational complexities for geophysical simulations that exhibit strongly localised features such as is the case for example for tsunami, hurricane or typhoon prediction. Theoretical insight for mesh-based numerical methods, however, is largely restricted to uniform meshes as they allow for a traditional definition of [...]
Spatiotemporal correlation analysis of noise-derived seismic body waves with ocean wave climate and microseism sources
Published: 2019-12-04
Subjects: Earth Sciences, Geophysics and Seismology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Seismic signals can be extracted from ambient noise wavefields by the correlation technique. Recently, a prominent P‐type phase was observed from teleseismic noise correlations in the secondary microseism period band. The phase is named Pdmc in this paper, corresponding to its origin from the interference between the direct P waves transmitting through the deep mantle and the core (P and PKPab [...]
Dreibrodt et al.- Holocene erosion history in central Ukraine
Published: 2019-12-04
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The younger Quaternary erosion history was reconstructed in a catchment close to the Chalcolithic giant settlement Maidanetske, central Ukraine based on dated sediment sequences. Four trenches and a long percussion drill-core were analyzed in a valley grading from a Loess covered plateau towards the Talianky River. The sediments were dated via a combination of radiocarbon dating, optical [...]