Preprints
Filtering by Subject: Geology
Pleistocene - Holocene volcanism at the Karkar geothermal prospect, Armenia
Published: 2020-01-22
Subjects: Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Volcanology
Quaternary volcanic centres north of the Bitlis-Zagros suture in Turkey, Iran and the Caucasus represent both volcanic hazards and potential or actual geothermal energy resources. Such challenges and opportunities cannot be fully quantified without understanding these volcanoes’ petrogenesis, geochronology and magmatic, tectonic or other eruption triggers. In this preliminary study, we discuss [...]
Discriminating stacked distributary channel from palaeovalley fill sand bodies in foreland basin settings
Published: 2020-01-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Stratigraphy
Stacked fluvial distributary channel deposits and palaeovalley fills can form major, multi-storey sand bodies with similar thicknesses, and with lateral extents often greater than a single exposure. Consequently, they can be difficult to tell apart from one another using outcrop data. This study addresses this problem by quantitatively analysing the architecture of five stacked fluvial [...]
The role of natural clays in the sustainability of landfill liners
Published: 2020-01-10
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Geochemistry, Geology, Geotechnical Engineering, Physical Sciences and Mathematics
Engineered synthetic liners on their own are not the ideal solution to protect land, water and living beings against landfill leachate pollution. Despite their impermeability, engineered liners are susceptible to fail during installation and after a few years of landfill operation, and have no attenuation properties. Conversely, natural clay liners can attenuate leachate pollutants by reactions [...]
Lessons learned from monitoring of turbidity currents and guidance for future platform designs
Published: 2020-01-09
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Turbidity currents transport globally significant volumes of sediment and organic carbon into the deep-sea and pose a hazard to critical infrastructure. Despite advances in technology, their powerful nature often damages expensive instruments placed in their path. These challenges mean that turbidity currents have only been measured in a few locations worldwide, in relatively shallow water depths [...]
The mixology of precursory strain partitioning approaching brittle failure in rocks
Published: 2020-01-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
We examine the strain accumulation and localization process throughout twelve triaxial compression experiments on six rock types deformed in an X-ray transparent apparatus. In each experiment, we acquire 50-100 tomograms of rock samples at differential stress steps during loading, revealing the evolving 3D distribution of X-ray absorption contrasts, indicative of density. Using digital volume [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
Abrupt Arctic Warming Repeatedly Led to Prolonged Drought and Glacial Retreat in the Tropical Andes During the Last Glacial Cycle
Published: 2019-12-03
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Sedimentology
A sediment core spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes reveals abrupt climatic events on a centennial-millennial time scale. These events, which involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake, occurred during the abrupt warmings recorded in [...]
Simulating Electropulse Fracture of Granitic Rock
Published: 2019-11-22
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geology, Geotechnical Engineering, Mining Engineering, Physical Sciences and Mathematics
Electropulse treatments employ a series of high-voltage discharges to break rock into small fragments. As these methods are particularly suited to fracturing hard brittle rocks, electropulse treatments can serve to enhance or substitute for more traditional mechanical approaches to drilling and processing of these materials. Nevertheless, while these treatments have the potential to improve [...]
Stratigraphic reservoir compartmentalization: causes, recognition, and implications for the geological storage of carbon dioxide
Published: 2019-11-22
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
The impact of carbon capture and storage (CCS) in mitigating anthropogenic emissions of greenhouse gases is potentially great, but its success is strongly dependent on identifying suitable geological storage sites. One of the key uncertainties in this regard is the degree of compartmentalization of the target storage horizon. Many studies have examined reservoir compartmentalization in oil and [...]
Revised timing of Cenozoic Atlantic incursions and changing hinterland sediment sources during southern Patagonian orogenesis
Published: 2019-11-21
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Stratigraphy
New detrital zircon U-Pb geochronology data from the Cenozoic Magallanes-Austral Basin in Argentina and Chile ~51°S establish a revised chronostratigraphy of Paleocene – Miocene foreland synorogenic strata and document the rise and subsequent isolation of hinterland sources in the Patagonian Andes from the continental margin. The upsection loss of zircons derived from the hinterland Paleozoic and [...]
Quantitatively deciphering paleostrain from digital outcrops model and its application in the eastern Tian Shan, China
Published: 2019-11-21
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
The knowledge of the strain/stress field evolution in time is fundamental to the understanding of the earth dynamic system. Based on the principle that past tectonic stress should have left traces in the rocks, geologists have been trying to determine the paleostress history from evidence found in rocks for decades. Recent development of techniques for automatic extraction of fracture surfaces [...]