Preprints
Filtering by Subject: Geology
Influence of nodular structures on fracture development in fine-grained rocks: numerical simulations based on the discrete element method
Published: 2019-05-11
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Discrete element experiments were performed to simulate fracturing processes in nodule-bearing, fine-grained rocks. Two models that contain a collection of bonded circular particles were subjected to uniaxial compression to yield shortening and fracturing of the particle assembly. Model I with soft nodules produced incremental amount of microfractures within nodules during the early stage of [...]
Global distribution of sediment-hosted metals controlled by craton edge stability
Published: 2019-05-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Sustainable development and the transition to a clean-energy economy drives ever-increasing demand for base metals, significantly outstripping the discovery rate of new deposits and necessitating dramatic improvements in exploration success. Rifting of the continents has formed widespread sedimentary basins, some of which contain large quantities of copper, lead and zinc. Despite over a century [...]
Identification and Characterization of a Buried Volcanic Field Using Seismic Reflection and Borehole Data
Published: 2019-05-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Buried volcanoes occur in great numbers within sedimentary basins globally. Knowledge of ancient buried volcanic systems has improved significantly over the past two decades. The in-depth understanding of these buried systems was mainly possible due to increasing availability of high-quality seismic reflection and sub-surface borehole data. This paper examines a cluster of Miocene volcanoes now [...]
Paleogeographic and Morphologic Reconstroction of a Buried Monogenetic Volcanic Field
Published: 2019-05-07
Subjects: Earth Sciences, Geology, Life Sciences, Physical Sciences and Mathematics
Technological advances of our modern society motivated an unprecedented necessity to find natural resources in the subsurface of our planet. The search for these valuable resources has revealed an unexpected number of ancient volcanoes buried and preserved within sedimentary basins globally. Continuous improvements in remote sensing techniques such as seismic reflection can provide a valid [...]
Pre-existing intra-basement shear zones influence growth and geometry of non-colinear normal faults, western Utsira High–Heimdal Terrace, North Sea
Published: 2019-05-06
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Pre-existing intra-basement shear zones can induce mechanical and rheological heterogeneities that may influence rifting and the overall geometry of rift-related normal faults. However, the extent to which physical and kinematic interaction between pre-existing shear zones and younger rift faults control the growth of normal faults is less-well understood. Using 3D reflection seismic data from [...]
Microstructural Constraints on Magmatic Mushes under Kīlauea Volcano, Hawaiʻi
Published: 2019-05-06
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Physical Sciences and Mathematics, Volcanology
Distorted olivines of enigmatic origin are ubiquitous in erupted products from a wide range of volcanic systems (e.g., Hawaiʻi, Iceland, Andes). Investigation of these features at Kīlauea Volcano, Hawai’i, using an integrative crystallographic and chemical approach places quantitative constraints on mush pile thicknesses. Electron back-scatter diffraction (EBSD) reveals that the microstructural [...]
Terrestrial environmental change across the onset of the PETM and the associated impact on biomarker proxies: a cautionary tale
Published: 2019-04-29
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
The Paleocene-Eocene Thermal Maximum (PETM; ~ 56 million years ago (Ma) is the most severe carbon cycle perturbation event of the Cenozoic. Although the PETM is associated with warming in both the surface (~up to 8°C) and deep ocean (~up to 5°C), there are relatively few terrestrial temperature estimates from the onset of this interval. The associated response of the hydrological cycle during the [...]
A long-term, high-latitude record of Eocene hydrological change in the Greenland region
Published: 2019-04-26
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
A range of proxy approaches have been used to reconstruct short-term changes to Earth’s hydrological cycle during the early Eocene hyperthermals. However, little is known about the response of Earth’s hydrological and biogeochemical systems to long-term Cenozoic cooling, which began following the Early Eocene Climatic Optimum (53.3 – 49.4 million years ago; Ma). Here, we use the molecular [...]
Stratigraphy of Architectural Elements of a Buried Monogenetic Volcanic System and Implications for Geoenergy Exploration
Published: 2019-04-26
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Large volumes of magma emplaced and deposited within sedimentary basins can have an impact on their architectural style and geological evolution. Over the last decade, continuous improvement in techniques such as seismic volcano-stratigraphy and 3D seismic visualization of igneous rocks buried in sedimentary basins has helped increase knowledge about these “volcanic basins”. Here, we unravel the [...]
Application of multivariate statistical methods to hydrogeological property parameterisation from geotechnical and geophysical data
Published: 2019-04-26
Subjects: Earth Sciences, Environmental Sciences, Geology, Hydrology, Other Earth Sciences, Physical Sciences and Mathematics, Water Resource Management
Hydrogeological data sets are often relatively sparse compared to the scale of investigation, resulting in degrees of uncertainty which, although constrained, may be considered as not acceptable for achieving the desired precision in numerical modelling. The potential use of multivariate statistical methods in identifying correlations between geotechnical properties of the rock mass and hydraulic [...]
High-angular resolution electron backscatter diffraction as a new tool for mapping lattice distortion in geological minerals
Published: 2019-04-19
Subjects: Earth Sciences, Geology, Mineral Physics, Physical Sciences and Mathematics
Analysis of distortions of the crystal lattice within individual mineral grains is central to the investigation of microscale processes that control and record tectonic events. These distortions are generally combinations of lattice rotations and elastic strains, but a lack of suitable observational techniques has prevented these components being mapped simultaneously and routinely in earth [...]
The stratigraphic evolution of onlap in siliciclastic deep-water systems: Autogenic modulation of allogenic signals
Published: 2019-04-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Seafloor topography affects the sediment gravity flows that interact with it. Understanding this interaction is critical for accurate predictions of sediment distribution, paleogeography, and structural reconstructions of deep-water basins. The effects of seafloor topography can be seen from the bed scale, through facies transitions toward intra-basinal slopes, to the basin scale, where onlap [...]
Characterising strong force networks produced during granular shear using percolation methods: Revealing the bridge between local grain scale processes and macroscopic sliding
Published: 2019-04-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure
Faults, landslides and subglacial till often contain accumulations of granular debris. Their macroscopic motion is at least to some extent determined by the processes operating in this sheared granular material. A valid question in these environments is how the local behaviour at the individual granular contacts actually sums up to influence macroscopic sliding. Laboratory experiments and [...]
Determining cooling rates from mica 40Ar/39Ar thermochronology data: effect of cooling path shape
Published: 2019-04-02
Subjects: Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Physical Sciences and Mathematics
Tectonic models are commonly underpinned by metamorphic cooling rates derived from diffusive-loss thermochronology data. Such cooling ages are usually linked to temperature via Dodson’s 1973 closure temperature (TC) formulation, which specifies a 1/time-shaped cooling path. Geologists, however, commonly discuss cooling rates as a linear temperature/time shape. We present the results of a series [...]
The Cyclic Preservation of Clastic and Evaporitic Sabkha Sediments: Insights from the Cedar Mesa Sandstone Formation of the Cutler Group, Utah, USA
Published: 2019-04-01
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
The strata of arid continental basins commonly comprise evaporitic sediments deposited in sabkha settings combined with clastic sediments derived from aeolian, fluvial and/or lacustrine settings. The sedimentary character of these mixed successions and the degree to which evaporitic strata influence their composition, both contribute towards the economic potential of the evaporitic and the [...]