Preprints
Filtering by Subject: Geology
Progradational Slope Architecture and Sediment Partitioning in the Outcropping Mixed Siliciclastic-Carbonate Bone Spring Formation, Permian Basin, west Texas
Published: 2019-08-15
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Sediment transport and partitioning are important for understanding slope-building processes in mixed carbonate-siliciclastic sediment routing systems. The Permian-aged Bone Spring Formation, Delaware Basin, west Texas is a mixed carbonate-siliciclastic system that has been extensively studied in its basinal extent, but poorly constrained at its proximal, upper slope segment. In this study, we [...]
Scale matters: The influence of structural inheritance on fracture patterns
Published: 2019-08-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Fracture systems are often geometrically invariant across a range of scales, but the impact of structural inheritance on this relationship is poorly understood. This paper shows how fracture orientations in sedimentary rocks vary at different scales when influenced by pre-rift basement structures. We use high-resolution unmanned aerial vehicle (UAV) orthophotos to map folds and fractures in the [...]
Mass-transport complexes (MTCs) document minibasin subsidence patterns and diapir evolution in the northern Gulf of Mexico
Published: 2019-08-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Social and Behavioral Sciences
Mass-transport complexes (MTCs) dominate many salt-influenced sedimentary basins. Commonly in such settings, halokinesis is invoked as the primarily trigger for MTC emplacement. Despite being very well-imaged in seismic reflection data, we know little of how MTCs vary in terms of their sedimentological character, which may relate to their provenance, or their triggers. We use high-quality 3D [...]
Deep-water reservoir distribution on a salt-influenced slope, Santos Basin, offshore Brazil
Published: 2019-08-08
Subjects: Earth Sciences, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
Studies of near-seabed datasets show that salt tectonics controls the distribution and architecture of deep-water reservoirs in many salt-influenced basins. It is typically difficult, however, to study the distribution and stratigraphic evolution of depositional systems preserved at deeper, economically significant depths, reflecting poor seismic imaging of steeply dipping strata flanking [...]
A mechanistic erosion model for cosmogenic nuclide inheritance in fluvial single-clast exposure ages
Published: 2019-08-07
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Statistics and Probability, Tectonics and Structure
Terrestrial cosmogenic nuclides (TCNs), produced by the bombardment of Earth’s surface by cosmic rays, are widely used for age-dating and pacing surface processes. Sediments carry an inherited TCN concentration, useful for quantifying erosion and transport rates, but that must be subtracted when age-dating sedimentary landforms, such as alluvial fans. Here we present a mechanistic model of [...]
The Byers Basin: Jurassic-Cretaceous tectonic and depositional evolution of the forearc deposits of the South Shetland Islands and its implications for the northern Antarctic Peninsula
Published: 2019-08-01
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
This paper addresses the Jurassic–Cretaceous stratigraphic evolution of fore-arc deposits exposed along the west coast of the northern Antarctic Peninsula. In the South Shetland Islands, Upper Jurassic deep-marine sediments are uncomformably overlain by a Lower Cretaceous volcaniclastic sequence that crops out on Livingston, Snow and Low islands. U-Pb zircon ages are presented for the upper [...]
The Gondwanan margin in West Antarctica: insights from Late Triassic magmatism of the Antarctic Peninsula
Published: 2019-08-01
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Triassic orthogneisses of the Antarctic Peninsula provide evidence for the Palaeozoic and Mesozoic geological evolution of southern Gondwana within Pangaea. These rocks are sporadically exposed in southeastern Graham Land and northwestern Palmer Land, although reliable geochronological, geochemical and isotopic data are sparse. We combine new geochronological (LA-ICP-MS zircon U-Pb), geochemical, [...]
Offsetting Carbon Capture and Storage costs with methane and geothermal energy production through reuse of a depleted hydrocarbon field coupled with a saline aquifer
Published: 2019-07-26
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Co-production of methane and geothermal energy from produced subsurface brines with onsite power generation and carbon capture has been proposed as a technically feasible means to reduce the costs of offshore carbon storage sites. In such a facility, methane is degassed from produced brine, this brine is then cooled allowing the extraction of heat and then CO2 is dissolved into it for reinjection [...]
Giant meandering channel systems controlled by sediment supply to the deep-water Campos basin
Published: 2019-07-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Stratigraphy
Large meandering submarine-channel systems are important conduits for mass transfer to continental margins; wider and deeper channels, with larger meanders, reflect larger sediment discharge. Some large meandering channel systems are known to receive voluminous sediment from the largest rivers in the world, such as the Ganges-Brahmaputra, Amazon, Indus, Mississippi, and Zaire (Congo); however, [...]
What is Trishear?
Published: 2019-07-21
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The kinematics of fault-propagation folds, formed above the tips of upward propagating normal faults, is typically inferred from numerical and physical models. Trishear is a forward kinematic model in which deformation occurs in a triangular zone in front of the propagating fault tip, with the geometry of this zone, and the geometry and growth of the resulting fold, related to several parameters [...]
Contrasting TiO2 compositions in Early Cenozoic mafic sills of the Faroe Islands: an example of basalt formation from distinct melting regimes
Published: 2019-07-21
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Abstract: The Paleocene lava succession of the Faroe Islands Basalt Group (FIBG), which is a part of the North Atlantic Igneous Province (NAIP), is intruded by numerous basaltic sills. These can be grouped into three main categories according to their geochemical characteristics: A low-TiO2 sill category (TiO2 = 0.7-0.9), a relatively high-TiO2 sill category (TiO2 = 1.95-2.6) and an [...]
Interaction of Sea-Level Pulses with Periodically Retreating Barrier Islands
Published: 2019-07-19
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics
Barrier deposits preserved on continental shelf seabeds provide a record of the paleocoastal environment from the last glacial maximum through the Holocene. The formation of these offshore deposits is often attributed to intermittent periods of rapidly rising sea levels, especially glacial meltwater pulses, which are expected to lead to partial or complete drowning—overstepping—of migrating [...]
Can barrier islands survive sea-level rise? Quantifying the relative role of tidal deltas and overwash deposition
Published: 2019-07-18
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Environmental Engineering, Geology, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Accepted open-access publication available at: https://doi.org/10.1029/2019GL085524 Barrier island response to sea-level rise depends on their ability to transgress and move sediment onto and behind the barrier, either through flood-tidal delta deposition, or via overwash. Our understanding of these processes over decadal or longer timescales, however, is limited. Here we [...]
Evolution of a shear zone before, during and after melting
Published: 2019-07-18
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Partial melt in the deforming mid/lower continental crust causes a strength decrease and drives formation of lithological heterogeneities. However, mechanisms of formation of syn-melt deformation zones and strain partitioning in partially molten rock remain poorly understood. We use field and microstructural observations to unravel the evolution of a partial melt shear zone, Seiland Igneous [...]
Tectonic stress controls saucer-shaped sill geometry
Published: 2019-07-06
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Saucer-shaped sills are common in sedimentary basins worldwide. The saucer shape relates to asymmetric stress distributions at the sill-tip during intrusion caused by bending of the overburden. Most saucer-shaped sill models are conducted without tectonic stress. Model results are poorly correlated with natural sills in that: (1) modelled saucers are much steeper than natural sills; and (2) [...]