Preprints
Filtering by Subject: Geology
Rapid Adjustment of Submarine Channel Architecture to Changes in Sediment Supply
Published: 2018-01-28
Subjects: Earth Sciences, Geology, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Changes in sediment supply and caliber during the last ~130 ka have resulted in a complex architectural evolution of the Y channel system on the western Niger Delta slope. This evolution consists of four phases, each with documented or inferred changes in sediment supply. Phase 1 flows created wide (1,000 m), low-sinuosity (1.1) channel forms with lateral migration and little to no aggradation. [...]
Climbing Ripple Successions in Turbidite Systems: Depositional Environments, Sedimentation Rates, and Accumulation Times
Published: 2018-01-28
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Climbing-ripple cross-lamination (CRCL) is most commonly deposited by turbidity currents when suspended load fallout and bedload transport occur contemporaneously. The angle of ripple climb reflects the ratio of suspended load fallout and bedload sedimentation rates, allowing for the calculation of the flow properties and durations of turbidity currents. Three areas exhibiting thick (> 50 m) [...]
Macrostrat: a platform for geological data integration and deep-time Earth crust research
Published: 2018-01-26
Subjects: Biogeochemistry, Earth Sciences, Geology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Characterizing the lithology, age, and physical-chemical properties of rocks and sediments in the Earths upper crust is necessary to fully assess energy, water, and mineral resources and to address many fundamental questions in the Earth sciences. Although a large number of geological maps, regional geological syntheses, and sample-based measurements have been produced, there is no openly [...]
Detecting orogenic wedge state and the rise of the External Alps by detrital thermochronology
Published: 2018-01-26
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Critical taper theory permits the modelling of an orogenic wedge as a single mechanical entity. However, although shallow-crustal orogens dominated by brittle failure have been successfully modelled using critical taper, this remains controversial for major, ductile-failure-dominated orogens. In critical taper models, the steepness of the basal and upper orogenic surfaces defines the critical [...]
The role of H2O on the extraction of melt from crystallising magmas
Published: 2018-01-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
The segregation and accumulation of felsic melts, from crystallising crustal magma reservoirs, is essential for the chemical evolution of the crust and is a phenomenon preceding some of the largest eruptions on Earth. The physical properties of residual melt and magma and the time over which the conditions remain appropriate for melt extraction are important factors controlling the efficiency of [...]
Two Fundamentally Different Types of Submarine Canyons Along the Continental Margin of Equatorial Guinea
Published: 2018-01-24
Subjects: Earth Sciences, Geology, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Most submarine canyons are erosive conduits cut deeply into the world’s continental shelves through which sediment is transported from areas of high coastal sediment supply onto large submarine fans. However, many submarine canyons in areas of low sediment supply do not have associated submarine fans and show significantly different morphologies and depositional processes from those of ‘classic’ [...]
Facies and Architectural Asymmetry in a Conglomerate-Rich Submarine Channel Fill, Cerro Toro Formation, Sierra Del Toro, Magallanes Basin, Chile
Published: 2018-01-24
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Cross-sectional asymmetry is characteristic of sinuous channels, in both fluvial and submarine settings. Less well documented are the facies distributions of asymmetric channels, particularly in submarine settings. Exposures of the axial channel-belt in the Magallanes retro-arc foreland basin on Sierra del Toro represent the fill of a 3.5 km wide, 300 m thick channel complex, here termed the [...]
Salt thickness and composition influence rift structural style, northern North Sea, offshore Norway
Published: 2018-01-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
‘Salt’ giants are typically halite-dominated, although they invariably contain other evaporite (e.g. anhydrite, bittern salts) and non-evaporite (e.g. carbonate, clastic) rocks. Rheological differences between these rocks mean they impact or respond to rift-related, upper crustal deformation in different ways. Our understanding of basin-scale lithology variations in ancient salt giants, what [...]
Relict topography within the Hangay Mountains in central Mongolia: Quantifying long-term exhumation and relief change in an old landscape
Published: 2018-01-14
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
The Hangay Mountains are a high-elevation, low-relief landscape within the greater Mongolian Plateau of central Asia. New bedrock apatite (U-Th)/He single-grain ages from the Hangay span ~70 to 200 Ma, with a mean of 122.7 ± 24.0 Ma (2σ). Detrital apatite samples from the Selenga and Orkhon Rivers, north of the mountains, yield dominant (U-Th)/He age populations of ~115 to 130 Ma, as well as an [...]
Cenozoic tectonics of the Tuz Gölü Basin (Central Anatolian Plateau, Turkey)
Published: 2018-01-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
We present a new 3D geologic model for the architecture and Cenozoic tectonic evolution of the Tuz Gölü Basin, a major sedimentary basin in the Central Anatolian orogenic plateau. This model is grounded on 7 depth-converted seismic reflection profiles in combination with the analysis of backstripped subsidence curves, isochore maps, and a palinspastically restored cross-section. Two stages of [...]
Climate-driven unsteady denudation and sediment flux in a high-relief unglaciated catchment-fan using 26Al and 10Be: Panamint Valley, California
Published: 2018-01-13
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Environmental changes within erosional catchments of sediment routing systems are predicted to modulate sediment transfer dynamics. However, empirical and numerical models that predict such phenomena are difficult to test in natural systems over multi-millennial timescales. Tectonic boundary conditions and climate history in the Panamint Range, California, are relatively well-constrained by [...]
A consistent global approach for morphometric characterisation of subaqueous landslides
Published: 2018-01-12
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Life Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Landslides are common in aquatic settings worldwide, from lakes and coastal environments to the deep-sea. Fast-moving, large volume landslides can potentially trigger destructive tsunamis. Landslides damage and disrupt global communication links and other critical marine infrastructure. Landslide deposits act as foci for localised, but important deep-seafloor biological communities. Under burial, [...]
Linked Geoscience Data in practice: Where W3C standards meet domain knowledge, data visualization and OGC standards
Published: 2018-01-10
Subjects: Computer Sciences, Earth Sciences, Geology, Physical Sciences and Mathematics
The geoscience community is now facing both the challenge and the opportunity caused by the vast amount of datasets that can be made available on the Web. An efficient “data environment” on the Web has the potential to enable geoscientists to conduct their research in ways that never existed before. Standards developed by the Open Geospatial Consortium have already been used widely to build data [...]
Microstructural controls on the pressure-dependent permeability of Whitby Mudstone
Published: 2018-01-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
A combination of permeability and ultrasonic velocity measurements allied with image analysis is used to distinguish the primary microstructural controls on effective-pressure dependent permeability. Permeabilities of cylindrical samples of Whitby Mudstone were measured using the oscillating pore pressure method at confining pressures ranging between 30-95 MPa and pore pressures ranging between [...]
Estimating regional flood discharge during Palaeocene-Eocene global warming (submitted)
Published: 2018-01-04
Subjects: Climate, Earth Sciences, Environmental Sciences, Geology, Geomorphology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Among the most urgent challenges in future climate change scenarios is accurately predicting the magnitude at which precipitation extremes will intensify. Analogous changes have been reported for an episode of millennial scale 5°C warming termed the Palaeocene-Eocene Thermal Maximum (PETM; 56 Ma), providing independent constraints on hydrological response to global warming. However, quantifying [...]