Preprints
Filtering by Subject: Geology
Volcanic-plutonic parity and the differentiation of the continental crust
Published: 2018-10-04
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology
The continental crust is central to the biological and geological history of Earth. However, crustal heterogeneity has prevented a thorough geochemical comparison of its primary igneous building blocks – volcanic and plutonic rocks – and the processes by which they differentiate to felsic compositions. Our analysis of a comprehensive global dataset of volcanic and plutonic whole-rock geochemistry [...]
Statistical geochemistry reveals disruption in secular lithospheric evolution about 2.5 Gyr ago
Published: 2018-10-03
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Secular cooling of the Earth is required by surface heat loss and declining radiogenic heat production over the last 4.5 billion years. Igneous geochemistry has been used to understand how changing heat flux influenced Archean geodynamics, but records of systematic geochemical evolution are complicated by heterogeneity of the rock record and uncertainties regarding selection and preservation [...]
Plate tectonics and continental basaltic geochemistry throughout Earth history
Published: 2018-10-03
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Basaltic magmas constitute the primary mass flux from Earths mantle to its crust, carrying information about the conditions of mantle melting through which they were generated. As such, changes in the average basaltic geochemistry through time reflect changes in underlying parameters such as mantle potential temperature and the geodynamic setting of mantle melting. However, sampling bias, [...]
Temporal variation in relative zircon abundance throughout Earth history
Published: 2018-10-03
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Zircon is the preeminent chronometer of deep time on Earth, informing models of crustal growth and providing our only direct window into the Hadean Eon. However, the quantity of zircon crystallised per unit mass of magma is highly variable, complicating interpretation of the terrestrial zircon record. Here we combine zircon saturation simulations with a dataset of ∼52,000 igneous whole rock [...]
Vulnerability of Louisiana’s coastal wetlands to present-day rates of relative sea-level rise
Published: 2018-09-30
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Environmental Monitoring, Environmental Sciences, Geology, Geomorphology, Hydrology, Natural Resources Management and Policy, Physical Sciences and Mathematics, Risk Analysis, Sedimentology, Soil Science, Stratigraphy, Sustainability
Coastal Louisiana has lost about 5,000km2 of wetlands over the past century and concern exists whether remaining wetlands will persist while facing some of the world’s highest rates of relative sea-level rise (RSLR). Here we analyse an unprecedented data set derived from 274 rod surface-elevation table-marker horizon stations, to determine present-day surface-elevation change, vertical accretion [...]
Quantifying natural delta variability using a multiple-point geostatistics prior uncertainty model
Published: 2018-09-30
Subjects: Artificial Intelligence and Robotics, Civil and Environmental Engineering, Computer Sciences, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Engineering, Geology, Geomorphology, Other Civil and Environmental Engineering, Other Engineering, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Theory and Algorithms
We address the question of quantifying uncertainty associated with autogenic pattern variability in a channelized transport system by means of a modern geostatistical method. This question has considerable relevance for practical subsurface applications as well, particularly those related to uncertainty quantification relying on Bayesian approaches. Specifically, we show how the autogenic [...]
A revised chronostratigraphic framework for the Aptian of the Essaouira-Agadir Basin, a candidate type section for the NW African Atlantic Margin.
Published: 2018-09-29
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
The Essaouira-Agadir Basin (EAB) of Morocco contains the most extensive exposure of Aptian to Lower Albian strata onshore the NW African Atlantic Margin. This paper documents the first high-resolution, multi-disciplinary stratigraphic approach for the Aptian to Lower Albian on the NW African Atlantic Margin. Previous biostratigraphic work almost exclusively relied on long-distance correlation of [...]
High-temperature shear zone formation in Carrara marble: The effect of loading conditions
Published: 2018-09-26
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Rock deformation at depths in the Earth’s crust is often localized in high temperature shear zones occurring at different scales in a variety of lithologies. The presence of material heterogeneities is known to trigger shear zone development, but the mechanisms controlling initiation and evolution of localization are not fully understood. To investigate the effect of loading conditions on shear [...]
Pleistocene-Holocene tectonic reconstruction of the Ballık travertine (Denizli Graben, SW Turkey): (De)formation of large travertine geobodies at intersecting grabens
Published: 2018-09-25
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Travertine geobodies have been identified as potential reservoir analogues to carbonate build-ups in pre-salt hydrocarbon systems. To investigate travertine geobody deformation, faults were mapped in 35 travertine quarries that excavate the Ballık travertine, i.e. a c. 12.5 km2 large travertine geobody that precipitated at the intersection of the NE margin of the Denizli Basin and neighbouring [...]
Interpretation of low‐temperature thermochronometer ages from tilted normal fault blocks
Published: 2018-09-25
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Low-temperature thermochronometry is a widely-used tool for dating the timing and rate of slip on normal faults. Rates are often derived from suites of footwall thermochronometer samples, but simple 2D regression of age vs. structural depth fails to account for the fact that rocks collected at similar elevations today experienced curved particle trajectories and variable velocities during fault [...]
Statistics and segmentation: Using Big Data to assess Cascades Arc compositional variability
Published: 2018-09-24
Subjects: Applied Mathematics, Applied Statistics, Earth Sciences, Geochemistry, Geology, Multivariate Analysis, Physical Sciences and Mathematics, Statistics and Probability, Volcanology
Primitive lavas erupted in the Cascades arc of western North America demonstrate significant patterns of along-arc heterogeneity. Such compositional diversity may be the result of differences in mantle melting processes, subduction geometry, regional tectonics, or compositions of the slab, mantle or overlying lithosphere. Previous authors have partitioned the arc into four geochemically distinct [...]
Wind tunnel tests inform Ammophila planting spacing for dune management
Published: 2018-09-24
Subjects: Biology, Earth Sciences, Environmental Sciences, Geology, Geomorphology, Life Sciences, Natural Resources Management and Policy, Physical Sciences and Mathematics, Sedimentology
Coastal dunes are invaluable natural resources that bu er upland areas. Vegetation is key in dune development and stabilization. Dunes form with sufficient wind, sand source, and obstruction; plants are the ideal obstruction. Storms o en erode foredunes and coastal managers replant vegetation to re-establish the necessary obstruction for sand accretion and dune growth. We used a wind tunnel to [...]
A New Mechanism for Terrace Formation in Submarine Canyons
Published: 2018-09-24
Subjects: Earth Sciences, Education, Engineering, Geology, Geomorphology, Life Sciences, Physical Sciences and Mathematics, Planetary Geomorphology, Planetary Sciences, Planetary Sedimentology, Sedimentology, Stratigraphy
Deep canyons on Earth occur in both terrestrial and submarine environments, where they are carved by actively incising channels. Apparently similar flights of unpaired terraces, seen at the inside of bends in incised sinuous channels, are also common in both environments. Here we demonstrate a new mechanism for terrace formation that we believe is unique to settings where sediment transporting [...]
Backwater Controls on the Sedimentology, Kinematics and Geometry of Bar Deposits in Coastal Rivers
Published: 2018-09-23
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Geology, Geomorphology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
The backwater reach of coastal rivers is associated with considerable spatial and temporal variability in water and sediment flux. Here we test the hypothesis that the spatial and temporal variability in water flux and particle sizes in transport result in systematic changes in the geometry of bank-attached bars across the backwater transition. Measured transverse slopes of bank-attached bars in [...]
Complex and cascading triggering of submarine landslides and turbidity currents at volcanic islands revealed from integration of high-resolution onshore and offshore surveys
Published: 2018-09-22
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology
Submerged flanks of volcanic islands are prone to hazards including submarine landslides that may trigger damaging tsunamis and fast-moving sediment-laden seafloor flows (turbidity currents) that break critical seafloor infrastructure. Small Island Developing States are particularly vulnerable to these hazards due to their remote and isolated nature, small size, high population densities and weak [...]