Preprints
Filtering by Subject: Earth Sciences
Evolution of Fluvial Landscapes during the Eocene-Oligocene Transition in Central North America: Reconstructions from Toadstool Geologic Park, Nebraska, U. S. A.
Published: 2024-06-14
Subjects: Earth Sciences, Sedimentology, Stratigraphy
Rivers drive geomorphic change at Earth’s surface by transporting sediment from mountains to sedimentary basins. They are sensitive to changes in water and sediment flux driven by tectonism, climatic perturbation and or volcanism. We characterized changes in fluvial landscapes during a major Cenozoic cooling event, the Eocene-Oligocene Transition (EOT) at 33.9 Ma. The EOT is characterized by a [...]
Paleohydrology of North American Catchments and Rivers at the Onset of the Eocene-Oligocene Climate Transition: Reconstructions from Fluvial Strata of the White River Group, Toadstool Geologic Park, Nebraska
Published: 2024-06-14
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy
Member of the Brule Formation of the White River Group at Toadstool Geologic Park in Nebraska. Our approach combined descriptive and quantitative methods to reconstruct river flow, sediment transport, channel dynamics, floodplain behavior, and catchment-scale moisture variability and ecosystem function. We found that rivers were ephemeral, with peak flow depths and widths of approximately 2.5 m [...]
Repurposing idle wells in the North German Basin as deep borehole heat exchangers
Published: 2024-06-13
Subjects: Earth Sciences
This study investigates the feasibility to repurpose wells from gas produc-tion for geothermal closed loop application in the North German Basin (NGB). The objective is to extend the value-added chain of idle wells by re-completion as coaxial deep borehole heat exchangers as an efficient way to produce green energy without drilling new wells by saving the carbon emis-sion and costs of building a [...]
Exploring coastal climate adaptation through storylines: Insights from Cyclone Idai in Beira, Mozambique
Published: 2024-06-11
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Environmental Engineering, Environmental Sciences, Hydraulic Engineering, Hydrology, Meteorology, Natural Resources Management and Policy, Water Resource Management
Coastal settlements, facing increasing flood risk from Tropical Cyclones (TCs) under climate change, need local and detailed climate information for effective adaptation. Analysis of historical events and their impacts provides such information. This study uses storylines to evaluate adaptation strategies, focusing on Cyclone Idai’s impact on Beira, Mozambique, under different climate [...]
Linking petrographic and geochemical indicators of melt reactions in pelitic migmatites and leucogranites
Published: 2024-05-31
Subjects: Earth Sciences
Anatexis in orogenic systems has wide-reaching implications for the structure, mechanical strength, and later exhumation of the middle crust during orogeny. Previous studies of melt reactions in metapelitic rocks have identified three major melt-producing reactions: fluid-present incongruent melting, fluid-absent muscovite dehydration melting, and fluid-absent biotite dehydration melting. Due to [...]
Opening doors to physical sample tracking and attribution in Earth and environmental sciences
Published: 2024-05-31
Subjects: Biochemistry, Biophysics, and Structural Biology, Earth Sciences, Ecology and Evolutionary Biology, Environmental Sciences, Life Sciences, Microbiology, Physical Sciences and Mathematics, Systems Biology
Physical samples and their associated (meta)data underpin scientific discoveries across disciplines and can enable new science when appropriately archived. However, there are significant gaps in current practices and infrastructure that prevent accurate provenance tracking, reproducibility, and attribution. For most samples, descriptive metadata are often sparse, inaccessible, or absent. Samples [...]
Unique composition and evolutionary histories of large low velocity provinces
Published: 2024-05-31
Subjects: Earth Sciences, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics
The two ``large low velocity provinces'' (LLVPs) are broad, low seismic wave speed anomalies in Earth's lower mantle beneath Africa and the Pacific Ocean. Recent research suggests they contain relatively dense subducted oceanic crust (SOC), but the relative concentration of this recycled material within them is an open question. Using simulations of 3-D global mantle circulation over the past 1 [...]
Predictable recovery rates in near-surface materials after earthquake damage
Published: 2024-05-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquakes introduce transient mechanical damage in the subsurface, which causes postseismic hazards and can take years to recover. This observation has been linked to relaxation, a phenomenon observed in a wide class of materials after straining perturbations, but its duration after earthquake ground shaking has not been constrained. Here, we analyse the effects of two successive large [...]
Evolution and architecture of an overbank in an ocean-facing canyon-fill.
Published: 2024-05-21
Subjects: Earth Sciences, Geology, Sedimentology
Submarine canyon-fills comprise substantial volumes of thin-bedded successions deposited by sediment gravity flows that are either stripped or overspill from adjacent channels into highly confined, topographically complex overbank settings. Here, we document the Punta Baja Formation, a rare example of an exhumed canyon-confined overbank succession with good 3D constraints from the Mesozoic [...]
At the Sharp End of Fractured Granites: A Critical Geology for Critical Times
Published: 2024-05-20
Subjects: Earth Sciences, Human Geography, Physical Sciences and Mathematics, Social and Behavioral Sciences
The geosciences have been positioned as integral to a ‘whole society’ transition that includes the decarbonisation of energy systems. Geothermal energy - which relies on a knowledge of the dynamism of rocks in the subsurface including the movement of fluids through fractures, physio-chemical interactions, and thermal gradients – has been offered as a potential route forward. Its realisation [...]
A model of near-sea ice phytoplankton blooms
Published: 2024-05-20
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Arctic phytoplankton spring blooms have increased in magnitude and extent over the past two decades, particularly in waters near the sea ice edge. We develop an idealized model of phytoplankton dynamics that takes into account the role of sea ice meltwater flux and its impact on surface mixed layer depth. Satellite observations feature a characteristic peak in phytoplankton concentration at [...]
Bayesian Inversion with TimeOptMCMC
Published: 2024-05-16
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Statistical Methodology, Stratigraphy
TimeOptMCMC (Meyers and Malinverno, 2018) is a Bayesian approach for evaluating cyclostratigraphic records that quantitatively links geologic data with astronomical theory. This manuscript provides an introductory guide for conducting a TimeOptMCMC Bayesian inversion, following the approach of Meyers and Malinverno (2018). The purpose of this guide is to help users identify an appropriate data [...]
Direct observations of transient weakening during phase transformations in quartz and olivine
Published: 2024-05-13
Subjects: Earth Sciences, Geology, Mineral Physics, Tectonics and Structure
Phase transformations are widely invoked as a source of rheological weakening during subduction, continental collision, mantle convection, and various other geodynamic phenomena. However, despite more than half a century of research, the likelihood and magnitude of such weakening in nature remain poorly constrained. Here, we use experiments performed on a synchrotron beamline to reveal transient [...]
Ultramafic Melt Viscosity: A Model
Published: 2024-05-13
Subjects: Earth Sciences, Physical Sciences and Mathematics, Planetary Sciences
A non-Arrhenian model for the Newtonian viscosity (η) of ultramafic melts is presented. The model predicts the viscosity of ultramafic melts as a function of temperature (T), pressure (P), H2O content and for a range of melt compositions (70 < Mg# < 100). The calibration consists of 63 viscosity measurements at ambient pressure for 20 individual melt compositions and 5 high-P measurements [...]
Permafrost thaw subsidence, sea-level rise, and erosion are transforming Alaska’s Arctic coastal zone
Published: 2024-05-10
Subjects: Earth Sciences, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics
Climate warming is causing rapid coastal change in the Arctic. Permafrost thaw subsidence, sea-level rise, and erosion each threaten the Arctic nearshore. These agents of change have received unequal attention and their compound impact remains poorly understood. Alaska's Arctic Coastal Plain (ACP) is ideal for addressing this knowledge gap due to the region’s relatively abundant observational [...]