Preprints
Filtering by Subject: Geology
Middle Jurassic to Early Cretaceous orogenesis in the Klamath Mountains Province (northern California-southern Oregon) occurred by tectonic switching: Insights from Detrital zircon U-Pb geochronology of the Condrey Mountain schist
Published: 2024-01-11
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The Klamath Mountains province (KMP) of northern California and southern Oregon consists of generally east-dipping terranes assembled via Paleozoic to Mesozoic subduction along the western margin of North America. The KMP more than doubled in mass from Middle Jurassic to Early Cretaceous time, due to alternating episodes of extension (e.g, rifting and formation of the Josephine ophiolite) and [...]
Redox Geochemistry of the Late Cambrian SPICE Event in Durness Group, UK
Published: 2024-01-04
Subjects: Earth Sciences, Geochemistry, Geology
The Late Cambrian Steptoean Positive Carbon Isotope Excursion (SPICE) event occurring at approximately 497 Ma and lasting for about 2-4 Myr is emblematic of a global-scale oceanic anoxia, coinciding with the trilobite mass extinction. It is significant in the biotic evolution spanning the Late Cambrian to Ordovician. Nevertheless, the driving mechanism behind the SPICE event is contentious, and [...]
Microbial indicators and detection of Cu-sulfide ore mineralization
Published: 2024-01-02
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Soil Science
Rapid electrification of society is placing unprecedented demand on critical mineral and metal resources. New strategies and technologies are thus needed to promote mineral discovery in regions where deposits are likely buried deep under soil and glacial till. We show that microbial communities from different soil types change in composition in response to amendment with copper. We also show [...]
Will the ‘Anthropocene’ finally be formalized?
Published: 2023-12-08
Subjects: Geology, Stratigraphy
A proposal for the formalization of the ‘Anthropocene’ as a new geological epoch following the Holocene has just been submitted (31 October 2023) to the International Commission on Stratigraphy (ICS). This proposal, prepared by the Anthropocene Working Group (AWG) after 13 years of discussions, places the beginning of the ‘Anthropocene’ in the mid-20th century, and considers that the [...]
A Compilation of Benchmark Pluvial Flood Datasets
Published: 2023-11-29
Subjects: Earth Sciences, Geology
urban pluvial flooding is a dangerous natural hazard that has become more common in recent years, making it a global threat to metropolitan areas. Surface water floods and flash floods are two common types of pluvial flooding that the second one is extremely hazardous and damaging due to both the power of the water and the debris that is frequently swept up in the flow. Buildings and their [...]
Medieval and recent SO2 budgets in the Reykjanes Peninsula: implication for future hazard
Published: 2023-11-23
Subjects: Geochemistry, Geology, Volcanology
Exposure to volcanic SO2 can have adverse effects on human health, with severe respiratory disorders documented on short- and long-term timescales. Here, we use melt inclusion and groundmass glass data to calculate potential syneruptive SO2 emissions during the medieval and the recent, 2021–2024, eruptions across the Reykjanes Peninsula, the most populated area of Iceland, th[AC1] at [...]
Plagioclase-saturated melt hygrothermobarometry and plagioclase-melt equilibria using machine learning
Published: 2023-11-23
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology
Compositions of plagioclase-melt pairs are commonly used to constrain temperatures (T), dissolved water contents (H2O) and pressures (P) of pre-eruptive magma storage and transport. However, previous plagioclase-based thermometers, hygrometers, and barometers can have significant errors, leading to imprecise reconstructions of conditions during plagioclase growth. Here, we explore whether we can [...]
Downsystem Grain-Size Trends and Mass Balance of an Ancient Wave-Influenced Sediment Routing System: Middle Jurassic Brent Delta, Northern North Sea, Offshore UK and Norway
Published: 2023-11-14
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
We reconstruct upsystem-to-downsystem grain-size variations in the sediment routing systems of the data-rich Middle Jurassic Brent Group of the northern North Sea, using published stratigraphic, thickness, palaeogeographic, provenance and age constraints combined with representative core and wireline-log data. Facies associations provide a textural proxy for gravel, sand and mud grain-size [...]
Transgression–regression cycles drive correlations in Ediacaran–Cambrian rock and fossil records
Published: 2023-11-07
Subjects: Earth Sciences, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Statistical Methodology, Statistics and Probability, Stratigraphy
Strata of the Ediacaran Period (635–538.8 Ma) yield the oldest known fossils of complex, macroscopic organisms in the geologic record. These “Ediacaran-type” macrofossils (known as the Ediacaran biota) first appear in mid-Ediacaran strata, experience an apparent decline through the terminal Ediacaran, and directly precede the Cambrian (538.8–485.4 Ma) radiation of animals. Existing hypotheses for [...]
Petrological Evolution and Mass Redistribution in Basaltic Fault Zones: An Example from the Faroe Islands, North Atlantic Igneous Province
Published: 2023-11-06
Subjects: Earth Sciences, Geochemistry, Geology, Tectonics and Structure
Fault rock petrology exerts an important control on the permeability structure and mechanical properties of fault zones. Slip-related deformation on upper-crustal faults in basaltic rocks is closely associated with fluid-rock interaction, altering the distribution of physical properties within the fault. Here we present quantitative descriptions of the geochemical and petrological evolution of [...]
Observations of beach cusp morphodynamics on a composite beach
Published: 2023-11-02
Subjects: Geology, Geomorphology
Substantial volumes of sediment are moved on coarse grained beaches through the formation and destruction of beach cusps, yet the processes governing cusp behaviour remain poorly understood. Here, we combine continuous 2D LiDAR scan data with daily UAV topographic surveys and RGB imagery to provide detailed morphological measurements of beach cusps on a composite beach with the aim to investigate [...]
Quantifying fault interpretation uncertainties and their impact on fault seal and seismic hazard analysis
Published: 2023-10-31
Subjects: Geology, Tectonics and Structure
Fault-horizon cut-off data extracted from seismic reflection datasets are used to study normal fault geometry, displacement distribution, and growth history. We assess the influence of three seismic interpretation factors (repeatability, measurement obliquity, and fault cut-off type) on fault parameter uncertainty. Two repeat interpretations resulted in mean differences of 5-15% for throw, 11-42% [...]
New insights into the Upper Pleistocene directed blast eruption, Popocatépetl volcano, México
Published: 2023-10-30
Subjects: Geology, Stratigraphy, Volcanology
Volcanic eruptions of the directed blast type are characterized by powerful explosions with a significant lateral pyroclastic density current (PDC) component that can travel at speeds above 100 m s–1 and affect hundreds of square kilometers around a volcano. This study presents preliminary results of a detailed fieldwork and stratigraphic study of deposits associated with the Ocoxaltepec Blast [...]
Sediment supply controls on Early Eocene delta sequences (South Pyrenean Foreland Basin; Spain)
Published: 2023-10-13
Subjects: Climate, Geochemistry, Geology, Sedimentology, Stratigraphy
Sediment supply variations are often overlooked when interpreting depositional sequences, which tend to emphasize changes in accommodation. Here, we focus on a temporally well-constrained shallow-marine succession in the South Pyrenean Foreland Basin to test the control of sediment supply on the development of deltaic sequences during the Early Eocene. We analyzed the paleoenvironmental record [...]
The Heavy Mineral Map of Australia Project: A Novel, Rapid, Automated Quantitative Mineralogy Workflow
Published: 2023-10-10
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
The Heavy Mineral Map of Australia (HMMA) is the world’s first project aiming to define a continental heavy mineral baseline. It utilises a novel sample processing workflow and automated mineralogy techniques to rapidly generate and analyse mineralogical data from 1315 archived samples of catchment outlet sediments collected from 1186 catchments across the Australian continent. Heavy [...]