Preprints
Filtering by Subject: Geochemistry
Freshwater plume-like condition near the north-eastern coastal Arabian Sea during early Miocene: Evidence from the stable isotope record in the growth bands of gastropods (Turritella sp.)
Published: 2024-01-30
Subjects: Climate, Earth Sciences, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology
The Early Miocene witnessed major tectonic, palaeoceanographic and climatological reorganizations over the Asian realm. The Himalayan and Tibetan plateau upliftment influenced monsoon intensity during this age. Contemporary high-resolution tropical hydroclimate records are limited. Here, we present an early Miocene sub-annual stable isotope record from the growth bands of well-preserved [...]
River Floodplains, Organic Carbon, and Paleoclimate: How River Dynamics Impart Biases in the Biogeochemical Climate Record of Terrestrial Landscapes
Published: 2024-01-28
Subjects: Earth Sciences, Geochemistry, Geomorphology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
River floodplains can be both sources and sinks for organic carbon. In the sedimentary record, geochemical signatures of terrestrial water availability record climate and ecology along river corridors in deep time. However, paleoenvironmental reconstructions are often confounded by the complex dynamics of organic carbon residence, entrainment, and deposition in a fluvial system. As alluvial [...]
Magmatic Controls on Volcanic Sulfur Emissions at the Iceland Hotspot
Published: 2024-01-14
Subjects: Geochemistry, Geology, Volcanology
Outgassing of S (as SO2) is one of the principal hazards posed by volcanic eruptions. However, S emission potentials of most volcanoes globally are poorly constrained due to a short observational record and an incomplete understanding of the magmatic processes that influence pre-eruptive S concentrations. Here, we use a compilation of published and new data from melt inclusions—which [...]
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 [...]
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 [...]
Changes in mesophotic carbonate-platform export across the end of the last glacial cycle (Saya de Malha Bank, western Indian Ocean)
Published: 2023-11-07
Subjects: Biogeochemistry, Geochemistry, Natural Resources and Conservation, Other Earth Sciences, Other Environmental Sciences, Paleobiology, Sedimentology, Stratigraphy
The export of neritic material from the top of carbonate platforms is a key process in the construction of their slopes. However, our knowledge of the supply pattern of materials from platforms is dominantly based on platforms lying in the euphotic zone during the present sea-level highstand. This is a somewhat biased perspective as through geological time not all platforms were euphotic. The [...]
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 [...]
PyIRoGlass: An Open-Source, Bayesian MCMC Algorithm for Fitting Baselines to FTIR Spectra of Basaltic-Andesitic Glasses
Published: 2023-11-02
Subjects: Earth Sciences, Geochemistry, Other Earth Sciences, Physical Sciences and Mathematics, Volcanology
Quantifying volatile concentrations in magmas is critical for understanding magma storage, phase equilibria, and eruption processes. We present PyIRoGlass, an open-source Python package for quantifying H2O and CO2 species concentrations in the transmission FTIR spectra of basaltic to andesitic glasses. We leverage a database of naturally degassed melt inclusions and back-arc basin basalts to [...]
Petrographic and geochemical evidence for a complex magmatic plumbing system beneath Bagana volcano, Papua New Guinea
Published: 2023-10-31
Subjects: Earth Sciences, Geochemistry, Volcanology
Bagana is a persistently active stratovolcano located on Bougainville Island, Papua New Guinea. Characteristic activity consists of prolonged lava effusion over months to years, with occasional shifts to explosive vulcanian or subplinian eruptions which threaten surrounding communities. Satellite observations have shown that Bagana is a major SO2 emitter, particularly during eruptive intervals. [...]
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 [...]
Coral geochemical response to uplift in the aftermath of the 2005 Nias-Simeulue earthquake
Published: 2023-10-07
Subjects: Environmental Indicators and Impact Assessment, Geochemistry, Geomorphology, Natural Resources and Conservation, Tectonics and Structure
On 28 March 2005, the Indonesian islands of Nias and Simeulue experienced a powerful Mw 8.6 earthquake and widespread co-seismic uplift and subsidence. In areas of coastal uplift (up to ~2.8 m), fringing reef coral communities were killed by exposure, while deeper corals that survived were subjected to habitats with altered runoff, sediment and nutrient regimes. Here we present time-series [...]
A shift in the Sr isotopic composition of the magmatic source triggering 2019 paroxysmal eruptions at Stromboli Volcano
Published: 2023-10-05
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology
The persistent volcanic activity of Stromboli Volcano, Aeolian Islands, Italy, is interrupted by paroxysmal eruptions on a decadal interval. In 2019, two strong paroxysms on July 3rd and August 28th, ended a more than a decade long period of regular strombolian activity. During normal strombolian activity the volcano erupts highly porphyritic scoria and lava (HP)20 with a shoshonitic basalt [...]