Preprints
Filtering by Subject: Geochemistry
Impact of sources and form of Mg on oyster shell Mg/Ca
Published: 2025-09-17
Subjects: Geochemistry
Mg/Ca in bivalve shells has been investigated as a promising temperature proxy, but several studies reported compositional shifts that hamper its accuracy. In particular, several models linking shell Mg/Ca and temperature have been published and an empirical difference in the seasonal amplitudes of shell Mg/Ca has been observed between two types of environmental settings: river output, open [...]
A Hybrid Iron/Green-Rust-Urea Model for Prebiotic Chemistry: A Synthesis of Testable Pathways for Planetary Astrobiology
Published: 2025-09-17
Subjects: Earth Sciences, Geochemistry, Planetary Geochemistry, Planetary Geology, Planetary Hydrology, Planetary Sciences
We propose a quantitative, testable framework for abiogenesis that links submarine alkaline vents, which supply H₂, ΔpH, and Fe/Fe–S catalysis, to subaerial hot-spring fields that provide wet–dry concentration and UV-driven photoredox chemistry. To bridge dilution between environments, we specify mobile “holding pens” (green-rust/iron flocs, silica mats, pumice rafts, and sea-surface [...]
Using X-ray Fluorescence to Detect Automobile Heavy Metal Pollution in Los Angeles Soils with Copper and Palladium as Indicators
Published: 2025-08-29
Subjects: Earth Sciences, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Geochemistry, Physical Sciences and Mathematics
This project evaluates the effectiveness of using portable X-ray Fluorescence (XRF) to detect soil composition matrices that show patterns of anthropogenic influence. We explore 26 areas within Los Angeles County, California, that have various amounts of traffic; classifying each locale as Urban or Recreational. The main elements of interest are copper and palladium. These indicators are largely [...]
An Ice Core Snapshot of Past Atmospheric Chemistry in Mt. Everest’s 'Death Zone'
Published: 2025-08-21
Subjects: Earth Sciences, Environmental Sciences, Geochemistry, Glaciology, Other Environmental Sciences, Physical Sciences and Mathematics
We present a unique atmospheric chemistry record from the highest ice core ever recovered (8020 m, South Col Glacier (SCG), Mt. Everest), that captures ~400 years of deposition during the latter half of the first millennium BCE. Due to recent glacier thinning, the upper ~2000 years of accumulation have been lost, however, this is the only ice core record ever recovered from the “Death Zone [...]
Controls on Mg isotopic fractionation between deep mantle phases and relict signatures of a terrestrial magma ocean
Published: 2025-08-07
Subjects: Geochemistry, Mineral Physics
We use density functional theory to investigate the fractionation of Mg isotopes between phases in the lower mantle. Our results support previous work and show that coordination number plays an important role in controlling isotopic fractionation, with bridgmanite (perovskite-structured MgSiO3) preferentially incorporating lighter Mg isotopes into its highly coordinated site compared to periclase [...]
A novel experimental V-Sc olivine-melt oxybarometer for arc magmas
Published: 2025-07-30
Subjects: Earth Sciences, Geochemistry
Redox conditions significantly affect phase equilibria, the availability and mobility of heterovalent elements, including volatiles (i.e., S) and metals (e.g., Fe, Cu) in silicate melts. Gaining a deeper understanding of the initial redox state of magmas may help better understand magmatic ore fertility, volcanic degassing, and the redox evolution of Earth's crust and atmosphere. This study [...]
Geochemical characteristics of orthopyroxene-bearing metamorphosed lithologies in the northern Chilka lake area, Eastern Ghats belt, India: Insights into the original nature and petrogenesis of precursors
Published: 2025-07-25
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
The northern Chilka Lake area stone quarries expose a high-grade terrane comprising a metapelitic suite interbanded with orthopyroxene-bearing gneisses and garnet-biotite leucogneisses (leptynites). This study presents bulk-rock and mineral chemistry data of the orthopyroxene-bearing units to evaluate the true nature of their protoliths and to comment on their petrogenesis. Field, petrographic, [...]
Assessing uncertainty of source rock properties using Monte Carlo basin modeling – Application to Canning Basin, Australia
Published: 2025-07-23
Subjects: Applied Statistics, Earth Sciences, Engineering, Environmental Sciences, Geochemistry, Geology, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Risk Analysis, Statistics and Probability, Stratigraphy
This study presents a Monte Carlo basin modeling framework for quantifying uncertainty in source rock property predictions by integrating geological, geophysical, and geochemical inputs. The approach accounts for variability in petrological parameters from rock physics inversion, paleo-erosion magnitudes, organic facies properties, and boundary conditions to simulate source rock properties such [...]
Impact of oxygen release from bentonite on microbial activity, mineralogy, and steel corrosion
Published: 2025-07-19
Subjects: Civil Engineering, Environmental Engineering, Environmental Microbiology and Microbial Ecology Life Sciences, Geochemistry
Deep geological repositories for the disposal of radioactive waste rely partly on the integrity of canisters and on the inhibition of microbial growth by the bentonite barrier for the effective isolation of the waste from the environment. Canister integrity can be compromised by the activity of sulfate-reducing bacteria (SRB) and by abiotic corrosion. Unexpected aerobic microbial growth and SRB [...]
Volcano-tectonic controls on magmatic evolution at Campi Flegrei, Italy: insights from thermodynamic modelling
Published: 2025-07-14
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology
Campi Flegrei caldera (Naples, southern Italy) is one of the most hazardous volcanoes on Earth, having produced more than 70 eruptions in the past 15 kyr, and currently showing significant signs of unrest within a densely populated part of Europe. Post-15 ka eruptions span a range of eruptive styles and compositions, which broadly correlate with the spatial and structural location of vents within [...]
Constraining the paleoclimate and paleoecology of the Selandian – Thanetian transition in the Lower Wilcox, Texas Gulf Coast
Published: 2025-07-08
Subjects: Earth Sciences, Geochemistry, Sedimentology, Stratigraphy
The Selandian–Thanetian Transition Event (STTE) represents a relatively understudied interval of carbon cycle instability and environmental disruption during the Paleocene. This study presents a comprehensive sedimentological, palynological, and geochemical record of the STTE based on two shallow marine wells (Moczygemba VT #11 and Vogelsang Frieda #1) from the Texas Gulf Coast. Our multi-proxy [...]
Machine Learning Insights into the Geochemical Life Cycle of the Columbia River Flood Basalts
Published: 2025-07-02
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Stratigraphy, Volcanology
Flood basalts are challenging to characterize in detail, despite enormous their erupted volumes, due to their age and chemical homogeneity. Here we explore machine learning (ML) approaches for classification and pattern identification in whole rock geochemical data of the Columbia River Flood Basalts (CRFB), which provide key constraints on magma generation, transport, and emplacement. We utilize [...]
Continental-Scale Carbonate Sedimentation and Environmental Correlates of the Shuram-Wonoka Excursion
Published: 2025-07-01
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Strata of the Ediacaran Period record many Earth-Life features that distinguish the Neoproterozoic-Phanerozoic transition. However, it is difficult to determine cause and effect relationships between Ediacaran events. Continental-scale patterns of sedimentation have been used as proxies to investigate controls on Phanerozoic macroevolution, including sea level drivers and potential carbon cycling [...]
CO2-Based Leaching of Sulfidic Peridotite Drives Critical Mineral Mobilization and Carbonate Precipitation
Published: 2025-06-20
Subjects: Earth Sciences, Geochemistry, Geology
The transition towards green energy requires both carbon dioxide removal and consistent supplies of energy-critical minerals. Injection and mineralization of supercritical CO2 at active mafic and ultramafic-hosted mines provides a potential avenue to achieve both, through the stable geologic storage of carbon and subsequent mobilization of critical metals. A sample from the Eagle occurrence, an [...]
Quantifying sulfur speciation in magmatic-hydrothermal fluids
Published: 2025-06-11
Subjects: Chemistry, Earth Sciences, Geochemistry, Geology, Inorganic Chemistry, Natural Resource Economics, Physical Chemistry, Physical Sciences and Mathematics
Quantitative knowledge of sulfur speciation in the fluid phase is key to understanding sulfur degassing from magmas and its transfer along with metals by fluids across the lithosphere. Farsang and Zajacz(1) recently reported new sulfur speciation data using Raman spectroscopy measurements on aqueous H2SO4-NaCl(-KCl) solutions trapped as synthetic fluid inclusions in quartz at 875 °C and 2 kbar [...]