Preprints
Filtering by Subject: Geochemistry
Biotite/melt trace-element, lithium, and F-OH partitioning in silicate magmas
Published: 2026-02-17
Subjects: Earth Sciences, Geochemistry, Inorganic Chemistry, Materials Chemistry, Other Earth Sciences
Biotite is a key hydrous silicate mineral in evolved magmatic systems, but its control on the behaviour of minor- and trace-elements, in particular Li, Nb, F and the REE is not well understood. Here, we quantify that control in sodic (per)alkaline H2O-saturated magmas with variable F-content through crystallisation experiments at 650–800◦C and 200 MPa total pressure, at log f O2 ≈ FMQ +1. [...]
Mid-crustal Origin of Alkaline Magmas in the Arosa Zone: Evidence from Primary Analcime and Xenolith Interaction at the Rothplattenbach Complex (Germany)
Published: 2026-02-13
Subjects: Geochemistry, Geology, Mineral Physics, Physical Sciences and Mathematics, Volcanology
The petrogenetic evolution of the alkaline magmatic rocks of the Rothplattenbach Complex was investigated by X-ray diffraction phase analysis and crystallographic lattice-parameter determination. The study focuses on the identification of primary analcime occurring in paragenesis with Ca-rich plagioclase (An₇₇) and diopsidic clinopyroxene. Phase-equilibrium modelling indicates that magma [...]
Multiple-Well Monitoring Site Adjacent to the Midway- Sunset and Buena Vista Oil Fields, Kern County, California
Published: 2026-02-12
Subjects: Earth Sciences, Geochemistry, Geology, Hydrology, Physical Sciences and Mathematics
Groundwater quality in and around oil fields in the Southern San Joaquin Valley is of interest to many California residents that rely heavily on groundwater for domestic, commercial, and agricultural use. To help assess the effects of historical oil-field activities and natural geologic sources on groundwater near the southwest margins of the Kern County Groundwater Subbasin, a multiple-well [...]
Magmatic volatile budgets of the 2014 Tavurvur eruption at Rabaul Caldera, Papua New Guinea
Published: 2026-01-30
Subjects: Earth Sciences, Geochemistry, Volcanology
Rabaul is a caldera volcano on New Britain Island, Papua New Guinea, whose active cone Tavurvur ranks seventh globally for long-term SO2 and CO2 emissions. It is unknown why Rabaul is such a strong emitter of volcanic gases. Magma mixing between basaltic and dacitic magmas is envisioned to play a fundamental role in driving eruptions at Rabaul, but the compositions of mafic recharge magmas and [...]
A New Paradigm for High-Level Radioactive Waste Disposal: Intrinsic Radionuclide Properties and Comparative Hazard
Published: 2026-01-21
Subjects: Environmental Engineering, Environmental Sciences, Geochemistry, Geology
This paper develops a hazard- and pathway-based framework for high-level radioactive waste (HLW) disposal grounded in intrinsic radionuclide decay characteristics, geochemical behavior, and comparative hazard. We examine the physical and geochemical properties of key radionuclides and quantify lifetime cancer risk from chronic ingestion on a per-unit-mass basis using established regulatory [...]
Magmatic degassing as the primary source of salt in Archean oceans
Published: 2026-01-21
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
The salinification of Earth’s early oceans impacted both the climate and the evolution of life. However, available halogen data of Archean seawater samples are at apparent odds with a conventionally assumed mantle origin of sea salt, highlighting a critical lack of mechanistic understanding of how the Archean oceans became salty. Here, we present new triple halogen (Cl-Br-I) data from high [...]
Petrological insights into magma storage and evolution at Rabaul Caldera, Papua New Guinea
Published: 2026-01-21
Subjects: Earth Sciences, Geochemistry, Volcanology
Rabaul is a caldera volcano in Papua New Guinea. Its most recent caldera-forming eruption occurred ~1400 years ago, with numerous intra-caldera eruptions since. Erupted whole rock compositions are commonly attributed to fractional crystallisation along a single liquid line of descent, but mafic mineral clots indicate mafic recharge and magma mixing also influence whole rock compositions. [...]
The magnitude of equilibrium isotope fractionation of Mg between forsterite, diopside and melt at liquidus temperatures
Published: 2026-01-11
Subjects: Earth Sciences, Geochemistry, Mineral Physics
We examine the equilibrium fractionation of Mg isotopes between forsterite, diopside, and a coexisting melt at liquidus temperatures using a combination of analyses of petrological-experiment products and atomic-scale simulations. Our experiment yields ∆²⁶Mgol/melt = -0.058 ± 0.032 ‰ (2s.e.) and ∆²⁶Mgcpx/melt = 0.060 ± 0.034 ‰ (2s.e.) for crystals grown from a near-cotectic basaltic melt in the [...]
Reviewing chronostratigraphic uncertainty of the Ediacaran-Cambrian transition
Published: 2026-01-01
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Stratigraphy
The Ediacaran-Cambrian transition archives the widespread disappearance of ‘Ediacaran-type’ soft-bodied biota and the appearance of most modern animal body plans, including a major diversification of skeletal animals and styles of animal-substrate interaction. Despite over a century of study, our ability to confidently reconstruct the series of macroevolutionary events that inform origination and [...]
Solubility and speciation of sulfur in silicate melts under crustal conditions
Published: 2025-12-12
Subjects: Earth Sciences, Geochemistry, Geology, Volcanology
We have determined the solubility of sulfur as either sulfide (S2-) or sulfate (S6+) in a wide range of silicate melts at 1 atm pressure and temperatures of 1050° to 1250°C. The method involved suspension of the melt in either a mixture of CO2-CO-SO2 (sulfide solubility) or SO2 and air (sulfate solubility) for periods of up to 120 hours. Sulfur concentrations, measured by electron microprobe were [...]
Recurrent evacuation of mantle mush by mafic recharge in ocean island basalts, recorded by La Palma clinopyroxene
Published: 2025-12-03
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology
Temporal variations in magma plumbing architecture and magmatic processes influence eruption priming and the interpretation of pre- and syn-eruptive signals. Yet, how these processes operate in low-flux volcanoes remains poorly constrained, leaving a key gap in understanding eruption precursors. Here we examine the temporal evolution of magmatic processes at La Palma, Canary Islands, a low-flux [...]
Oxidation state of Mayotte magmatic series: insights from Fe and S K-edge XANES spectroscopy
Published: 2025-11-27
Subjects: Earth Sciences, Geochemistry, Volcanology
Following the 2018-2020 Fani Maoré submarine eruption near Mayotte Island, Indian Ocean, multiple oceanographic expeditions provide unprecedented access to fresh alkaline volcanic glasses spanning basanite to phonolite compositions from the East-Mayotte Volcanic Chain (EMVC). We applied Fe and S K-edge X-ray Absorption Near-Edge Spectroscopy (XANES) to determine iron and sulfur oxidation states [...]
Crystalline silica content of natural, engineered, and synthetic stone products and their relation to silicosis policy development
Published: 2025-11-12
Subjects: Earth Sciences, Geochemistry, Geology, Materials Science and Engineering, Public Health
Crystalline silica minerals – quartz, cristobalite, and tridymite – are hazardous when inhaled. They are at least an order of magnitude more toxic than crystalline silica-free inert mineral dusts. Workplace exposure to hazardous levels of crystalline silica is entirely preventable, yet accelerated silicosis is emerging in developed countries, from the fabrication of crystalline silica-rich [...]
Effect of chemical disequilibrium during metal-silicate partitioning on the thermal state of the early core and implications on the dynamics of metal/silicate segregation
Published: 2025-11-05
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Planetary Geology, Planetary Geophysics and Seismology
In this study, we improved a previously published numerical model linking the core composition to the core temperature during accretion by introducing some amount of chemical disequilibrium during the segregation of the core in the magma ocean phase. At the minimum equilibrium rate in metal and silicate phases, the final temperature of the core by $\sim$ 250 K compared to the fully equilibrated [...]
Radiogenic Sr-Nd-Pb isotope behavior in different grain-sized fine lithic materials during basalt weathering
Published: 2025-10-15
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Geochemistry, Geology, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Sedimentology, Stratigraphy
Radiogenic isotopes are widely used as sediment provenance tracers; however, their weathering response has not been fully established. This study investigates the weathering sensitivity of Sr-Nd-Pb isotopes in fine lithic fractions (FLF; grain size <2 μm, <5 μm, and <20 μm) capable of long-range transport. Geochemical and isotope compositions have been measured in the physicochemically [...]