Preprints
Filtering by Subject: Geochemistry
From "Ion-Adsorption" to "Ion-Adsorbed" Rare Earths: Terminological Drift, AI Paraphrasing, and the Erosion of Geochemical Precision
Published: 2026-03-17
Subjects: Earth Sciences, Geochemistry
The rapid adoption of artificial intelligence (AI) tools for writing and paraphrasing is transforming scientific communication. While such tools can improve linguistic fluency, their misuse, particularly when employed to mechanically rephrase text, may introduce subtle but consequential distortions in scientific terminology. In disciplines such as geochemistry, where terminology is closely tied [...]
Trace element contamination of sand samples by grinding
Published: 2026-03-11
Subjects: Earth Sciences, Environmental Sciences, Geochemistry
Blanks during powdering processes were examined for major and trace elements using inductively coupled plasma mass spectrometry (ICP-MS). Quartz sand (reference CV32.2) was used as a test substrate for powdering with grinding mills of several kinds: an agate mortar grinder, a stainless steel mortar grinder, a hard porcelain mortar grinder, an agate hand mill, and a hard porcelain hand mill. The [...]
Stable isotopic composition, paleoecology, and habitat of the ammonite Sphenodiscus lobatus in the Late Cretaceous (Maastrichtian) Western Interior Seaway
Published: 2026-03-04
Subjects: Earth Sciences, Geochemistry, Paleobiology, Paleontology, Sedimentology
Despite their abundance as fossils, the life histories of ammonites are still poorly understood. We analyzed the oxygen (δ18O) and carbon (δ13C) isotopic composition of well-preserved shell material taken from different growth stages of the streamlined oxyconic ammonite species Sphenodiscus lobatus from the Upper Cretaceous (Maastrichtian) Pierre Shale and Fox Hills Formation of South Dakota. [...]
Biotite/melt trace-element, lithium, and F-OH partitioning in silicate magmas
Published: 2026-02-18
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: 2026-02-14
Subjects: Geochemistry, Geology, Mineral Physics, Physical Sciences and Mathematics, Volcanology
The Rothplattenbach Complex (Arosa Zone, Germany) hosts alkaline magmatic rocks that provide unique insights into the mid-crustal evolution of water-saturated melts. This study presents a detailed phase-analytical investigation using XRD and SEM/EDX to characterize the primary magmatic mineralogy and its subsequent autometasomatic alteration. A key discovery is the occurrence of primary magmatic [...]
Multiple-Well Monitoring Site Adjacent to the Midway- Sunset and Buena Vista Oil Fields, Kern County, California
Published: 2026-02-13
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: 2026-01-31
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 mean 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, [...]
A New Paradigm for High-Level Radioactive Waste Disposal: Intrinsic Radionuclide Properties and Comparative Hazard
Published: 2026-01-22
Subjects: Environmental Engineering, Environmental Sciences, Geochemistry, Geology
Disposal regulations and technologies for high-level radioactive waste have evolved separately from other hazardous wastes, despite shared concerns about long-term risks. This study compares these historical trajectories and reassesses the hazard profile and physical/geochemical properties of key radionuclides. Long-lived radionuclides have low specific activity and emit little or no penetrating [...]
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 Archaean 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 Archaean oceans became salty. Here, we present new triple halogen (Cl-Br-I) data from high [...]
A crystal-scale record of recharge and mixing at Rabaul Volcano (Papua New Guinea)
Published: 2026-01-21
Subjects: Earth Sciences, Geochemistry, Volcanology
Rabaul is a densely populated caldera volcano in Papua New Guinea that last erupted a caldera-forming volume ~1,400 years ago and has produced numerous intra-caldera eruptions since. Its erupted compositions have commonly been attributed to fractional crystallisation, and although mafic enclaves point to a role for mafic recharge and magma mixing, no study has yet used the crystal cargo itself to [...]
The magnitude of equilibrium isotope fractionation of Mg between forsterite, diopside and melt at liquidus temperatures
Published: 2026-01-12
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: 2026-01-02
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: 2025-12-13
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 islands revealed by clinopyroxene from La Palma
Published: 2025-12-04
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 variations operate in low-flux ocean island volcanoes remains poorly constrained, leaving a key gap in understanding eruption precursors. Here we examine the temporal evolution of magmatic processes recorded in clinopyroxene [...]
Oxidation state of Mayotte magmatic series: insights from Fe and S K-edge XANES spectroscopy
Published: 2025-11-28
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 [...]