Preprints
Filtering by Subject: Geochemistry
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 [...]
Coupled trace element and Hf-isotope measurements of Hadean through Paleoarchean zircons from the Singhbhum Craton indicate derivation from a long-lived, mantle-derived protocrust
Published: 2025-06-07
Subjects: Earth Sciences, Geochemistry, Geology
Due to the dearth of rock records during the Hadean, little is known about early crustal chemistry and geodynamics. Here, we present zircon trace and rare earth element and Lu-Hf measurements of zircons ~ 3.3 Ga to ~ 4.2 Ga from the Older Metamorphic Tonalitic Gneiss in the Singhbhum Craton to better understand geodynamic changes during the Hadean and Archean. We find decreasing, subchondritic [...]
Improving magmatic CO2 reconstruction using X-ray Computed Tomography to accurately quantify melt inclusion volumes and geometries
Published: 2025-06-04
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology
Melt inclusions provide valuable insights into magmatic systems, allowing the study of otherwise inaccessible melts. Trapped volatile contents, commonly in the form of bubbles within melt inclusions, allow direct sampling and study of magmatic volatiles that are otherwise lost due to saturation and degassing. Quantifying magmatic volatiles such as CO2 is a complex process requiring multiple [...]
The magmatic-hydrothermal transition record in zircon: Implications for zircon texture, composition and rare-metal granite dating (Beauvoir granite, French Massif Central).
Published: 2025-05-30
Subjects: Earth Sciences, Geochemistry
Zircon petrochronology is widely used to quantify the age and duration of magma differentiation and emplacement. However, 20 in highly differentiated magmas, such as those forming rare-metal granites, zircon may form at the magmatic-hydrothermal transition and its primary crystallisation history together with its secondary hydrothermal overprint need to be resolved and clarified. To resolve [...]
Archaean basalts record evidence of lithospheric extension prior to cratonisation
Published: 2025-05-23
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology
The dynamics of Earth’s early mantle remain enigmatic. A wide range of tectonic settings have been proposed for the Archaean eon prior to cratonisation, a time from which few samples are preserved in the geological record. Here, we reexamine this topic by estimating temperatures and depths of melt generation in the late Archaean mantle using a new geochemical data compilation of mafic igneous [...]
Application of mud gas analysis for reservoir evaluation
Published: 2025-05-01
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Mud gas, which is usually used for monitoring the safety of the wells while drilling, can also be used as a formation evaluation tool. This study aims to analyse mud gas ratios and compare them with the traditional formation evaluation tools, such as resistivity. The analysis of four wells, either exploration or development wells, located in differing geological settings, shows that [...]
Calcium isotope constraints on Mesoarchean seawater
Published: 2025-04-24
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Sedimentology
The cause of the Great Oxidation Event ~2.4 billion-years-ago (Ga) is hotly debated. Recent models favor the emergence of continents as driving the event. However, we suggest that extensive shallow-marine carbonate platforms existed in the Mesoarchean. This conclusion is based on Ca isotopes from 2.8 Ga carbonate rocks, that constrains the Ca isotope value of Mesoarchean seawater to -0.5‰ [...]
Deep source regions for Patagonia backarc volcanism imaged by finite frequency body wave tomography
Published: 2025-04-09
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
The subduction of Chile Ridge beneath South America beginning 12-16 Myr ago opened a gap in the subducting slab beneath southern Patagonia, which migrated northward and is located today at 46oS. Geodynamic processes associated with the slab window are poorly understood. Here we apply finite-frequency P and S body wave tomography to seismic data from several temporary arrays as well as regional [...]
A new hypothesis for bimodal volcanism in the Kermadec Arc
Published: 2025-03-29
Subjects: Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology
Bimodal volcanism of basaltic and rhyolitic magmas in the Kermadec Arc has been attributed to the fractional crystallization of basaltic sources. However, new evidence from the Kibblewhite Volcano reveals two distinct differentiation pathways originating from mantle-derived basaltic and andesitic primary magmas. Here we employ geothermobarometric estimations, mass-balance calculations, and [...]
The Petrology, Geochemistry, and Origin of the East Australian Potassic Suite: Bulk Chemistry and Genesis
Published: 2025-03-27
Subjects: Earth Sciences, Geochemistry, Geology, Volcanology
The Eastern Australian Potassic Suite (EAPS) is an alkaline volcanic province made up of over 20 widely dispersed outcrops that extend almost 700 km, forming the southern portion of the world’s longest continental hotspot track, the Cosgrove track. In contrast to the large basaltic volcanic complexes to the east and north, the EAPS occurs exclusively as mafic potassium–rich occurrences with [...]
Weakening of AMOC linked to past Greenland Ice Sheet retreat
Published: 2025-03-21
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Geochemistry, Geology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Paleontology, Physical Sciences and Mathematics
A weakening of the Atlantic Meridional Overturning Circulation (AMOC) is predicted to occur under multiple scenarios of future warming. However, the effect of meltwater from a decaying Greenland Ice Sheet (GrIS) on AMOC is uncertain. Using a basin-wide network of North Atlantic sediment cores, we show that the largescale melting of the GrIS during a previous interglacial (Marine Isotope Stage 11c [...]
Warm deep ocean temperatures from clumped isotopes suggest high climate sensitivity in early Cenozoic hothouse
Published: 2025-03-19
Subjects: Earth Sciences, Geochemistry
The early Cenozoic was characterized by the warmest climates and highest atmospheric CO2 levels of the past 85 Myrs. Reconstructions of deep ocean temperatures based on benthic foraminiferal oxygen isotope records are typically used to infer Earth’s global climate state during this hothouse world. However, this approach requires uncertain assumptions, regarding the seawater isotope composition [...]
Origin of the Harappan Ernestites: Geochemical Insights into Provenance and Fabrication
Published: 2025-03-17
Subjects: Geochemistry, Geology, Other Earth Sciences
Advancements in stone bead technology, particularly in drilling techniques, emerged during the Indus Valley (Harappan) civilization. Long-constricted cylindrical drill bits, made from a unique stone called Ernestite, were a distinctive feature of this culture. The origin of Ernestite is a mystery due to the lack of a natural analogue and an unknown manufacturing process. This study presents a [...]
Modern Cave Monitoring Informs Interpretations of Past Climate Change: Applications to Titan Cave, Wyoming
Published: 2025-03-10
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geochemistry, Geology, Geomorphology, Hydrology, Speleology
Monitoring of cave environments is an essential process for deciphering records of past climate change preserved in the geochemical composition of speleothems, or mineral cave deposits. This study presents data from a multi-year monitoring effort in Titan Cave, Wyoming, a site of interest due to the abundance of speleothems suitable for paleoclimate reconstruction. Titan Cave exhibits annual cave [...]
Orange and Orange-Volcanoes: a New Open and Collaborative Platform to Perform Data-Driven Investigations and Machine Learning Analyses in Petrology and Volcanology
Published: 2025-03-06
Subjects: Earth Sciences, Geochemistry, Multivariate Analysis, Volcanology
Orange-Volcanoes is an extension of the open-source Orange data mining platform specifically tailored for geochemical, petrological, and volcanological investigations. Orange-Volcanoes enhances the original platform by incorporating specialized tools to enable interactive data-driven investigations in geochemistry, such as performing Compositional Data Analysis (CoDA). Applying CoDA [...]