Preprints
Filtering by Subject: Geology
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 [...]
Data-Driven Facies Prediction: A Comparative Study of Random Forest, XGBoost, SVM, CatBoost, and K-Means
Published: 2025-06-11
Subjects: Analysis, Earth Sciences, Geology, Sedimentology
Facies classification plays a critical role in characterizing subsurface heterogeneity and supporting effective reservoir development. Traditional methods, which often rely on core interpretation and manual log analysis, are limited by subjective interpretation and sparse data coverage. This study aims to improve facies prediction by comparing the performance of five machine learning models: [...]
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 [...]
Unprecedented decline in modern coral reef communities could indicate the onset of the Anthropocene
Published: 2025-06-05
Subjects: Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Sciences, Geology, Geomorphology, Stratigraphy
Coral reefs have experienced widespread and accelerated decline, driven by a combination of global and local anthropogenic stressors. To contextualize these changes, we compared the composition of coral reef communities on Curaçao between 1973 and 2023 with that of corals preserved in fossil reefs from the Last Interglacial period (128–116 ka). These fossil reefs, exposed along the island’s [...]
A revised boundary between the Scoor Pelitic Gneiss and the Lagan Mòr Formation in SW Mull?
Published: 2025-05-27
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure
The Moine rocks of SW Mull have played a key role in our understanding of the Moine sequence in the NW Highlands. The Mull sequence was thought uniquely, to contain a continuous sedimentary sequence relating the Morar and Glenfinnan units seen elsewhere in Scotland. However, recent work by Krabbendam et al. (2021) and others, suggests that the Mull sequence does contain a major tectonic break, [...]
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 [...]
Paleo extreme waves in the North Atlantic: geological evidence from Sal Island, Cape Verde Archipelago.
Published: 2025-05-21
Subjects: Earth Sciences, Geology, Geomorphology
The northwestern coast of Sal Island (Cape Verde Archipelago) is characterized by a rocky shoreline that is regularly impacted by Atlantic swells exceeding 4 m in height and 20 s in period. Yet, the only significant geomorphic expression of wave action is an extensive boulder ridge situated atop a rocky cliff, up to 80–100 m inland and between 10 and 15 m above present sea level. The presence of [...]
Decision-making under uncertainty for shallow geothermal systems in complex subsurface settings: application to a low-transmissivity aquifer
Published: 2025-05-08
Subjects: Geology, Hydrology, Natural Resources and Conservation, Sustainability
Excess thermal energy can be stored in the subsurface and recovered when needed to heat and cool buildings sustainably. Aquifer thermal energy storage systems (ATES) are gaining popularity worldwide. Most operational systems are located in thick productive aquifers. Their efficiency and wide applicability have been proven and there is now a tendency to explore more complex settings. Aquifers with [...]
The Apalachicola Barrier Island complex: a benchmark for MIS 5e (125 ka) sea-level oscillations?
Published: 2025-05-06
Subjects: Earth Sciences, Geology, Geomorphology
Coastal sandy barrier systems develop under moderate wave energy, sufficient sediment supply, and adequate accommodation space, and can preserve critical paleoenvironmental records of past sea-level variations, climatic shifts, and storm histories within their geomorphological and stratigraphic frameworks. Beach ridges, identifiable on both horizontal (ridge-swale morphology) and vertical [...]
A SCALABLE MACHINE LEARNING MODELLING TOOL FOR MAPPING LANDSLIDE RUNOUT USING A CASE STUDY IN HAWKES BAY, NEW ZEALAND
Published: 2025-05-02
Subjects: Climate, Earth Sciences, Geology, Geotechnical Engineering, Other Statistics and Probability
Understanding landslide runout is crucial for land use planning, utility networks, and assessing infrastructure resilience on slopes. Recent guidance recommends incorporating landslide runout models along with climate change implications when assessing land for development. The advancement of machine learning (ML) techniques can offer new insights and a tool to be used alongside current methods. [...]
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 [...]
Reliability of Contrast-Based Automated Fracture Detection from Decimeter Resolution Aerial Imagery
Published: 2025-05-01
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geology, Geotechnical Engineering, Other Engineering, Physical Sciences and Mathematics, Tectonics and Structure
Aerial imagery that captures outcrop exposures of rocks enables the characterization of structural discontinuities such as faults and fractures across large and difficult-to-access areas. These datasets provide an opportunity to analyze the characteristics of fault and fracture networks as analogues for the subsurface. The application of automated interpretation methods to imagery has the [...]
Earthquake faults recorded in the near-shore bathymetry of Japan's back-arc
Published: 2025-04-27
Subjects: Geology, Geomorphology, Geophysics and Seismology, Tectonics and Structure
The eastern margin of the Sea of Japan is a zone of great seismic and tsunami hazard due to multiple offshore and nearshore reverse faults as shown by the 2024 Mw 7.5 Noto Peninsula Earthquake. Here we compare coseismic deformation of the 2024 Noto Peninsula Earthquake with 4767 individual marine terraces spanning the last Myr. This reveals that the earthquake faults started slipping between 326 [...]
Calcium isotope constraints on Mesoarchean seawater
Published: 2025-04-25
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 [...]