Preprints
Filtering by Subject: Geochemistry
Created by the Monte Peron rock avalanche: Lago di Vedana (Dolomites, Italy) and its sediment record of landscape evolution after a mass wasting event
Published: 2021-07-09
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology
The timing of the Monte Peron Landslide is revised to 2890 cal. BP based on a radiocarbon-dated sediment stratigraphy of Lago di Vedana. This age fosters the importance of hydroclimatic triggers in the light of accelerating global warming with a predicted increase of precipitation enhancing the regional predisposition to large landslides. Moreover, a layer enriched in allochthonous organic and [...]
Carbonate polymorphism controlled by microbial iron redox dynamics at a natural CO2 leakage site (Crystal Geyser, Utah)
Published: 2021-07-07
Subjects: Geochemistry, Geology, Sedimentology
Crystal Geyser (Utah, USA) is a CO2-rich low-temperature geyser that is studied as a natural analog for CO2 leakage from carbon capture and storage (CCS) sites. In order to better constrain the biogeochemical processes influencing CaCO3 precipitation at geological CO2 escape sites, we characterized fast-forming iron-rich calcium carbonate pisoids and travertines precipitating from the fluids [...]
Cosmogenic 3He in terrestrial rocks: a review
Published: 2021-07-05
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Glaciology, Other Earth Sciences
This review article summarizes the state of the art of cosmogenic 3He (3Hec), with a focus on the most efficient methods and strategies for measuring this cosmogenic noble gas in the terrestrial minerals. Our ability to accurately and precisely measure cosmogenic 3He in minerals is mainly constrained by the level of the non-cosmogenic 3He background (i.e., magmatic, radiogenic, nucleogenic, and [...]
Machine learning thermobarometry and chemometry using amphibole and clinopyroxene: a window into the roots of an arc volcano (Mount Liamuiga, Saint Kitts)
Published: 2021-07-04
Subjects: Earth Sciences, Geochemistry, Mineral Physics, Stratigraphy, Volcanology
The physical and chemical properties of magma govern the eruptive style and behaviour of volcanoes. Many of these parameters are linked to the storage pressure and temperature of the erupted magma, and melt chemistry. However, reliable single-phase thermobarometers and chemometers which can recover this information, particularly using amphibole chemistry, remain elusive. We present a suite of [...]
Late Quaternary climatic histories from the Hermes Cave, Corinth Rift, Greece
Published: 2021-06-25
Subjects: Earth Sciences, Geochemistry, Geomorphology, Sedimentology, Speleology
The Greek peninsula is located at the crossroads of several major atmospheric circulation patterns and is consequently characterized by high variability in climatic conditions, making it an important location to examine past climate variability. Over the last decades, the focus of many studies in the region has been to unravel Holocene paleoclimatic oscillations and their impact on the [...]
Environmental variability at the margin of the South American Monsoon System recorded by a high-resolution sediment record from Lagoa Dourada (South Brazil)
Published: 2021-06-25
Subjects: Earth Sciences, Geochemistry, Geomorphology, Sedimentology
High-resolution geochemical and sedimentological data have been obtained for a lacustrine sediment record from Lagoa Dourada (South Brazil). Four distinctly different depositional processes were determined: (1) Suspension fallout of fine-grained minerogenic particles transferred via fluvial activity dominates the Early Holocene and relates to open grassland in the catchment area; (2) Activation [...]
Bayesian population correlation: A probabilistic approach to inferring and comparing population distributions for detrital zircon ages
Published: 2021-06-19
Subjects: Geochemistry, Probability, Statistical Methodology, Tectonics and Structure
Populations of detrital zircons are shaped by geologic factors such as sediment transport, erosion mechanisms, and the zircon fertility of source areas. Zircon U-Pb age datasets are influenced both by these geologic factors and by the statistical effects of sampling. Such statistical effects introduce significant uncertainty into the inference of parent population age distributions from detrital [...]
Geodynamic, geodetic, and seismic constraints favour deflated and dense-cored LLVPs
Published: 2021-06-18
Subjects: Cosmochemistry, Earth Sciences, Geochemistry, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics
Two continent-sized features in the deep mantle, the large low-velocity provinces (LLVPs), influence Earth's supercontinent cycles, mantle plume generation, and its geochemical budget. Seismological advances have steadily improved LLVP imaging, but several fundamental questions remain unanswered, including: What is their vertical extent? And, are they purely thermal anomalies, or are they also [...]
Independent constraints on deep-sea temperatures across two early Eocene hyperthermals from clumped isotope thermometry
Published: 2021-06-08
Subjects: Earth Sciences, Geochemistry
The early Eocene hothouse experienced the occurrence of transient global warming events, so-called hyperthermals. The deep ocean constitutes a stable and vast heat reservoir, and hence arguably provides a good estimate of the global mean climate state. However, available proxy deep-sea temperature reconstructions rely on uncertain assumptions of non-thermal influences associated with seawater [...]
Timing of Martian Core Formation from Models of Hf–W Evolution Coupled with N-body Simulations
Published: 2021-06-04
Subjects: Geochemistry, Mineral Physics, Planetary Sciences
Determining how and when Mars formed has been a long-standing challenge for planetary scientists. The size and orbit of Mars are difficult to reproduce in classical simulations of planetary accretion, and this has inspired models of inner solar system evolution that are tuned to produce Mars-like planets. However, such models are not always coupled to geochemical constraints. Analyses of Martian [...]
Exhuming the Canadian Shield: preliminary interpretations from low-temperature thermochronology and significance for the sedimentary succession of the Hudson Bay Basin
Published: 2021-05-20
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure
The geological history of the Canadian Shield is difficult to constrain because the sedimentary record is missing in those areas where Precambrian basement is exposed at the surface. This study presents preliminary results and interpretations of new apatite fission-track (AFT) analyses to elucidate the low-temperature (< 120 °C) history across Canada. The AFT modelling of samples from Southampton [...]
Chromium evidence for protracted oxygenation during the Paleoproterozoic
Published: 2021-05-18
Subjects: Earth Sciences, Geochemistry, Paleobiology
It has commonly been proposed that the development of complex life—e.g., aerobic eukaryotes—coincided with atmospheric oxygenation. To test this hypothesis, we measured chromium-based oxygen proxies in a >2400-m core from the Onega Basin (NW-Russia), deposited ~2.1–2.0 billion years ago—closely preceding the first eukaryote fossils. Fractionated chromium isotopes are documented throughout the [...]
Nature and timing of anatectic event of the Hida Belt (Japan): Constraints from titanite geochemistry and U-Pb age of clinopyroxene-bearing leucogranite
Published: 2021-05-17
Subjects: Geochemistry, Geology
The Hida Belt, central Japan, is a continental fragment, which was once a part of the crustal basement of the East Asian continental margin. It consists mainly of Permo-Triassic granite-gneiss complexes with both syn-to-late-metamorphic migmatite or granite bodies. Clinopyroxene-bearing leucogranite, locally called as 'Inishi'-type migmatite, occurs characteristically in the migmatite zone [...]
Geochemical signatures of rare earth elements and yttrium in the vicinity of an ion-adsorption type deposit: roles of source sediment control
Published: 2021-05-13
Subjects: Biogeochemistry, Geochemistry, Geology, Hydrology
The elevated concentrations of rare earth elements (REE) and yttrium (REE+Y) in acid mine drainage (AMD) constitute an opportunity for REE+Y recovery. However, the source and control of REE+Y signatures in AMD remains uncertain. Water, rock, sediment and sludge samples were collected from an ion-adsorption rare earth mining area to investigate REE+Y concentration and fractionation patterns in [...]
Primordial and recycled sulfur sampled by the Iceland mantle plume
Published: 2021-05-13
Subjects: Earth Sciences, Geochemistry
Stable sulfur isotope ratios of mid-ocean ridge and ocean island basalts (MORBs and OIBs) preserve unique information about early Earth processes and the long-term volatile cycles between Earth’s mantle and the surface. Icelandic basalts present ideal material to examine the oldest known terrestrial mantle reservoir, accessed through a deep-rooted mantle plume, but their multiple sulfur [...]