Preprints
Filtering by Subject: Geochemistry
Carbon Utilization and Storage through Rehabilitation of Groundwater Wells
Published: 2023-05-21
Subjects: Applied Statistics, Civil and Environmental Engineering, Climate, Earth Sciences, Environmental Sciences, Geochemistry, Hydrology, Longitudinal Data Analysis and Time Series, Oil, Gas, and Energy, Statistical Methodology, Statistical Models, Statistics and Probability
According to the Intergovernmental Panel on Climate Change (IPCC) of the United Nations (UN), rise in atmospheric concentration of carbon dioxide (CO2) due to anthropogenic factors is considered as the primary driver for global climate change. With almost every major corporation around the world working towards their “net-zero goals”, it is becoming increasingly important to have more [...]
Bioavailable Sr and Pb isotope ratios of archaeological cattle bone from coastal India
Published: 2023-04-28
Subjects: Biogeochemistry, Geochemistry
We present the first measurement of bioavailable strontium (87Sr/86Sr) and lead (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb) isotope ratios from five cattle bones and one soil sample from Erenda, a chalcolithic site in coastal east India. Bioavailable 87Sr/86Sr of bones differ from that of the soil. A similar Pb isotope ratio of bones to the soil indicates an insignificant diagenesis and local [...]
A key role for diffusion creep in eclogites: Omphacite deformation in the Zermatt-Saas Unit, Italian Alps
Published: 2023-04-18
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Tectonics and Structure
Eclogites are important components of subduction-collision zones, with the mineral omphacite acting as the supporting framework mineral that accommodates the majority of any accumulated strain. As such it is important to determine which deformation mechanisms operate in omphacite during and after its formation to understand the rheology of deforming subducted crust. Such information is key to [...]
Linking the core heat content to Earth's accretion history
Published: 2023-03-26
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Planetary Geochemistry, Planetary Geophysics and Seismology
In this study we use a parameterized model of differentiation in a magma ocean setting, in which the magma ocean depth evolves during accretion, to predict the composition of the primordial core. We couple this chemical model to a thermal evolution model of the accreting metal to estimate the Earth's core heat content at the end of its formation. We find geochemically consistent models. All these [...]
Single Column REE Separation and Radiogenic 143Nd/144Nd Analysis without Sm Elimination
Published: 2023-03-10
Subjects: Analytical Chemistry, Geochemistry
A single column separation method has been developed for the determination of radiogenic 143Nd/144Nd ratios for natural geological samples. Conventional radiogenic Nd isotope ratio measurements require rigorous column chemistry involving multiple steps to extract a pure Nd fraction. Elements that cause isobaric interference during analysis are removed using a multi-column separation method, which [...]
Steady decline in mean annual air temperatures in the first 30 ka after the Cretaceous-Paleogene boundary
Published: 2023-03-06
Subjects: Climate, Earth Sciences, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Stratigraphy
The Cretaceous-Paleogene (K-Pg) boundary marks one of the five major mass extinctions of the Phanerozoic. How the climate system responded to a bolide impact and extensive volcanism at this time over different timescales is highly debated. Here we use the distribution of branched tetraether lipids (brGDGT) from fossil peats at two sites in Saskatchewan, Canada (paleolatitude ~55°N), to generate a [...]
The applicability of G-BASE stream sediment geochemistry as a combined geological mapping, and prospective exploration tool for As-Co-Cu-Ni mineralisation across Cumbria, UK.
Published: 2023-01-18
Subjects: Earth Sciences, Geochemistry, Geology, Multivariate Analysis, Physical Sciences and Mathematics, Statistics and Probability
Stream sediment geochemistry is a useful tool to analyse the geochemistry of the local geology within the source catchment area. This has significant applicability within the field of mineral exploration where understanding regional lithological geochemistry is needed, facilitating the identification of critical metal deposits. Successful identification of these deposits is essential to help [...]
A multi-siderophile element connection between volcanic hotspots and Earth’s core
Published: 2023-01-18
Subjects: Geochemistry
The existence of resolvable 182W/184W deficits in modern ocean island basalts (OIB) relative to the bulk silicate Earth has raised questions about the relationship of these rocks to Earth’s core. However, because the core is expected to host high abundances of highly siderophile elements (HSE), it would be expected that such heterogeneity is accompanied by correlating variability in HSE [...]
Diffusion of halogens (F, Cl, Br, I) in silicic melt
Published: 2023-01-10
Subjects: Earth Sciences, Geochemistry, Volcanology
Chemical diffusion of the halogens F, Cl, Br, and I in silica-rich natural melts was experimentally investigated by the diffusion couple technique. Experiments were conducted under anhydrous conditions at atmospheric pressure and hydrous conditions (~1.5 wt.% H2O) at 160 MPa, over a temperature range of 750–1000 °C and 1000–1200 °C, respectively. Quenched trachytic melt samples were analyzed [...]
Are marl-limestone alternations mainly driven by CaCO3 variations at the astronomical timescale? New insights from extraterrestrial 3He
Published: 2023-01-07
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Sedimentology, Stratigraphy
Marl-limestone alternations are rhythmical inter-bedded deposits that commonly occur in many sedimentological environments. It is quite well established that these lithological variations originate from astronomically-driven climatic variations paced by the Milankovitch cycles of main periods 19, 23, 41, 100 and 405 ka. However, the sedimentological mechanisms involved are not clear: some models [...]
Tracing timing of growth in cultured mollusks using strontium spiking
Published: 2022-12-23
Subjects: Aquaculture and Fisheries Life Sciences, Biogeochemistry, Geochemistry, Paleontology
Growth experiments present a powerful tool for determining the effect of environmental parameters on growth and carbonate composition in biogenic calcifiers. For successful proxy calibration and biomineralization studies, it is vital to exactly identify volumes of carbonate precipitated at precise intervals during the experiment. Here, we investigate the use of strontium labelling in mollusk [...]
Oxidation Rates and Redox Stabilization of Ferrous Iron in Trioctahedral Smectites
Published: 2022-12-16
Subjects: Biogeochemistry, Geochemistry, Other Earth Sciences, Planetary Biogeochemistry, Planetary Geochemistry
Iron(II)-bearing trioctahedral smectites (saponites) form during anoxic alteration of basaltic rock. They are predicted to have been widespread on the early Earth and are observed in the oceanic subsurface today. Smectite structures, including the occupancy of sites in the octahedral sheet, affect iron redox behavior but the rates and products of trioctahedral smectite oxidation have been largely [...]
Barometers behaving badly II: A critical evaluation of Cpx-only and Cpx-Liq thermobarometry in variably-hydrous arc magmas
Published: 2022-12-14
Subjects: Earth Sciences, Geochemistry, Geology, Volcanology
The chemistry of erupted clinopyroxene crystals (±equilibrium liquids) have been widely used to deduce the pressures and temperatures of magma storage in volcanic arcs. However, the large number of different equations parametrizing the relationship between mineral and melt compositions and intensive variables such as pressure and temperature yield vastly different results, with implications for [...]
Barometers behaving badly: Assessing the influence of analytical and experimental uncertainty on clinopyroxene thermobarometry calculations at crustal conditions
Published: 2022-12-01
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Volcanology
The composition of clinopyroxene and Clinopyroxene-Liquid (Cpx-Liq) pairs are frequently used to calculate crystallization/equilibration pressures in igneous systems. While canonical uncertainties are often assigned to calculated pressures based on fits to calibration or test datasets, the sources of these uncertainties (and thus ways to reduce them) have not been rigorously assessed. We show [...]
Lithospheric structure and melting processes in southeast Australia: new constraints from joint probabilistic inversions of 3D magnetotelluric and seismic data
Published: 2022-11-18
Subjects: Geochemistry, Geophysics and Seismology, Volcanology
The thermochemical structure of the lithosphere exerts control on melting mechanisms in the mantle as well as the location of volcanism and ore deposits. Imaging the complex interactions between the lithosphere and asthenospheric mantle requires the joint inversion of multiple data sets and their uncertainties. In particular, the combination of seismic velocity and electrical conductivity with [...]