Preprints
Filtering by Subject: Geochemistry
The longest-lived Pacific hotspots reveal a plume tail for the largest oceanic plateau
Published: 2023-06-23
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Tectonics and Structure
Volcanic hotspots are thought to initially form by melting in an upwelling mantle plume head followed by melting of the plume tail. Plate motion then generates an age progressive volcanic track originating from a large igneous province that connects to an active hotspot. However, the most voluminous large igneous province, the ~120 Ma Ontong-Java Nui Plateau (OJP-Nui) in the mid-Pacific, appears [...]
Re-evaluating stoichiometric estimates of iron valence in magmatic clinopyroxene crystals
Published: 2023-06-16
Subjects: Geochemistry
Clinopyroxene is a major rock forming mineral capable of incorporating diverse metal cations. As a consequence, clinopyroxene preserves valuable archives of magmatic processes. Understanding clinopyroxene is thus essential for understanding Earth’s wider chemical evolution. However, knowledge about the relative abundances of ferrous and ferric iron in magmatic clinopyroxene remains sparse because [...]
Iron valence systematics in clinopyroxene crystals from ocean island basalts
Published: 2023-06-15
Subjects: Geochemistry
The valence state of Fe plays a vital role in setting and recording the oxidation state of magmas, commonly expressed in terms of oxygen fugacity (fO2 ). However, our knowledge of how and why fO2 varies within and between magmatic systems remains patchy because of diverse challenges associated with estimating the valence state of Fe in glasses and minerals routinely. Here we investigate Fe [...]
Innovating and networking global geochemical data resources through OneGeochemistry
Published: 2023-06-14
Subjects: Biogeochemistry, Cosmochemistry, Databases and Information Systems, Geochemistry, Geology, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Geology, Volcanology
A vision of the not-to-distant future: Imagine yourself as a researcher who is making plans for fieldwork in the Andes Mountains. You are behind your computer and load a three-dimensional visualisation of the Earth and its geology to investigate the research already done in the southern Patagonian regions. You zoom in to the mountain range of interest and select various data layers to show [...]
Carbon Utilization and Storage through Rehabilitation of Groundwater Wells
Published: 2023-05-20
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: 2023-03-25
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 [...]