Preprints
Filtering by Subject: Geochemistry
Competitive and Cooperative Effects of Chloride on Palladium(II) Adsorption to Iron (Oxyhydr)oxides: Implications for Mobility During Weathering
Published: 2024-09-10
Subjects: Geochemistry
In surface and near-surface weathering environments, the mobilization and partial loss of palladium (Pd) under oxidizing and weakly acidic conditions has been attributed to aqueous chloride complexation. However, prior work has also observed that a portion of Pd is retained by iron (oxyhydr)oxides in the weathering zone. The effect chloride has on the relative amount of Pd mobilization versus [...]
Evidence supporting a broader than previously thought influence of solar activity over Earth system’s processes. Discussion of a possible mechanism.
Published: 2024-09-08
Subjects: Atmospheric Sciences, Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Tectonics and Structure, Volcanology
In this article, I show lines of evidence supporting a modulation of volcanic activity and some weather phenomena by solar wind conditions in the near-Earth environment. On a daily timescale, a correlation is found between the LP earthquake activity of Kilauea volcano, related to magma transport, and the Bx component of the interplanetary magnetic field as measured in the OMNI database for [...]
Critical Review of the Article: "Evidence of Dark Oxygen Production at the Abyssal Seafloor" by Sweetman et al. in Nat. Geosci. 1–3 (2024)
Published: 2024-08-12
Subjects: Geochemistry
This review examines the findings and methodologies presented in Sweetman et al. (2024) (hereafter referred to as ‘the paper’). The paper presents findings contrasting those of all previous comparable work and has stirred international debate pertaining to deep-sea minerals. We identify significant issues in data collection, validation, and interpretation including unvalidated data collection [...]
Alteration processes of mantle peridotite in the Samail ophiolite inferred from independent component analysis of rock physical properties
Published: 2024-07-27
Subjects: Geochemistry, Mineral Physics, Multivariate Analysis
To quantify the alteration processes of mantle from geophysical data, an understanding of the relationship between alteration and the physical properties of mantle peridotite is essential. In this study, we employed independent component analysis (ICA) to evaluate variations in the physical properties of altered peridotites collected by the Oman Drilling Project, to understand the alteration [...]
Volcanic arc structure controlled by liquid focusing from the slab — evidence from boron isotopes and trace elements
Published: 2024-07-16
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology
The rates and pathways of material transport from subducting plates to arc volcanoes control the long-term chemical evolution of the atmosphere, continents, and mantle. Arc magma compositions are commonly used as proxies for the state of the slab directly below a volcanic vent, under the assumption of vertical transport from the slab to the surface. Here, we present new boron (B) isotope and [...]
Seamounts control subducted carbonate recycling in Central America – evidence from stable Sr isotopes
Published: 2024-07-13
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology
Accurate estimates of carbon recycling efficiency at subduction zones are crucial for understanding the long-term evolution of the planet’s climate. Estimating subducting carbon recycling efficiency is difficult, however, due to magmatic degassing deep within the crust. Stable strontium (δ88Sr) isotopes have the potential to serve as an additional proxy for carbonate recycling due to carbonate’s [...]
Interdiffusion of major elements at 1 atmosphere between natural shoshonitic and rhyolitic melts
Published: 2024-07-12
Subjects: Earth Sciences, Geochemistry, Volcanology
The diffusive mass exchange of eight major elements (Si, Ti, Al, Fe, Mg, Ca, Na, and K) between natural, nominally dry shoshonitic and rhyolitic melts was studied at atmospheric pressure and temperatures between 1230 and 1413 °C using the diffusion couple method. For six elements, effective binary diffusion coefficients were calculated by means of a concentration-dependent method to obtain an [...]
Pre-Cordilleran mantle metasomatism preserved in alkali basalts of Isla Isabel, México
Published: 2024-07-10
Subjects: Geochemistry, Geology
The presence of HIMU (high-238U/204Pb) signatures in ocean island basalts has long been used to argue that ancient oceanic crust has been tectonically recycled into the mantle sources of plume-derived volcanic hotspots such as St. Helena or Mangaia. However, alternative hypotheses regarding the origins of HIMU signatures have also been put forward. This paper addresses the origins of HIMU-like Pb [...]
Uranium-series isotopes as tracers of physical and chemical weathering in glacial sediments from Taylor Valley, Antarctica
Published: 2024-07-04
Subjects: Earth Sciences, Geochemistry, Glaciology, Soil Science
The McMurdo Dry Valleys of Antarctica formed by extensive glacial erosion, yet currently exhibit hyperarid polar conditions characterized by limited chemical and physical weathering. Efficient chemical weathering occurs when moisture is available, and polythermal subglacial conditions may accommodate ongoing mechanical weathering and valley incision. Taylor Valley hosts several Pleistocene [...]
Shallow storage conditions at Krafla IDDP-1 revealed by rhyolite-MELTS geobarometry, and implications for global shallow magmatism
Published: 2024-06-24
Subjects: Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Volcanology
Identifying the storage depths of melt-dominated magma bodies prior to eruption is critical for understanding magma transport, eruption hazards, and magma body longevity. Rhyolite-MELTS has been used effectively to calculate pre-eruptive storage pressures for silicic magma bodies in the upper crust (~100-350 MPa), but its precision and accuracy in very low-pressure systems (<100 MPa) has not [...]
Diversity at Goldschmidt conference
Published: 2024-06-19
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Sciences
The field of geochemistry has grown significantly over the past seventy years, contributing to our understanding of Earth's processes. However, geochemists often identify with broader fields like geology or oceanography, reflecting an identity crisis within the discipline. The Goldschmidt Conference, established in 1988, serves as a central international meeting for geochemists, promoting their [...]
Mercury records from natural archives reveal ecosystem responses to changing atmospheric deposition
Published: 2024-05-15
Subjects: Atmospheric Sciences, Environmental Sciences, Geochemistry, Geography, Physical and Environmental Geography
Global ecosystems face mercury contamination, yet long-term data is scarce, hindering understanding of ecosystem responses to atmospheric Hg input changes. To bridge data gap and assess ecosystem responses, we compiled and compared a mercury accumulation database from peat, lake, ice, and marine deposits worldwide with atmospheric mercury deposition modeled by GEOS-Chem, focusing on trends, [...]
Carbonate clumped isotope values compromised by nitrate-derived NO2 interferent
Published: 2024-04-30
Subjects: Earth Sciences, Geochemistry
∆47 based clumped isotope thermometry has enabled reconstruction of Earth’s surface temperatures independent of the source of oxygen within the carbonate. It has been postulated that carbonate samples can contain contaminants that cause isobaric interferences, compromising measured ∆47 values and reconstructed temperatures. The exact nature of contaminants and isobaric interferents, however, [...]
High–precision determination of carbon stable isotope in silicate glasses by secondary ion mass spectrometry: Evaluation of international standards
Published: 2024-04-24
Subjects: Analytical Chemistry, Geochemistry
Secondary ion mass spectrometry (SIMS) has been used for isotope analysis of volatile components dissolved in silicate melts for decades. However, carbon in situ stable isotope analysis in natural silicate glasses has remained particularly challenging, with the few published attempts yielding high uncertainties. In this context, we characterized 31 reference silicate glasses of basaltic and [...]
Limited long-term cooling effects of flood basalt emplacements
Published: 2024-04-23
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Volcanology
The emplacement of large igneous provinces (LIPs) is known to have been a driver of climate change in Earth’s past, particularly during the breakup of Pangaea. However, the balance between climate warming through CO2 emission and climate cooling through increased weathering is poorly understood. To better understand the role of LIP emplacement on long-term climate change, we utilize a coupled [...]