Filtering by Subject: Geochemistry

Chemistry speedup in reactive transport simulations: purely data-driven and physics-based surrogates

Marco De Lucia, Michael Kühn

Published: 2020-11-30
Subjects: Earth Sciences, Geochemistry

The computational costs associated with coupled reactive transport simulations are mostly due to the chemical subsystem: replacing it with a pre-trained statistical surrogate is a promising strategy to achieve decisive speedups at price of small accuracy losses and thus to extend the scale of problems which can be handled. We introduce a hierarchical coupling scheme in which ``full [...]

A Vision for the Future Low-Temperature Geochemical Data-scape

Susan L. Brantley, Tao Wen, Deb Agarwal, Jeff Catalano, Paul A. Schroeder, Kerstin Lehnert, Charuleka Varadharajan, Julie Pett-Ridge, Mark Engle, Anthony M. Castronova, Rick Hooper, Xiaogang Ma, Lixin Jin, Kenton McHenry, Emma Aronson, Andrew Shaughnessy, Lou Derry, Justin Richardson, Jerad Bales, Eric Pierce

Published: 2020-11-21
Subjects: Biogeochemistry, Computer Sciences, Databases and Information Systems, Earth Sciences, Environmental Sciences, Geochemistry, Geology, Geomorphology, Hydrology, Other Computer Sciences, Other Earth Sciences, Soil Science

Data sharing benefits the researcher, the scientific community, and most importantly, the public by enabling more impactful analysis of data and greater transparency in scientific research. However, like many other scientists, the low-temperature geochemistry (LTG) community has generally not developed protocols and standards for publishing, citing, and versioning datasets. This paper is the [...]

Boron isotopic signatures of melt inclusions from North Iceland reveal recycled material in the Icelandic mantle source

Margaret Hartley, Oliver Shorttle, Cees-Jan de Hoog

Published: 2020-11-13
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology

Trace element and volatile heterogeneity in the Earth's mantle is inuenced by the recycling of oceanic lithosphere through subduction. Oceanic island basalts commonly have high concentrations of volatiles compared to mid-ocean ridge basalts, but the extent to which this enrichment is linked to recycled mantle domains remains unclear. Boron is an ideal tracer of recycled subducted material, [...]

1600 year-long sedimentary record of tsunamis and hurricanes in the Lesser Antilles (Scrub Island, Anguilla)

Maude BIGUENET, Pierre Sabatier, Eric Chaumillon, Catherine Chagué, Fabien Arnaud, Frans Jorissen, Thibault Coulombier, Emeline Geba, Louise Cordrie, Pierre Vacher, Anne-Lise Develle, Emilie Chalmin, Fayçal Soufi, Nathalie Feuillet

Published: 2020-10-22
Subjects: Geochemistry, Oceanography, Sedimentology

The Lesser Antilles are a densely populated and a very touristic region exposed to many short-term hazards such as hurricanes and tsunamis. However, the historical catalog of these events is too short to allow risk assessment and return period estimations, and it needs to be completed with long-term geological records. Two sediment cores were sampled in March 2018 in a small coastal lagoon on [...]

Modulation of riverine concentration-discharge relationships by changes in the shape of the water transit time distribution

Mark Albert Torres, J. Jotautas Baronas

Published: 2020-10-21
Subjects: Geochemistry, Hydrology

The concentrations of weathering-derived solutes in rivers and their co-variance with discharge are thought to reflect reactive-transport processes in hillslopes and to reveal the sensitivity of solute fluxes to climatic change. It is expected that discharge-driven changes in water transit times play some role in setting concentration-discharge (C-Q) relationships, but knowledge gaps remain. To [...]

The global melt inclusion C/Ba array: mantle variability, melting process, or degassing?

Simon Matthews, Oliver Shorttle, John Maclennan, John F Rudge

Published: 2020-10-21
Subjects: Earth Sciences, Geochemistry

The Earth’s mantle holds more carbon than its oceans, atmosphere and continents combined, yet the distribution of carbon within the mantle remains uncertain. Our best constraints on the distribution of carbon within the upper mantle are derived from the carbon-trace element systematics of ultra-depleted glasses and melt inclusions from mid-ocean ridge basalts. However, carbon-trace element [...]

Dynamics of core-mantle separation: influence of viscosity contrast and metal/silicate partition coefficients on the chemical equilibrium

Vincent Clesi, Julien Monteux, Baraa Qaddah, Michael Le Bars, Jean-Baptiste Wacheul, Mohamed Ali Bouhifd

Published: 2020-10-21
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Physical Sciences and Mathematics

The composition of the Earth's core and mantle is set by the chemical equilibrium between metals and silicates during core/mantle segregation. The metallic core separated from the mantle by gravitational descent in the form of diapirs in a magma ocean, and therefore the dynamics of the diapir's downward movement has an influence on the chemical equilibrium. In this study, we characterize the [...]

Global Systematics of Copper in Arc Magmas: A Big Data Approach

Nicholas Dewitt Barber, Marie Edmonds, Frances Jenner, Andreas Audétat, Helen Williams

Published: 2020-10-21
Subjects: Earth Sciences, Geochemistry, Geology, Volcanology

Copper, sourced from porphyry deposits formed in arc settings, is an increasingly scarce yet critical resource. The processes that shape the copper contents of magmas remain poorly understood. One theory is that magmas must be copper-rich in order to form porphyry deposits. Mature arcs have up to now played an outsized role in shaping existing models of copper systematics in magmas. Here we take [...]

A machine learning approach for prioritizing groundwater testing for per-and polyfluoroalkyl substances (PFAS)

Sarabeth George, Atray Dixit

Published: 2020-10-19
Subjects: Environmental Engineering, Environmental Health and Protection, Environmental Monitoring, Geochemistry, Hydrology, Risk Analysis, Water Resource Management

Regulatory agencies are beginning to recognize per-and polyfluoroalkyl substances (PFAS) as concerning and bioaccumulative compounds of which the use and environmental burden must be reduced. In the specific context of groundwater management, testing and mitigation strategies are desirable but can be time and cost-intensive processes. As a result, only a fraction of all groundwater wells has had [...]

The composition and weathering of the continents over geologic time

Alex Lipp, Oliver Shorttle, Erik Sperling, Jochen J Brocks, Devon Cole, Peter Crockford, Lucas Del Mouro, Keith Dewing, Stephen Q Dornbos, Joseph F. Emmings

Published: 2020-08-21
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics

The composition of continental crust records a history of construction by tectonics and destruction by physical and chemical erosion. Quantitative constraints on how both igneous addition and chemical weathering have modified the continents bulk composition are essential for understanding the evolution of geodynamics and climate. We have extracted temporal trends in sediments protolith [...]

Apatite fission-track dating by LA-Q-ICP-MS mapping

Claire Ansberque, David Chew, Kerstin Drost

Published: 2020-08-17
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics

Obtaining accurate and precise apatite fission-track (AFT) ages is dependent on producing plentiful high-quality apatite grains from a sample, ideally with high spontaneous fission-track densities (c. >105 Many natural samples, such as bedrock samples from young orogenic belts or low-grade metamorphic samples with low U contents yield low spontaneous fission-track densities. Such [...]

Marine mineral-catalyzed NO and N2O formation on the anoxic early Earth

Steffen Buessecker, Hiroshi Imanaka, Tucker Ely, Renyu Hu, Stephen J. Romaniello, Hinsby Cadillo-Quiroz

Published: 2020-08-16
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics

Microbial metabolisms were limited by available terminal electron acceptors in the anoxic environment of the early Archean. However, iron mineral phases in Fe2+-rich (ferruginous) oceans could have catalyzed reactions with abiotically fixed nitrogen leading to the formation of nitrous oxide (N2O), a potentially favorable terminal electron acceptor. We experimentally simulated anoxic [...]

Hydrogeologic and Geochemical Distinctions in Salar Freshwater Brine Systems

Lee Ann Munk, David Boutt, Brendan J. Moran, Sarah McKnight, Jordan Jenckes

Published: 2020-08-05
Subjects: Earth Sciences, Geochemistry, Hydrology, Physical Sciences and Mathematics

The Salar de Atacama contains one of the world’s most important lithium resources and hosts unique and fragile desert ecosystems. Water use issues of the hyper-arid region have placed it at the center of global attention. This investigation is the first robust assessment of a salar system to incorporate geology, hydrogeology, and geochemistry of the aquifer system in the inflow, transition zone [...]

Whats down there? The structures, materials and environment of deep-seated tremor and slip

Whitney Maria Behr, Roland Bürgmann

Published: 2020-07-16
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Episodic tremor and slow slip (ETS) events occur downdip of the seismogenic zone of numerous subduction megathrusts and plate boundary strike-slip faults. These events represent a fascinating and perplexing mode of fault failure that has greatly broadened our view of earthquake dynamics. In this contribution, we review constraints on the ETS deformation process from both geophysical observations [...]

Fingerprinting fluid source in calcite veins: combining LA-ICP-MS U-Pb calcite dating with trace elements and clumped isotope palaeothermometry

John MacDonald, Jacob Van Der Wal, John Faithfull, Adrian Boyce, Nick Roberts, Ian Winkelstern

Published: 2020-07-15
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics

Application of geochemical proxies to vein minerals - particularly calcite - can fingerprint the source of fluids controlling various important geological processes from seismicity to geothermal systems. Determining fluid source, e.g. meteoric, marine, magmatic or metamorphic waters, can be challenging when using only trace elements and stable isotopes as different fluids can have overlapping [...]


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