Preprints

Filtering by Subject: Cosmochemistry

Safety and Belonging in the Field: A Checklist for Educators

Sarah E Greene, Gwen S. Antell, Jake Atterby, et al.

Published: 2021-08-19
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Cosmochemistry, Earth Sciences, Education, Environmental Education, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Environmental Studies, Fresh Water Studies, Geochemistry, Geographic Information Sciences, Geography, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Higher Education, Human Geography, Hydrology, Life Sciences, Meteorology, Mineral Physics, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Nature and Society Relations, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Other Geography, Other Oceanography and Atmospheric Sciences and Meteorology, Other Planetary Sciences, Outdoor Education, Paleobiology, Paleontology, Physical and Environmental Geography, Physical Sciences and Mathematics, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Geology, Planetary Geomorphology, Planetary Geophysics and Seismology, Planetary Glaciology, Planetary Hydrology, Planetary Mineral Physics, Planetary Sciences, Planetary Sedimentology, Remote Sensing, Sedimentology, Social and Behavioral Sciences, Soil Science, Spatial Science, Speleology, Stratigraphy, Sustainability, Tectonics and Structure, Volcanology, Water Resource Management

Ensuring taught fieldwork is a positive, generative, collective, and valuable experience for all participants requires considerations beyond course content. To guarantee safety and belonging, participants’ identities (backgrounds and protected characteristics) must be considered as a part of fieldwork planning and implementation. Furthermore, getting fieldwork right is an important step in [...]

Geodynamic, geodetic, and seismic constraints favour deflated and dense-cored LLVPs

Fred Richards, Mark Hoggard, Siavash Ghelichkhan, et al.

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 [...]

Observational estimates of dynamic topography through space and time

Mark Hoggard, Jacqueline Austermann, Cody Randel, et al.

Published: 2021-01-24
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure, Volcanology

Earth's mantle undergoes convection on million-year timescales as heat is transferred from depth to the surface. Whilst this flow has long been linked to the large-scale horizontal forces that drive plate tectonics and supercontinent cycles, geologists are increasingly recognising the signature of convection through transient vertical motions in the rock record, known as "dynamic topography". A [...]

Jarosite formation in deep Antarctic ice provides a window into acidic, water-limited weathering on Mars

Giovanni Baccolo, Barbara Delmonte, Paul B. Niles, et al.

Published: 2020-05-20
Subjects: Cosmochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Planetary Geochemistry, Planetary Glaciology, Planetary Sciences

Many interpretations have been proposed to explain the presence of jarosite within Martian surficial sediments, including the possibility that it precipitated within paleo-ice deposits owing to englacial weathering of dust. But until now a similar mechanism was not observed on Earth nor in other planetary settings. We report the first multi-analytical indication of jarosite formation within deep [...]

International disparities in open access practices of the Earth Sciences community

Olivier Pourret, David William Hedding, Dasapta Erwin Irawan, et al.

Published: 2020-03-30
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Library and Information Science, Mineral Physics, Other Earth Sciences, Paleobiology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Social and Behavioral Sciences, Soil Science, Speleology, Stratigraphy, Tectonics and Structure, Volcanology

Short communication on international disparities in open access practices of the Earth Sciences community

On the potential of preprints in geochemistry: the good, the bad and the ugly

Olivier Pourret, Dasapta Erwin Irawan, Jonathan Tennant

Published: 2020-03-21
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Library and Information Science, Physical Sciences and Mathematics, Social and Behavioral Sciences

Short communication on the use of preprint in geochemistry

Causation of Late Quaternary Rapid-increase Radiocarbon Anomalies

G. BRAKENRIDGE

Published: 2019-05-07
Subjects: Astrophysics and Astronomy, Cosmochemistry, Earth Sciences, Physical Sciences and Mathematics

Brief (<100 y) rapid-increase anomalies in the Earth’s atmospheric 14C production have previously been attributed to either gamma photon radiation from supernovae or to cosmic ray particle radiation from exceptionally large solar flares. Analysis of distances and ages of nearby supernovae (SNe) remnant surveys, the probable gamma emissions, the predicted Earth-incident radiation, and the [...]

Introduction to Geochronology

Pieter Vermeesch

Published: 2017-12-29
Subjects: Cosmochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics

These lecture notes cover the first half of an Isotope Geology module at University College London that deals with the geochronological aspects of the subject. The notes introduce the basic principles of radioactive decay, mass spectrometry and isotope dilution before discussing the most common geochronometers in use today, including radiocarbon, Rb-Sr, Sm-Nd, U-Pb, Pb-Pb, K-Ar, Ar-Ar, U-Th-He, [...]

Isotopic composition (238U/235U) of some commonly used uranium reference materials

Daniel Condon, Noah McLean, Stephen R Noble, et al.

Published: 2017-11-05
Subjects: Chemistry, Cosmochemistry, Earth Sciences, Geochemistry, Inorganic Chemistry, Physical Sciences and Mathematics

We have determined 238U/235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, and HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U–236U double spike to accurately correct for mass fractionation. Total uncertainty on the 238U/235U determinations is estimated to be <0.02% (2σ). These [...]

238U/235U Systematics in Terrestrial Uranium-Bearing Minerals

Joe Hiess, Daniel Condon, Noah McLean, et al.

Published: 2017-11-05
Subjects: Chemistry, Cosmochemistry, Earth Sciences, Geochemistry, Inorganic Chemistry, Physical Sciences and Mathematics

The present-day 238U/235U ratio has fundamental implications for uranium-lead geochronology and cosmochronology. A value of 137.88 has previously been considered invariant and has been used without uncertainty to calculate terrestrial mineral ages. We report high-precision 238U/235U measurements for a suite of uranium-bearing minerals from 58 samples representing a diverse range of lithologies. [...]

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