Preprints
Filtering by Subject: Geochemistry
Sampling across large-scale geological gradients to study geosphere-biosphere interactions
Published: 2022-07-25
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Geochemistry, Life Sciences, Microbiology
Despite being one of the largest microbial ecosystems on Earth, with >1029 microbial cells, many basic open questions remain about how life exists and thrives in the deep subsurface biosphere, inside Earth’s crust. Much of this ambiguity is due to the fact that it is exceedingly difficult and (often prohibitively expensive) to directly sample the deep subsurface, requiring elaborate drilling [...]
Evaluation of preservation protocols for oxygen-sensitive minerals within laminated aquatic sediments
Published: 2022-07-25
Subjects: Biogeochemistry, Environmental Sciences, Geochemistry, Sedimentology
Laminated sediments can record seasonal changes in sedimentation of material from anoxic waters, including minerals of the redox-sensitive elements Fe, Mn, and S that form under varying oxygen levels, mineral saturation conditions, and from microbial metabolism. However, preserving both the oxygen-sensitive minerals for identification is challenging when preservation of the spatial arrangement of [...]
Slab to back-arc to arc: fluid and melt pathways through the mantle wedge beneath the Lesser Antilles
Published: 2022-07-14
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Tectonics and Structure, Volcanology
Volatiles expelled from subducted plates melt the overlying warm mantle, feeding arc volcanism. However, debates continue over the factors controlling melt generation and transport and how these determine the placement of volcanoes. To broaden our synoptic view of these fundamental mantle wedge processes, we image seismic attenuation beneath the Lesser Antilles arc, an end-member system that [...]
Barren ground depressions, natural H2 and orogenic gold deposits: spatial link and geochemical model
Published: 2022-07-11
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Geochemistry, Geology, Geomorphology, Soil Science
A review of the localities in continental rocks where H2-rich gases have been reported, showed that they are mainly located near gold deposits. Two types of geomorphological features known as markers of gas venting in sedimentary basins were also systematically observed near orogenic gold deposits on satellite images. They consist in both barren ground depressions and high densities of small (< [...]
Evolution of diversity in the editorial boards of Geochimica et Cosmochimica Acta and Chemical Geology
Published: 2022-06-24
Subjects: Geochemistry, Physical Sciences and Mathematics
Background: Editorial board members of academic journals are often considered gatekeepers of knowledge and role models for the community. Editorial boards should have sufficiently diverse backgrounds to facilitate the publication of manuscripts with a wide range of research paradigms, methods, and cultural perspectives. Objectives: This study critically evaluates changes in the representation of [...]
Pervasive carbonation of peridotite to listvenite (Semail Ophiolite, Sultanate of Oman): clues from iron partitioning and chemical zoning
Published: 2022-06-21
Subjects: Geochemistry, Geology
Earth’s long-term cycling of carbon is regulated from mid-ocean ridges to convergent margins by mass transfers involving mantle rocks. Here we examine the conversion of peridotite into listvenite (magnesite+quartz) occurring along the basal thrust of the Semail Ophiolite (Fanja, Sultanate of Oman). At the outcrop scale, this transformation defines reaction fronts, from serpentinized peridotites, [...]
Validation of glacial-interglacial rainfall variations in southwest Sulawesi using Mg/Ca and δ18O in speleothems
Published: 2022-06-17
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Geochemistry, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Speleology
The final version of this article is now published with Communications. Earth and Environment. To view this open access article, please use the Published Article DOI. Speleothem δ18O is widely used as a proxy for rainfall amount in the tropics on glacial-interglacial to interannual scales. However, uncertainties in the interpretation of this renowned proxy pose a vexing problem in tropical [...]
The historical impact of anthropogenic air-borne sulphur on the Pleistocene rock art of Sulawesi
Published: 2022-05-31
Subjects: Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Sciences, Geochemistry, Natural Resources and Conservation
The Maros-Pangkep karst in southwest Sulawesi, Indonesia, contains some of the world’s oldest rock art. However, the Pleistocene images survive only as weathered patches of pigment on exfoliated limestone surfaces. Salt efflorescence underneath the case-hardened limestone substrate causes spall-flaking, and it has been proposed that the loss of artwork has accelerated over recent decades. Here, [...]
Paleoclimate controls on lithium enrichment in Great Basin Pliocene-Pleistocene lacustrine clays
Published: 2022-05-29
Subjects: Climate, Earth Sciences, Environmental Sciences, Geochemistry, Geology, Natural Resources and Conservation, Other Environmental Sciences, Sedimentology
Terminal lakes are important archives of continental hydroclimate and in some cases contain important economic resources. Here, we present an ∼2.9 m.y. lacustrine carbonate carbon and oxygen stable isotope record from a Great Basin continental drill core. We paired these measurements with bulk lithium concentrations to reveal a relationship between past climate and lithium enrichment in [...]
A very unconventional hydrocarbon play: the Mesoproterozoic Velkerri Formation of Northern Australia
Published: 2022-05-16
Subjects: Geochemistry, Geology, Sedimentology, Stratigraphy, Tectonics and Structure
The ca. 1.5–1.3 Ga Roper Group of the greater McArthur Basin is a component of one of the most extensive Precambrian hydrocarbon-bearing basins preserved in the geological record, recently assessed as containing 429 million barrels of oil and eight trillion cubic feet of gas (in place). It was deposited in an intra-cratonic sea, referred to here as the McArthur-Yanliao Gulf. The Velkerri [...]
Quantifying excess heavy metal concentrations in drainage basins using conservative mixing models
Published: 2022-05-13
Subjects: Earth Sciences, Environmental Sciences, Geochemistry, Geomorphology, Physical Sciences and Mathematics, Sustainability, Water Resource Management
High concentrations of heavy metals and other pollutants in river sediments can have detrimental effects on the ecosystem and humans. The composition of river sediments throughout drainage basins therefore provides important information for environmental monitoring. An obvious first step for using river sediment compositions for monitoring is to quantify natural baseline concentrations. Once [...]
The CREp 36Cl exposure age calculator: development version “dev”
Published: 2022-05-04
Subjects: Geochemistry, Geology, Geomorphology, Glaciology, Sedimentology, Tectonics and Structure, Volcanology
Chlorine-36 (36Cl) is currently the only in situ cosmogenic nuclide applicable in carbonates, Ca- and K-rich feldspars and aphyric silicate rocks. Because the production reactions of 36Cl are more numerous and complex than those of other cosmogenic nuclides (e.g. 10Be, 3He), comprehensive and user-friendly calculators are essential for routine application of 36Cl to Earth surface research [...]
Radiogenic isotope: not just about words
Published: 2022-04-30
Subjects: Earth Sciences, Geochemistry
This viewpoint is a short comment on gender issues with isotope terminology. The terms "parent"/"daughter" should be avoided in favor of the more descriptive "precursor ion" and "product ion" terms.
Expansion and intensification of the North American Monsoon during the Pliocene
Published: 2022-04-14
Subjects: Climate, Earth Sciences, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology
Southwestern North America, like many subtropical regions, is predicted to become drier in response to anthropogenic warming. However, during the Pliocene, when carbon dioxide was above pre-industrial levels, multiple lines of evidence suggest that southwestern North America was much wetter. While existing explanations for a wet Pliocene invoke increases in winter rain, recent modeling studies [...]
Late Glacial and Holocene Palaeolake History of the Última Esperanza Region of Southern Patagonia
Published: 2022-03-29
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Glaciology, Hydrology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology
We undertook multiproxy analyses on two sediment cores from Lago Pato, a small lake basin at 51°S topographically separated from Lago del Toro in Torres del Paine (TdP), to provide insights into glacier dynamics and lake level change in the TdP and Última Esperanza region over the last ~30,000 cal a BP (30 ka). Lago Pato is situated in a region overridden by the Southern Patagonian Icefield [...]