Preprints

There are 2478 Preprints listed.

Thrusts control the thermal maturity of accreted sediments

Utsav Mannu, David Fernández-Blanco, Ayumu Miyakawa, et al.

Published: 2021-09-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Thermal maturity assessments of hydrocarbon-generation potential and thermal history rarely consider how structures developing during subduction influence the trajectories of accreted sediments. Our thermomechanical models of subduction support that thrusts evolving under variable sedimentation rates and décollement strengths fundamentally influence the trajectory, temperature, and thermal [...]

The ‘europium anomaly’ in plants: facts and fiction

Olivier Pourret, Antony van der Ent, Andrew Hursthouse, et al.

Published: 2021-09-08
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Life Sciences, Plant Sciences

Rare earth elements (REEs) and normalized REE pattern determined in plant and soil samples represent powerful tools to trace biogeochemical processes during weathering, soil genesis and processes in the rhizosphere, and thus publications reporting rare earth elements and normalized REE pattern in soil systems and plants are increasing rapidly. Generally, a normalized REE pattern allow for the [...]

Higher Long-Term Soil Moisture Increases Organic Carbon Accrual Through Microbial Conversion of Organic Inputs

Itamar Shabtai, Srabani Das, Thiago Inagaki, et al.

Published: 2021-09-08
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics

High long-term soil moisture may either stimulate or inhibit soil organic carbon (SOC) losses through changes to mineral and chemical composition, and resultant organo-mineral interactions. Yet, the trade-off between mineralization and accrual of SOC under long-term variation in unsaturated soil moisture remains an uncertainty. In this study, we tested the underexplored relationships between [...]

Changes in poleward atmospheric energy transport over a wide range of climates: Energetic and diffusive perspectives and a priori theories

Timothy M Merlis, Nicole Feldl, Rodrigo Caballero

Published: 2021-09-07
Subjects: Oceanography and Atmospheric Sciences and Meteorology

The midlatitude poleward atmospheric energy transport increases in radiatively forced simulations of warmed climates across a range of models from comprehensive coupled general circulation models (GCMs) to idealized aquaplanet moist GCMs to diffusive moist energy balance models. These increases have been rationalized from two perspectives. The energetic (or radiative) perspective takes the [...]

Interannual variability in methane and nitrous oxide concentrations and sea-air fluxes across the North American Arctic Ocean (2015–2019)

Cara Manning, Zhiyin Zheng, Lindsay Fenwick, et al.

Published: 2021-09-07
Subjects: Physical Sciences and Mathematics

Between 2015–2018, we collected ~2000 measurements of methane (CH4) and nitrous oxide (N2O) concentrations in the North American Arctic Ocean during summer and early fall from water column profiles. We also obtained 25 measurements of CH4 and N2O concentrations in rivers along the Northwest Passage and Ellesmere Island in mid-summer 2017–2019. Our results show that N2O is generated in the highly [...]

Assessment pebble virtual velocity from combined active RFID fixed stations and geophones

Mathieu Cassel, Hervé Piégay, Oldrich Navratil, et al.

Published: 2021-09-06
Subjects: Geomorphology, Geophysics and Seismology, Hydrology

The monitoring of coarse sediment transport is a domain teeming with technical innovations and methodological developments aimed at improving the characterization of bedload processes at different spatial and temporal scales. Radio frequency identification (RFID) technology has improved sediment tracking experiments, allowing the characterization of processes at the individual particle and [...]

High interstadial sea levels over the past 420ka from Huon terraces (Papua New Guinea)

Gino de Gelder, Laurent Husson, Anne-Morwenn Pastier, et al.

Published: 2021-09-06
Subjects: Climate, Geology, Geomorphology, Oceanography, Tectonics and Structure

The history of sea level across the Quaternary is essential for assessing past and future climate and geodynamics. Global sea-level reconstructions are typically derived from oxygen isotope curves, but require calibration with geological constraints that are particularly scarce prior to the last glacial cycle (>130 ka). The exceptionally well-preserved coral reef terrace sequence in the Huon [...]

Drone-mounted GPR surveying: flight-height considerations for diffraction-based velocity analysis

Adam Booth, Tiffany Koylass

Published: 2021-09-06
Subjects: Earth Sciences, Geophysics and Seismology, Other Earth Sciences

Recent studies highlight the potential of the drone platform for ground penetrating radar (GPR) surveying. Most guidance for optimising drone flight-heights is based on maximising the image quality of target responses, but no study yet considers the impact on diffraction travel-times. Strong GPR velocity contrasts across the air-ground interface introduce significant refraction effects that [...]

Lowermost mantle shear-velocity structure from hierarchical trans-dimensional Bayesian tomography

Sima Mousavi, Hrvoje Tkalčić, Rhys Hawkins, et al.

Published: 2021-09-05
Subjects: Earth Sciences, Physical Sciences and Mathematics

The core-mantle boundary (CMB) is the most extreme boundary within the Earth where the liquid, iron-rich outer core interacts with the rocky, silicate mantle. The nature of the lowermost mantle atop the CMB, and its role in mantle dynamics, is not completely understood. Various regional studies have documented significant heterogeneities at different spatial scales. While there is a consensus on [...]

Recharge observations indicate strengthened groundwater connection to surface fluxes

Wouter Berghuijs, Elco Luijendijk, Christian Moeck, et al.

Published: 2021-09-03
Subjects: Physical Sciences and Mathematics

Groundwater is an invaluable global resource, but its long-term viability as a resource for consumption, agriculture, and ecosystems depends on precipitation recharging aquifers. How much precipitation recharges groundwaters varies enormously across Earth's surface, but recharge rates are uncertain because field observations are sparse and modeled global estimates remain largely unvalidated. Here [...]

CCREM: New reference Earth model from the global coda-correlation wavefield

Xiaolong Ma, Hrvoje Tkalčić

Published: 2021-09-02
Subjects: Earth Sciences, Physical Sciences and Mathematics

The existing Earth reference models have provided an excellent one-dimensional representation of Earth’s properties as a function of its radius and explained many seismic observations in a broad frequency band. However, some discrepancies still exist among these models near the first-order discontinuities (e.g., the core-mantle and the inner-core boundaries) due to different datasets and [...]

Assessing pyrite-derived sulfate in the Mississippi River with four years of sulfur and triple-oxygen isotope data

Bryan Killingsworth, Huiming Bao, Issaku Kohl

Published: 2021-09-02
Subjects: Geochemistry

Riverine dissolved sulfate (SO42−) sulfur and oxygen isotope variations reflect their controls such as SO42− reduction and re-oxidation, and source mixing. However, unconstrained temporal variability of riverine SO42− isotope compositions due to short sampling durations may lead to mischaracterization of SO42− sources, particularly for the pyrite-derived sulfate load. We measured the sulfur and [...]

Worldwide moderate-resolution mapping of lake surface chl-a reveals variable responses to global change (1997-2020)

Benjamin M Kraemer, Karan Kakouei, Catalina Munteanu, et al.

Published: 2021-09-01
Subjects: Fresh Water Studies

Anthropogenic activity is leading to widespread changes in lake water quality--a key contributor to socio-ecological health. But, the anthropogenic forces affecting lake water quality (climate change, land use change, and invasive species) are unevenly distributed across lakes, across the seasonal cycle, and across space within lakes, potentially leading to highly variable water quality responses [...]

Centennial- and orbital-scale erosion beneath the Greenland Ice Sheet

Allie Balter-Kennedy, Nicolás E. Young, Jason P. Briner, et al.

Published: 2021-08-31
Subjects: Earth Sciences, Geochemistry, Geomorphology, Glaciology

Erosion beneath glaciers and ice sheets is a fundamental Earth-surface process dictating landscape development, which in turn influences ice-flow dynamics and the climate sensitivity of ice masses. The rate at which subglacial erosion takes place, however, is notoriously difficult to observe because it occurs beneath modern glaciers in a largely inaccessible environment. Here, we present 1) [...]

Oxidized Mantle Sources of HIMU and EM-type Ocean Island Basalts

Robert William Nicklas, Rachel K M Hahn, Lori N Willhite, et al.

Published: 2021-08-31
Subjects: Earth Sciences, Geochemistry, Geology

Oxygen fugacity (fO2) is a fundamental variable in igneous petrology with utility as a potential tracer of recycled surficial materials in the sources of mantle-derived lavas. It has been postulated that ocean island basalts (OIB) have elevated fO2 relative to mid-ocean ridge basalts (MORB) owing to more oxidized source regions. To clarify this issue, trace-element systematics of olivine grains [...]

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