Preprints
Filtering by Subject: Physical Sciences and Mathematics
What can radar-based measures of subglacial hydrology tell us about basal shear stress? A case study at Thwaites Glacier, West Antarctica
Published: 2023-08-29
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Ice sheet models use observations to infer basal shear stress, but the variety of methods and datasets available has resulted in a wide range of estimates. Radar-based metrics such as reflectivity and specularity content have been used to characterize subglacial hydrologic conditions that are linked to spatial variations in basal shear stress. We explore whether radar metrics can be used to [...]
Lithium isotope constraints on the plumeworld hypothesis for the Marinoan Snowball Earth
Published: 2023-08-27
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
The Snowball Earth hypothesis predicts that continental chemical weathering was curtailed substantially during but rebounded strongly after the Marinoan ice age some 635 million years ago. Defrosting the planet would result in a plume of fresh glacial meltwater with a different chemical composition than underlying hypersaline seawater, generating an onshore-offshore geochemical gradient. Here we [...]
Sea Ice Loss, Water Vapor Increases, and Their Interactions with Atmospheric Energy Transport in Driving Seasonal Polar Amplification
Published: 2023-08-25
Subjects: Physical Sciences and Mathematics
The ice-albedo feedback associated with sea ice loss contributes to polar amplification, while the water vapor feedback contributes to tropical amplification of surface warming. However, these feedbacks are not independent of atmospheric energy transport, raising the possibility of complex interactions that may obscure the drivers of polar amplification, in particular its manifestation across the [...]
Determining the Pressure – Temperature – Composition (P-T-X) conditions of magma storage
Published: 2023-08-24
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Determining the pressures and temperatures at which melts are stored in the crust and upper mantle, and the major element composition, redox state and volatile contents of these melts, is vital to constrain the structure and dynamics of magmatic plumbing systems. In turn, constraining these parameters helps understand the geochemical and structural evolution of the Earth’s lithosphere, and [...]
Biomarker Indicators of Past Climate
Published: 2023-08-24
Subjects: Physical Sciences and Mathematics
The molecular remainders of living organisms, found in sedimentary records, reflect past ecological, environmental and climatic conditions. Occurrence, abundance, relative distribution and even isotopic composition of these lipid biomarkers can be linked to climatic conditions. This chapter reviews organic proxies for past temperature, salinity, hydrology, sea ice conditions and biomass burning.
Earth's tectonic and plate boundary evolution over 1.8 billion years
Published: 2023-08-23
Subjects: Physical Sciences and Mathematics
Understanding the intricate relationships between the solid Earth and its surface systems in deep time necessitates comprehensive full-plate tectonic reconstructions that include evolving plate boundaries and oceanic plates. In particular, a tectonic reconstruction that spans multiple supercontinent cycles is important to understand the long-term evolution of Earth's interior, surface [...]
A proxy implementation of thermal pressurization for earthquake cycle modeling on rate-and-state faults
Published: 2023-08-22
Subjects: Physical Sciences and Mathematics
The reduction of effective normal stress during earthquake slip due to thermal pressurization of fault pore fluids is a significant fault weakening mechanism. Explicit incorporation of this process into frictional fault models involves solving the diffusion equations for fluid pressure and temperature outside the fault at each time step, which significantly increases the computational complexity. [...]
GossenAIA2015-RapaNuislides
Published: 2023-08-21
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
A slide presentation from AIA 116th Annual Conference, New Orleans, Jan 8-11 2015. The 149 slides in pdf format are from the original Keynote presentation: Deforestation, Drought and Humans: The Collapse Theory is Dead-New Evidence of Sustainability and Survival.
Temperature and hydrological variations during the Late-Glacial in the central Mediterranean: application of the novel ostracod-clumped isotope thermometer
Published: 2023-08-19
Subjects: Physical Sciences and Mathematics
This study shows, for the first time, the absence of a vital effect in the clumped isotope carbonate (Δ47) fossil ostracod signal and confirms the ability of the novel ostracod-Δ47 thermometer to reconstruct past temperatures and hydrological conditions in complex lacustrine systems. Furthermore, the application of Δ47 analyses on the ostracod species Candona angulata and Cyprideis torosa from [...]
Beyond microbial carbon use efficiency
Published: 2023-08-17
Subjects: Biogeochemistry, Earth Sciences, Environmental Microbiology and Microbial Ecology Life Sciences, Life Sciences, Physical Sciences and Mathematics, Soil Science
Microbial carbon use efficiency (CUE) is defined as the proportion of microbial biomass growth C versus substrate C uptake, and thus provides a useful measure of microbially driven accumulation and loss of soil organic carbon (SOC) 1. In a recent study published in Nature 2, the authors use a data-driven machine learning approach to conclude that CUE promotes global SOC storage based on a [...]
imc-precip-iso: Open monthly stable isotope data of precipitation over the Indonesian Maritime Continent
Published: 2023-08-12
Subjects: Climate, Earth Sciences, Environmental Sciences, Fresh Water Studies, Hydrology, Physical Sciences and Mathematics, Water Resource Management
Stable isotopes, $\delta^2$H, $\delta^{18}$O, and d-excess, are valuable tools as natural tracers of diffusion processes and phase changes in the global hydroclimatological cycle. The Indonesian Maritime Continent (IMC) is an archipelago area surrounded by very warm waters which induce convective activities as the primary heat source driving global atmospheric circulation. Given the central role [...]
CEDAR-GPP: spatiotemporally upscaled estimates of gross primary productivity incorporating CO2 fertilization
Published: 2023-08-10
Subjects: Earth Sciences, Physical Sciences and Mathematics
Gross primary productivity (GPP) is the largest carbon flux in the Earth system, playing a crucial role in removing atmospheric carbon dioxide and providing the sugars and starches needed for ecosystem metabolism. Despite the importance of GPP, however, existing estimates present significant uncertainties and discrepancies. A key issue is the underrepresentation of the CO2 fertilization effect, a [...]
Eocene (50-55 Ma) greenhouse climate recorded in nonmarine rocks of San Diego, CA, USA
Published: 2023-08-08
Subjects: Chemistry, Climate, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Soil Science, Stratigraphy
Nonmarine rocks in sea cliffs of southern California store a detailed record of weathering under tropical conditions millions of years ago, where today the climate is much drier and cooler. This work examines early Eocene (~50-55 million-year-old) deeply weathered paleosols (ancient, buried soils) exposed in marine terraces of northern San Diego County, California, and uses their geochemistry and [...]
Exclusive Seismoacoustic Detection and Characterization of an Unseen and Unheard Fireball Over the North Atlantic
Published: 2023-08-08
Subjects: Astrophysics and Astronomy, Earth Sciences, Physical Sciences and Mathematics
Small meteoroids that enter Earth's atmosphere often go unnoticed because their detection and characterization rely on human observations, introducing observational biases in space and time. Acoustic shockwaves from meteoroid ablation convert to infrasound and seismic energy, enabling fireball detection using seismoacoustic methods. We analyzed an unreported fireball in 2022 near the Azores, [...]
Seismic Activities in Ghana: A Systematic Review
Published: 2023-08-08
Subjects: Education, Physical Sciences and Mathematics
Seismic activities pose significant challenges to societies globally. Therefore, it is crucial to understand their occurrence, patterns, and impacts. By studying seismic activities, including earthquakes, researchers can investigate their occurrence, distribution, and characteristics which can provide effective management and risk reduction strategies. The southern part of Ghana is prone to [...]