Preprints
Filtering by Subject: Earth Sciences
Stinging News: ‘Dickinsonia’ discovered in the Upper Vindhyan of India Not Worth the Buzz
Published: 2022-12-16
Subjects: Earth Sciences, Physical Sciences and Mathematics
A recent report of Dickinsonia tenuis ‘hiding in plain sight’ at the Bhimbetka rock shelters in rocks of the Maihar sandstone (Upper Vindhyan) has important implications for paleogeography and the age of the Upper Vindhyan. We visited the site in December 2022 and found the evidence for Dickisonia lacking. The ‘fossil’ resembles decayed parts of modern Apis dorsata (giant honeybees) hives. In [...]
Barometers behaving badly II: A critical evaluation of Cpx-only and Cpx-Liq thermobarometry in variably-hydrous arc magmas
Published: 2022-12-14
Subjects: Earth Sciences, Geochemistry, Geology, Volcanology
The chemistry of erupted clinopyroxene crystals (±equilibrium liquids) have been widely used to deduce the pressures and temperatures of magma storage in volcanic arcs. However, the large number of different equations parametrizing the relationship between mineral and melt compositions and intensive variables such as pressure and temperature yield vastly different results, with [...]
Transgressive rocky coasts in the geological record: Preserved or eroded? Insights from Miocene granitic rocky shorelines and modern examples.
Published: 2022-12-14
Subjects: Earth Sciences, Geology
Most of modern shorelines are in net erosion. Among these, rocky shorelines are commonly punctuated, with alternating high relief cliffs an incised embayments which host “pocket beaches”. While multiple cases of ancient rocky shorelines associated with low relief ravinement surfaces have been documented in the geological record, deposits formed in pocket beaches and joint-cut hollows are more [...]
Shortening ice seasons and changing phenology affect under-ice lake temperature dynamics
Published: 2022-12-13
Subjects: Earth Sciences, Environmental Sciences
Temperate lakes worldwide are losing ice cover but the implications for under-ice thermal dynamics are poorly constrained. Using a 92-year record of ice phenology from a temperate and historically dimictic lake, we examined trends, variability, and drivers of ice phenology and under-ice temperatures. The onset of ice formation decreased by 23 days century-1 which can be largely attributed to [...]
Citizen and Machine Learning-aided High-resolution mapping of urban heat exposure and stress
Published: 2022-12-13
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Through conversion of land cover to more built-up, impervious surfaces, cities are creating hotter environments for urban residents. Existing measurements of heat and heat stress, however, are often insufficient to capture intra-urban variability of exposure. This study provides a replicable method for modeling air temperature, humidity, and heat stress over an urban area, engaging citizens in [...]
Correlation of geological complexes of the Khan-Tengri Mountain massif
Published: 2022-12-09
Subjects: Earth Sciences, Geology, Stratigraphy, Tectonics and Structure
Researchers of the border regions of Xinjiang and the Central Asian countries are actively discussing two alternative models for the relationships between the main structural units of the Tianshan mountains. Most researchers believe that the Kyrgyz Middle Tianshan wedges out to the east along the Atbashi-Inylchek-Nalati marginal fault. According to the second hypothesis, the structures of the [...]
Basin-scale hydrodynamics and physical connectivity in a Great Patagonian Lake
Published: 2022-12-07
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Patagonian lakes are one of the most unexplored aquatic environments on Earth, and little is known about their thermo-hydrodynamics and current trophic state. Meanwhile, increasing urbanization and industrialization in their catchments compromise their health. Here, we investigate Lake Llanquihue, one of the Earth's great freshwater bodies in Northern Patagonia, Chile. Still considered a pristine [...]
Subsurface fracturing of sedimentary stones caused by bullet impacts
Published: 2022-12-04
Subjects: Earth Sciences
The immovable nature of built heritage means that it is particularly vulnerable during times of armed conflict. Although impacts from small arms and shrapnel leave relatively inconspicuous impact scars, they may elevate the risk of future stone deterioration. This study investigates the subsurface damage caused by bullet impacts, which is not apparent from surface inspection, in order to better [...]
An interconnected palaeo-subglacial lake system in the central Barents Sea
Published: 2022-12-03
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology, Sedimentology
Drainage of meltwater beneath an ice sheet influences ice-flow dynamics. To better predict ice sheet behaviour, it is crucial to understand subglacial hydrological processes. Subglacial lakes are important components of the subglacial hydrological system, with many observed and predicted at the beds of contemporary and palaeo-ice sheets. The technical and logistical challenges of studying [...]
Estimation and Uncertainty Quantification of Magma Interaction Times using Statistical Emulation
Published: 2022-12-02
Subjects: Applied Statistics, Earth Sciences, Physical Sciences and Mathematics, Volcanology
Evolution of volcanic plumbing systems towards eruptions of different styles and sizes largely depends on processes at crustal depths that are outside our observational capabilities. These processes can be modeled and the outputs of the simulations can be compared with the chemistry of the erupted products, geophysical and geodetic data to retrieve information on the architecture of the plumbing [...]
Laboratory validation of a new hydro-mechanical energy-based brittleness index model for hydraulic fracturing
Published: 2022-12-01
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Engineering Science and Materials, Mining Engineering, Oil, Gas, and Energy, Petroleum Engineering
Brittleness Index (BI) is a critical parameter characterising the deformation regime of geo-materials, covering the range from purely brittle (fractures) to ductile (plastic flow). A variety of BI models have been developed based on rock properties such as mineralogy, elastic parameters, or stress-strain data. However, very few of them are based on the deformation induced by hydro-mechanical [...]
Barometers behaving badly: Assessing the influence of analytical and experimental uncertainty on clinopyroxene thermobarometry calculations at crustal conditions
Published: 2022-12-01
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Volcanology
The composition of clinopyroxene and Clinopyroxene-Liquid (Cpx-Liq) pairs are frequently used to calculate crystallization/equilibration pressures in igneous systems. While canonical uncertainties are often assigned to calculated pressures based on fits to calibration or test datasets, the sources of these uncertainties (and thus ways to reduce them) have not been rigorously assessed. We show [...]
Additive Model Perturbations Scaled by Physical Tendencies for Use in Ensemble Prediction
Published: 2022-11-23
Subjects: Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics
Imperfections and uncertainties in forecast models are often represented in ensemble prediction systems by stochastic perturbations of model equations. In this article, we present a new technique to generate model perturbations. The technique is termed Additive Model-uncertainty perturbations scaled by Physical Tendencies (AMPT). The generated perturbations are independent between different model [...]
Geosphere and Biosphere coevolution: the role of trace metals availability in the evolution of biogeochemistry
Published: 2022-11-21
Subjects: Biochemistry, Biophysics, and Structural Biology, Biogeochemistry, Earth Sciences, Ecology and Evolutionary Biology, Microbiology, Planetary Sciences
Earth’s geosphere and biosphere have coevolved over time, influencing each other’s stability and keeping our planet habitable for most of its 4.543 billion years of history. Biogeochemical cycles play a key role in controlling this interaction, connecting long-term geological cycles and the much faster evolution of the Earth’s outer biologically dominated envelopes. A small set of [...]
The effect of uncertainties in creep activation energies on modeling ice flow and deformation
Published: 2022-11-21
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics
Ice deformation is commonly represented by a power-law constitutive relation, Glen's Flow Law, where deformation (strain) rate equals stress raised to the power n and multiplied by a flow-rate parameter A. Glen's Law represents bulk ice rheology as a single power-law even though multiple mechanisms, each with their own power-law relation and parametric values, act together during viscous [...]