Preprints
There are 5432 Preprints listed.
Evolution and architecture of an overbank in an ocean-facing canyon-fill.
Published: 2024-05-21
Subjects: Earth Sciences, Geology, Sedimentology
Submarine canyon-fills comprise substantial volumes of thin-bedded successions deposited by sediment gravity flows that are either stripped or overspill from adjacent channels into highly confined, topographically complex overbank settings. Here, we document the Punta Baja Formation, a rare example of an exhumed canyon-confined overbank succession with good 3D constraints from the Mesozoic [...]
At the Sharp End of Fractured Granites: A Critical Geology for Critical Times
Published: 2024-05-20
Subjects: Earth Sciences, Human Geography, Physical Sciences and Mathematics, Social and Behavioral Sciences
The geosciences have been positioned as integral to a ‘whole society’ transition that includes the decarbonisation of energy systems. Geothermal energy - which relies on a knowledge of the dynamism of rocks in the subsurface including the movement of fluids through fractures, physio-chemical interactions, and thermal gradients – has been offered as a potential route forward. Its realisation [...]
Remote Sensing of Environmental Impacts for IMACS
Published: 2024-05-20
Subjects: Physical Sciences and Mathematics
The Impact Measurement and Conservation System (IMACS) was developed to calculate environmental and human condition impacts and to apply conservation required to neutralize such impacts for products and services purchased by end-user consumers (1- 6). With its implementation, the IMACS system would allow the fastest return to the best approximation of pre-industrial sustainable conditions (Global [...]
A model of near-sea ice phytoplankton blooms
Published: 2024-05-20
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Arctic phytoplankton spring blooms have increased in magnitude and extent over the past two decades, particularly in waters near the sea ice edge. We develop an idealized model of phytoplankton dynamics that takes into account the role of sea ice meltwater flux and its impact on surface mixed layer depth. Satellite observations feature a characteristic peak in phytoplankton concentration at [...]
The Overlooked Sub-Grid Air-Sea Flux in Climate Models
Published: 2024-05-18
Subjects: Atmospheric Sciences, Climate, Numerical Analysis and Scientific Computing, Oceanography
Understanding air-sea interaction is crucial for our ability to predict future states of the climate system, and to inform economic and societal decision-making. However, the representation of air-sea interactions in climate models is limited by structural errors associated with model resolution. Coarse-resolution climate models do not resolve small-scale structures in the air-sea state, which, [...]
Unveiling the bioleaching versatility of Acidithiobacillus ferrooxidans
Published: 2024-05-17
Subjects: Life Sciences
Acidithiobacillus ferrooxidans, a Gram-negative bacterium thriving in extreme acidic conditions, has emerged as a key player in biomining and bioleaching technologies thanks to its unique ability to mobilize, directly or indirectly, a wide spectrum of elements, such as Li, P, V, Cr, Fe, Ni, Cu, Zn, Ga, As, Mo, W, Pb, U, and its role in ferrous iron oxidation, A. ferrooxidans catalyzes the [...]
Unconfined turbidity current interactions with oblique slopes: deflection, reflection and combined-flow behaviours
Published: 2024-05-17
Subjects: Geology
What is the nature of flow reflection, deflection and combined-flow behaviour when gravity flows interact with slopes? In turn, how do these flow dynamics control sedimentation on slopes? Here, these questions are addressed using physical experiments, with low-density unconfined gravity flows interacting with slopes of varying gradients, at a range of flow incidence angles. The present paradigm [...]
Land management controls on soil carbon fluxes in Asia’s largest tropical grassland
Published: 2024-05-17
Subjects: Environmental Monitoring, Natural Resources and Conservation, Other Life Sciences
Land management changes threaten the ecological functionality of grassland ecosystems worldwide, including the ability of these ecosystems to store carbon in their soils. The Banni grasslands, Asia’s largest tropical grassland, is no different in this regard. Despite being a highly biodiverse ecosystem with an extensive land use history, information on soil carbon fluxes in this ecosystem remains [...]
Bayesian Inversion with TimeOptMCMC
Published: 2024-05-16
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Statistical Methodology, Stratigraphy
TimeOptMCMC (Meyers and Malinverno, 2018) is a Bayesian approach for evaluating cyclostratigraphic records that quantitatively links geologic data with astronomical theory. This manuscript provides an introductory guide for conducting a TimeOptMCMC Bayesian inversion, following the approach of Meyers and Malinverno (2018). The purpose of this guide is to help users identify an appropriate data [...]
Mercury records from natural archives reveal ecosystem responses to changing atmospheric deposition
Published: 2024-05-15
Subjects: Atmospheric Sciences, Environmental Sciences, Geochemistry, Geography, Physical and Environmental Geography
Global ecosystems face mercury contamination, yet long-term data is scarce, hindering understanding of ecosystem responses to atmospheric Hg input changes. To bridge data gap and assess ecosystem responses, we compiled and compared a mercury accumulation database from peat, lake, ice, and marine deposits worldwide with atmospheric mercury deposition modeled by GEOS-Chem, focusing on trends, [...]
Projection of spatially explicit land use scenarios for the São Francisco River Basin, Brazil
Published: 2024-05-15
Subjects: Civil and Environmental Engineering
Future land use change in the São Francisco River Basin (SFRB) is critical to the future of regional climate and biodiversity, given the large heterogeneity among the four climate types within the basin. These changes in SFRB depend on the link between global and national factors due to its role as one of the world's major exporters of raw materials and national to local institutional, [...]
Global Warming is Industrially Suppressed Middle-School Science
Published: 2024-05-15
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The 15\% of the American public that denies global warming probably used middle-school science texts in which the topic was omitted at the behest of Big Oil. We attempt to remedy this with a simple explanation of the process, in which the 33°C difference between the Stefan-Bolzmann astrophysical -18°C temperature of the solar-heated planet and the Weather Bureau's comfortable 15°C sea-level [...]
Archetypal flow regime change classes as signatures of anthropogenic drivers of global streamflow alterations
Published: 2024-05-14
Subjects: Hydrology
Streamflow – a key component of the water cycle – is experiencing drastic alteration due to human actions. While existing studies have widely assessed the global extent and degree of this change, understanding of its drivers has been limited because previous global-scale approaches have largely relied on modelled hypothetical scenarios. Here, we overcome these limitations by providing a [...]
Synchrotron radiation reveals transient weakening during mineral phase transformations
Published: 2024-05-13
Subjects: Earth Sciences, Geology, Mineral Physics, Tectonics and Structure
Phase transformations are widely invoked as a source of rheological weakening during subduction, continental collision, mantle convection, and various other geodynamic phenomena. However, the likelihood and magnitude of such weakening in nature remains undetermined. Here, experiments performed on a synchrotron beamline reveal dramatic weakening across the polymorphic quartz↔coesite phase [...]
Ultramafic Melt Viscosity: A Model
Published: 2024-05-13
Subjects: Earth Sciences, Physical Sciences and Mathematics, Planetary Sciences
A non-Arrhenian model for the Newtonian viscosity (η) of ultramafic melts is presented. The model predicts the viscosity of ultramafic melts as a function of temperature (T), pressure (P), H2O content and for a range of melt compositions (70 < Mg# < 100). The calibration consists of 63 viscosity measurements at ambient pressure for 20 individual melt compositions and 5 high-P measurements [...]