Preprints
Filtering by Subject: Physical Sciences and Mathematics
Melting conditions and mantle source composition from probabilistic joint inversion of major and rare earth element concentrations
Published: 2021-08-12
Subjects: Physical Sciences and Mathematics
The chemical composition of erupted basalts provides a record of the thermo-chemical state of their source region and the melting conditions that lead to their formation. Here we present the first probabilistic inversion framework capable of inverting both trace and major element data of mafic volcanic rocks to constrain mantle potential temperature, depth of melting, and major and trace element [...]
Systematic calculation of finite-time mixed singular vectors and characterization of error growth for persistent coherent atmospheric disturbances over Eurasia
Published: 2021-08-12
Subjects: Physical Sciences and Mathematics
Singular vectors (SVs) have long been employed in the initialization of ensemble numerical weather prediction (NWP) in order to capture the structural organization and growth rates of those perturbations or “errors” associated with initial condition errors and instability processes of the large scale flow. Due to their (super) exponential growth rates and spatial scales, initial SVs are typically [...]
Storage, evolution, and mixing in basaltic eruptions from around the Okataina Volcanic Centre, Taupō Volcanic Zone, Aotearoa New Zealand
Published: 2021-08-07
Subjects: Physical Sciences and Mathematics
Volcanic Zone, Aotearoa New Zealand. Although best known for its high rates of explosive rhyolitic volcanism, there are several examples of basaltic to basaltic-andesite contributions to OVC eruptions. These range from minor involvement of basalt in rhyolitic eruptions to the exclusively basaltic 1886 C.E. plinian eruption of Tarawera. To explore the basaltic component supplying this dominantly [...]
Geochemical constraints on the structure of the Earth’s deep mantle and the origin of the LLSVPs
Published: 2021-08-03
Subjects: Physical Sciences and Mathematics
Geophysical analysis of the Earth’s lower mantle has revealed the presence of two superstructures characterized by low shear wave velocities on the core-mantle boundary. These Large Low Shear Velocity Provinces (LLSVPs) play a crucial role in the dynamics of the lower mantle and act as the source region for deep-seated mantle plumes. However, their origin, and the characteristics of the [...]
Cryoturbation leads to iron-organic carbon associations along a permafrost soil chronosequence in northern Alaska
Published: 2021-08-02
Subjects: Physical Sciences and Mathematics
In permafrost soils, substantial amounts of organic carbon (OC) are potentially protected from microbial degradation and transformation into greenhouse gases by association with reactive iron (Fe) minerals. As permafrost environments respond to climate change, increased drainage of thaw lakes in permafrost regions is predicted. Soils will subsequently develop on these drained thaw lakes, but the [...]
Competition between 3D structural inheritance and kinematics during rifting: insights from analogue models
Published: 2021-08-01
Subjects: Physical Sciences and Mathematics
The competition between the impact of inherited weaknesses and plate kinematics determines the location and style of deformation during rifting, yet the relative impacts of these “internal” and “external” factors remain poorly understood, especially in 3D. In this study we used brittle-viscous analogue models to assess how multiphase rifting, i.e., changes in plate divergence rate or direction, [...]
Microbial iron(III) reduction during palsa collapse promotes greenhouse gas emissions before complete permafrost thaw
Published: 2021-07-30
Subjects: Physical Sciences and Mathematics
Reactive iron (Fe) minerals can preserve organic carbon (OC) in soils overlying intact permafrost. With permafrost thaw, reductive dissolution of iron minerals releases Fe and OC into the porewater, potentially increasing the bioavailability of OC for microbial decomposition. However, the stability of this so-called rusty carbon sink, the microbial community driving mineral dissolution, the [...]
A theory of spontaneous tropical cyclogenesis from quasi-random convection
Published: 2021-07-30
Subjects: Physical Sciences and Mathematics
How the cumulus clouds organize into a tropical cyclone remains poorly understood. The difficulty lies in that the deep convection is noisy at the kilometer scale, but follows the physical feedbacks at the mesoscale. We build a barotropic numerical model to understand the interaction of the stochastic and deterministic processes in the genesis of a tropical depression. Deep convection is [...]
Imprint of the Pacific Walker Circulation in global precipitation δ18O
Published: 2021-07-30
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
*This article is now published, and freely available from Journal of Climate at https://doi.org/10.1175/JCLI-D-21-0190.1* Characterising variability in the global water cycle is fundamental to predicting impacts of future climate change; understanding the role of the Pacific Walker circulation (PWC) in the regional expression of global water cycle changes is critical to understanding this [...]
Strengths and limitations of in situ U-Pb titanite petrochronology in polymetamorphic rocks: An example from western Maine, USA.
Published: 2021-07-29
Subjects: Earth Sciences, Geochemistry, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Titanite is a potentially powerful U-Pb petrochronometer that may record metamorphism, metasomatism, and deformation. Titanite may also incorporate significant inherited Pb, the correction for which may introduce inaccuracies and result in geologically ambiguous U-Pb dates. Here we present laser ablation inductively coupled mass spectrometry (LA-ICP-MS)-derived titanite U-Pb dates and trace [...]
Kinking facilitates grain nucleation and modifies crystallographic preferred orientations during high-stress ice deformation
Published: 2021-07-28
Subjects: Earth Sciences, Physical Sciences and Mathematics, Planetary Sciences
Kinking can accommodate significant amounts of strain during crystal plastic deformation under relatively large stresses and may influence the mechanical properties of cold planetary cryosphere. To better understand the origins, mechanisms, and microstructural effects of kinking, we present detailed microstructural analyses of coarse-grained ice (~1300 µm) deformed under uniaxial compression at [...]
The impact of spatially varying ice sheet basal conditions on sliding at glacial time scales
Published: 2021-07-28
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Spatially variable basal conditions are thought to govern how ice sheets behave at glacial time scales (>1000 years) and responsible for changes in dynamics between the core and peripheral regions of the Laurentide and Fennoscandian ice sheets. Basal motion is accomplished via the deformation of unconsolidated sediments, or via sliding of the ice over an undeformable bed. We present an ice sheet [...]
Rapid prediction of alongshore run-up distribution from near-field tsunamis
Published: 2021-07-27
Subjects: Engineering, Physical Sciences and Mathematics
Rapid prediction of the spatial distribution of the run-up from near- field tsunamis is critically important for tsunami hazard characterization. Even though significant advances have been made over the last decade, physics- based numerical models are still computationally intensive. Here, we present a response surface methodology (RSM)-based model called the tsunami run-up response function [...]
The Mechanics of Initiation and Development of Thrust Ramps
Published: 2021-07-27
Subjects: Physical Sciences and Mathematics
We examine the mechanics of thrust fault initiation and development in sedimentary rocks which accounts for vertical variation in mechanical strength of the rocks. We use numerical mechanical models of mechanically layered rocks to examine thrust ramp nucleation in competent units, and fault propagation upward and downward into weaker units forming folds at both fault tips. We investigate the [...]
Contrasting geomorphic and stratigraphic responses to normal fault development during single and multi-phase rifting
Published: 2021-07-27
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
Understanding the impact of tectonics on surface processes and the resultant stratigraphic evolution in multi-phase rifts is challenging, as patterns of erosion and deposition related to older phases of extension are overprinted by the subsequent extensional phases. In this study, we use a one-way coupled numerical modelling approach between a tectonic and a surface processes model to investigate [...]