Preprints
Filtering by Subject: Earth Sciences
Quantitative chemical mapping of plagioclase as a tool for the interpretation of volcanic stratigraphy: an example from Saint Kitts, Lesser Antilles
Published: 2021-02-01
Subjects: Earth Sciences, Geochemistry, Geology, Stratigraphy, Volcanology
Establishing a quantitative link between magmatic processes occurring at depth and volcanic eruption dynamics is essential to forecast the future behaviour of volcanoes, and to correctly interpret monitoring signals at active centres. Chemical zoning in minerals, which captures successive events or states within a magmatic system, can be exploited for such a purpose. However, to develop a [...]
Temperature and water depth effects on brGDGT distributions in sub-alpine lakes of mid-latitude North America
Published: 2021-02-01
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) in lake sediments are increasingly being used to reconstruct past temperatures. However, recent studies suggest that brGDGT distributions and concentrations vary with lake size and environmental conditions such as seasonality and its effects on water column temperature and chemistry. To test their use as a paleothermometer in high-altitude [...]
Shear wave velocity structure beneath North-Western Himalaya and adjoining areas
Published: 2021-01-30
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Shear wave velocity structure, together with Moho depths have been estimated in northwestern Himalaya, Hindu Kush and the Pamirs at a potential resolution of 0.5×0.5 degrees and at 1×1 degrees in the surrounding area, by inverting fundamental mode Rayleigh wave group velocities calculated from regional earthquake (Δ ≤ 2500 km) data, and also from their joint inversions with teleseismic receiver [...]
Upper Mississippi River Flow and Sediment Characteristics and Their Effect on a Harbor Siltation Case
Published: 2021-01-29
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geomorphology, Hydraulic Engineering, Physical Sciences and Mathematics, Sedimentology
Upper Mississippi River flow and sediment characteristics downstream of St. Louis are presented in this study. Available and measured data were used to assess a harbor siltation case and dredging needs. Such data are also useful to researchers and engineers conducting work in the Mississippi River and large rivers in general. Flows were characterized in terms of the mean annual hydrograph, flow [...]
Tectonic evolution of an Early Cryogenian late-magmatic basin in central Madagascar
Published: 2021-01-29
Subjects: Earth Sciences, Physical Sciences and Mathematics
Central and southern Madagascar comprise a number of distinctive Archaean crustal blocks (the Antongil-Masora and Antananarivo domains) overlain by Proterozoic supracrustal sequences, preserved in the East African Orogen. Here, we present U–Pb and Lu–Hf isotopic data for two supracrustal units from detrital and metamorphic zircon grains. The lower sequence is comprised of quartzite and [...]
COMMENT ON“RECENT GLOBAL DECLINE OF CO2 FERTILIZATION EFFECTS ON VEGETATION PHOTOSYNTHESIS”
Published: 2021-01-29
Subjects: Earth Sciences
Wang et al. (Science 370, 1295–1300, 2020) report a significant decline in CO$_2$ fertilization effects using photosynthesis proxies from long-term satellite records. We find that small systematic biases in AVHRR data impact their analysis to the degree that the key finding is not robust.
Back-propagating rupture evolution within a curved slab during the 2019 Mw 8.0 Peru intraslab earthquake
Published: 2021-01-29
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The 26 May 2019 Mw 8.0 Peru intraslab earthquake ruptured the subducting Nazca plate where the dip angle of the slab increases sharply and the strike angle rotates clockwise from the epicentre to north. To obtain a detailed seismic source model of the 2019 Peru earthquake, including not only the rupture evolution but also the spatiotemporal distribution of focal mechanisms, we performed [...]
Learning in a Crisis: Online Skill Building Workshop Addresses Immediate Pandemic Needs and Offers Possibilities for Future Trainings
Published: 2021-01-29
Subjects: Computer Sciences, Earth Sciences, Education, Geophysics and Seismology, Scholarship of Teaching and Learning
The COVID-19 pandemic led to the suspension of many summer research opportunities for STEM students. In response, the IRIS Education and Outreach program, in collaboration with Miami University, offered a free online Seismology Skill Building Workshop to increase undergraduates' knowledge, skills, self-efficacy, and interest in observational seismology and scientific computing. Registrations were [...]
Fault Throw and Regional Uplift Histories from Drainage Analysis: Evolution of Southern Italy
Published: 2021-01-26
Subjects: Earth Sciences, Geology, Geomorphology, Tectonics and Structure
Landscapes can record elevation changes caused by multiple tectonic processes. Here we show how coeval histories of spatially coincident normal faulting and regional uplift can be deconvolved from river networks. We focus on Calabria, a tectonically active region incised by rivers containing knickpoints and knickzones. Marine fauna indicate that Calabria has been uplifted by >1 km since [...]
Observational estimates of dynamic topography through space and time
Published: 2021-01-25
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure, Volcanology
Earth's mantle undergoes convection on million-year timescales as heat is transferred from depth to the surface. Whilst this flow has long been linked to the large-scale horizontal forces that drive plate tectonics and supercontinent cycles, geologists are increasingly recognising the signature of convection through transient vertical motions in the rock record, known as "dynamic topography". A [...]
Carbon dioxide removal through enhanced weathering of basalt on agricultural land –Assessing the potential in Austria
Published: 2021-01-23
Subjects: Earth Sciences, Environmental Sciences
Enhanced weathering through basalt application on agricultural land represents a proposed strategy for the removal of carbon dioxide from the atmosphere. It has been shown that enhanced weathering is principally feasible on a global scale, but it remains unclear whether it can be implemented on a local level. This information is however vital, to evaluate, if enhanced weathering should be further [...]
Evidence confirms an anthropic origin of Amazonian Dark Earths
Published: 2021-01-22
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geomorphology, Physical Sciences and Mathematics, Soil Science
First described over 120 years ago in Brazil, Amazonian Dark Earths (ADEs) are expanses of dark soil that are exceptionally fertile and contain large quantities of archaeological artefacts. The elevated fertility of the dark and often deep A horizon of ADEs is widely regarded as an outcome of pre-Columbian human influence. Controversially, in their recent paper Silva et al.2argue that the higher [...]
The building blocks of igneous sheet intrusions: insights from 3D seismic reflection data
Published: 2021-01-19
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
The propagating margins of igneous sills (and other sheet intrusions) may divide into laterally and/or vertically separated sections, which later inflate and coalesce. These components elongate parallel to and thus record the magma flow direction, and can form either due to fracture segmentation (i.e., ‘segments’) or brittle and/or non-brittle deformation of the host rock (i.e., ‘magma fingers’). [...]
Earthquake rupture on multiple splay faults and its effect on tsunamis
Published: 2021-01-17
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Detailed imaging of accretionary wedges reveals splay fault networks that could pose a significant tsunami hazard. However, the dynamics of multiple splay fault activation during megathrust earthquakes and the consequent effects on tsunami generation are not well understood. We use a 2-D dynamic rupture model with complex topo-bathymetry and six curved splay fault geometries constrained from [...]
Integrated magnetotelluric and petrological analysis of felsic magma reservoirs: Insights from Ethiopian rift volcanoes
Published: 2021-01-16
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Volcanology
Geophysical and petrological probes are key to understanding the structure and the thermochemical state of active magmatic systems. Recent advances in laboratory analyses, field investigations and numerical methods have allowed increasingly complex data-constraint models with new insights into magma plumbing systems and melt evolution. However, there is still a need for methods to quantitatively [...]