Preprints
Filtering by Subject: Physical Sciences and Mathematics
Three Billion Year Secular Evolution of the Triple Oxygen Isotope Composition of Marine Chert
Published: 2019-05-08
Subjects: Earth Sciences, Geochemistry, Other Earth Sciences, Physical Sciences and Mathematics
The 18O/16O ratios of ancient marine minerals show a puzzling increase over geologic time. Long-term changes in temperature, seawater 18O/16O ratios, and post-depositional overprinting can all explain this trend, but few tracers can distinguish between these scenarios. Here, we report high-precision 18O/16O and 17O/16O ratios of cherts through 3.4 Ga of Earth′s history. We find that Phanerozoic [...]
Causation of Late Quaternary Rapid-increase Radiocarbon Anomalies
Published: 2019-05-08
Subjects: Astrophysics and Astronomy, Cosmochemistry, Earth Sciences, Physical Sciences and Mathematics
Brief (<100 y) rapid-increase anomalies in the Earth’s atmospheric 14C production have previously been attributed to either gamma photon radiation from supernovae or to cosmic ray particle radiation from exceptionally large solar flares. Analysis of distances and ages of nearby supernovae (SNe) remnant surveys, the probable gamma emissions, the predicted Earth-incident radiation, and the [...]
Identification and Characterization of a Buried Volcanic Field Using Seismic Reflection and Borehole Data
Published: 2019-05-06
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Buried volcanoes occur in great numbers within sedimentary basins globally. Knowledge of ancient buried volcanic systems has improved significantly over the past two decades. The in-depth understanding of these buried systems was mainly possible due to increasing availability of high-quality seismic reflection and sub-surface borehole data. This paper examines a cluster of Miocene volcanoes now [...]
Paleogeographic and Morphologic Reconstroction of a Buried Monogenetic Volcanic Field
Published: 2019-05-06
Subjects: Earth Sciences, Geology, Life Sciences, Physical Sciences and Mathematics
Technological advances of our modern society motivated an unprecedented necessity to find natural resources in the subsurface of our planet. The search for these valuable resources has revealed an unexpected number of ancient volcanoes buried and preserved within sedimentary basins globally. Continuous improvements in remote sensing techniques such as seismic reflection can provide a valid [...]
Pre-existing intra-basement shear zones influence growth and geometry of non-colinear normal faults, western Utsira High–Heimdal Terrace, North Sea
Published: 2019-05-06
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Pre-existing intra-basement shear zones can induce mechanical and rheological heterogeneities that may influence rifting and the overall geometry of rift-related normal faults. However, the extent to which physical and kinematic interaction between pre-existing shear zones and younger rift faults control the growth of normal faults is less-well understood. Using 3D reflection seismic data from [...]
Microstructural Constraints on Magmatic Mushes under Kīlauea Volcano, Hawaiʻi
Published: 2019-05-06
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics, Physical Sciences and Mathematics, Volcanology
Distorted olivines of enigmatic origin are ubiquitous in erupted products from a wide range of volcanic systems (e.g., Hawaiʻi, Iceland, Andes). Investigation of these features at Kīlauea Volcano, Hawai’i, using an integrative crystallographic and chemical approach places quantitative constraints on mush pile thicknesses. Electron back-scatter diffraction (EBSD) reveals that the microstructural [...]
Dating and morpho-stratigraphy of uplifted marine terraces in the Makran subduction zone (Iran)
Published: 2019-05-03
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
The western part of the Makran subduction zone (Iran) is currently experiencing active surface uplift, as attested by the presence of emerged marine terraces along the coast. To better understand the uplift recorded by these terraces, we investigated seven localities along the Iranian Makran and we performed radiocarbon, 230Th/U and optically stimulated luminescence (OSL) dating of the layers of [...]
A first look at dissolved Ge isotopes in marine sediments
Published: 2019-04-28
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
The removal of chemical species from seawater during the precipitation of authigenic minerals is difficult to constrain but may play a major role in the global biogeochemical cycles of some elements, including silicon (Si) and germanium (Ge). Here, we present Ge/Si, δ74Ge, and supporting chemical data of pore waters and core incubations at three continental margin sites in California and the Gulf [...]
Probabilistic space- and time-interaction modeling of main-shock earthquake rupture occurrence
Published: 2019-04-28
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics, Statistical Models, Statistics and Probability, Structural Engineering
This paper presents a probabilistic formulation for modeling earthquake rupture processes of mainshocks. A correlated multivariate Bernoulli distribution is used to model rupture occurrence. The model captures time interaction through the use of Brownian passage-time (BPT) distributions to assess rupture interarrival in multiple sections of the fault, and it also considers spatial interaction [...]
Terrestrial environmental change across the onset of the PETM and the associated impact on biomarker proxies: a cautionary tale
Published: 2019-04-28
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
The Paleocene-Eocene Thermal Maximum (PETM; ~ 56 million years ago (Ma) is the most severe carbon cycle perturbation event of the Cenozoic. Although the PETM is associated with warming in both the surface (~up to 8°C) and deep ocean (~up to 5°C), there are relatively few terrestrial temperature estimates from the onset of this interval. The associated response of the hydrological cycle during the [...]
A long-term, high-latitude record of Eocene hydrological change in the Greenland region
Published: 2019-04-26
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
A range of proxy approaches have been used to reconstruct short-term changes to Earth’s hydrological cycle during the early Eocene hyperthermals. However, little is known about the response of Earth’s hydrological and biogeochemical systems to long-term Cenozoic cooling, which began following the Early Eocene Climatic Optimum (53.3 – 49.4 million years ago; Ma). Here, we use the molecular [...]
Stratigraphy of Architectural Elements of a Buried Monogenetic Volcanic System and Implications for Geoenergy Exploration
Published: 2019-04-26
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Large volumes of magma emplaced and deposited within sedimentary basins can have an impact on their architectural style and geological evolution. Over the last decade, continuous improvement in techniques such as seismic volcano-stratigraphy and 3D seismic visualization of igneous rocks buried in sedimentary basins has helped increase knowledge about these “volcanic basins”. Here, we unravel the [...]
Application of multivariate statistical methods to hydrogeological property parameterisation from geotechnical and geophysical data
Published: 2019-04-26
Subjects: Earth Sciences, Environmental Sciences, Geology, Hydrology, Other Earth Sciences, Physical Sciences and Mathematics, Water Resource Management
Hydrogeological data sets are often relatively sparse compared to the scale of investigation, resulting in degrees of uncertainty which, although constrained, may be considered as not acceptable for achieving the desired precision in numerical modelling. The potential use of multivariate statistical methods in identifying correlations between geotechnical properties of the rock mass and hydraulic [...]
Bayesian parameter estimation for space and time interacting earthquake rupture model using historical and physics-based simulated earthquake catalogs
Published: 2019-04-25
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics, Risk Analysis
This paper presents a robust parameter estimation technique for a probabilistic earthquake hazard model that captures time and space interactions between earthquake mainshocks. The approach addresses the existing limitations of parameter estimation techniques by developing a Bayesian formulation and leveraging physics-based simulated synthetic catalogs to expand the limited datasets of historical [...]
Influence of dissolution on frictional properties of carbonate faults
Published: 2019-04-25
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics
Velocity stepping experiments have been performed on a simulated calcite gouge using an annular shear apparatus to investigate the effect of dissolution on the frictional properties of a carbonate fault. The tested material was put in contact with hydrochloric acid at different concentration in order to dissolve the grains. Particle size analysis shows that the small grains tend to disappear due [...]