Preprints
Filtering by Subject: Earth Sciences
The joint influence of break and noise variance on the break detection capability in time series homogenization
Published: 2017-12-15
Subjects: Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Instrumental climate records of the last centuries suffer from multiple breaks due to relocations and changes in measurement techniques. These breaks are detected by relative homogenization algorithms using the difference time series between a candidate and a reference. Modern multiple changepoint methods use a decomposition approach where the segmentation explaining most variance defines the [...]
Recycling of archaeal biomass as a new strategy for extreme life in Dead Sea deep sediments
Published: 2017-12-15
Subjects: Biogeochemistry, Chemistry, Earth Sciences, Organic Chemistry, Physical Sciences and Mathematics
Archaea and Bacteria that inhabit the deep subsurface (known as the deep biosphere) play a prevalent role in the recycling of sedimentary organic carbon. In such environments, this process can occur over millions of years and requires microbial communities to cope with extremely limited sources of energy. Because of this scarcity, metabolic processes come at a high energetic cost, but the ways [...]
The spectrum of slip behaviours of a granular fault gouge analogue governed by rate and state friction.
Published: 2017-12-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The exact principles of earthquake recurrence and magnitude are currently unknown which is why earthquake hazard assessment relies on statistical models combined with numerical simulations. A component of seismic and aseismic slip is the frictional character of a fault. We shear fused glass beads with a narrow particle size distribution of 300-400µm at stresses of 5-20kPa and with low shear rates [...]
The Apparent Stratification at the Top of Earths Liquid Core
Published: 2017-12-11
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earths magnetic field is generated by turbulent motion in its fluid outer core. Although the bulk of the outer core is vigorously convecting and well-mixed, some seismic, geomagnetic, and geodynamic evidence suggests that a global stably stratified layer exists at the top of Earths core. Such a layer would strongly influence thermal, chemical, and momentum exchange across the core-mantle boundary [...]
Stratigraphic modeling of the Western Taiwan foreland basin: sediment flux from a growing mountain range and tectonic implications
Published: 2017-12-11
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Sediment flux signals in foreland basins preserve a record of tectonics, sea level and climate through erosion and sedimentation. However, longitudinal sediment transport often occurs in foreland basin, thus removing part of the orogenic material flux from foreland basins. Here we use mass balance calculation and stratigraphic simulations of sediment fluxes for the Taiwan orogen to provide a [...]
Gender Representation of Speaking Opportunities at the American Geophysical Union Fall Meeting
Published: 2017-12-10
Subjects: Earth Sciences, Physical Sciences and Mathematics
Implicit and explicit biases impede the participation of women in geoscience. Documented biases include the quality of postdoctoral recommendation letters and opportunities to review research articles. Across career stages, attending conferences and presenting research are ways to spread scientific results, find job opportunities and funding, and gain awards and recognition. However, biases in [...]
Criteria and Tools for Determining Drainage Divide Stability
Published: 2017-12-09
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Watersheds are the fundamental organizing units in landscapes and thus the controls on drainage divide location and mobility are an essential facet of landscape evolution. Additionally, many common topographic analyses fundamentally assume that river network topology and divide locations are largely static, allowing channel profile form to be interpreted in terms of spatio-temporal patterns of [...]
Structural signatures of igneous sheet intrusion propagation
Published: 2017-12-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
The geometry and distribution of planar igneous bodies (i.e. sheet intrusions), such as dykes, sills, and inclined sheets, has long been used to determine emplacement mechanics, define melt source locations, and reconstruct palaeostress conditions to shed light on various tectonic and magmatic processes. Since the 1970’s we have recognised that sheet intrusions do not necessarily display a [...]
Multiphase flow characteristics of heterogeneous rocks from CO2 storage reservoirs in the United Kingdom
Published: 2017-12-08
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Oil, Gas, and Energy, Physical Sciences and Mathematics
We have studied the impact of heterogeneity on relative permeability and residual trapping for rock samples from the Bunter sandstone of the UK Southern North Sea, the Ormskirk Sandstone of the East Irish Sea, and the Captain Sandstone of the UK Northern North Sea. Reservoir condition CO2-brine relative permeability measurements were made while systematically varying the ratio of viscous to [...]
Tropical cyclones shift poleward more over Land than over Ocean
Published: 2017-12-07
Subjects: Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics
The latitudes of all Northern Hemisphere tropical cyclones (TCs) from the National Hurricane Center (NHC)/Joint Typhoon Warning Center (JTWC) best track data are used to investigate their poleward migration from 1970 to 2017. The annual means of the track latitudes are calculated for tropical storms, hurricanes/typhoons, and all storms over land and ocean, respectively. The analysis of the annual [...]
Characterising Drainage Multiphase Flow in Heterogeneous Sandstones
Published: 2017-12-07
Subjects: Earth Sciences, Engineering, Hydrology, Physical Sciences and Mathematics
In this work, we analyse the characterisation of drainage multiphase flow properties on heterogeneous rock cores using a rich experimental dataset and mm-m scale numerical simulations. Along with routine multiphase flow properties, 3D sub-metre scale capillary pressure heterogeneity is characterised by combining experimental observations and numerical calibration, resulting in a 3D numerical [...]
Inverse analysis to reconstruct hydraulic conditions of non-steady turbidity currents based on multiple grain-size classes
Published: 2017-12-06
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
This study proposes a new method of inverse analysis of ancient turbidites to represent non-steady turbidity currents and account for multiple grain-size classes. The forward model employed in this study is based on the shallow water equation, and the initial conditions of flows are assumed as a lock-exchange type. To obtain a solution to the inverse problem, a genetic algorithm is employed to [...]
Neogene - Quaternary slow coastal uplift of Western Europe through the perspective of sequences of strandlines from the Cotentin Peninsula (Normandy, France)
Published: 2017-12-06
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The Cotentin Peninsula (Normandy, France) displays sequences of marine terraces and rasas, the latter being wide Late Cenozoic coastal erosion surfaces, that are typical of Western European coasts in Portugal, Spain, France and southern England. Remote sensing imagery and field mapping enabled reappraisal of the Cotentin coastal sequences. From bottom to top, the N Cotentin sequence includes four [...]
Subsurface expression of a tertiary salt weld, Gulf of Mexico
Published: 2017-12-06
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Salt welds form due to salt expulsion and thinning by mechanical (e.g. salt flow) and/or chemical (e.g. salt dissolution) processes. Despite being ubiquitous in salt-bearing sedimentary basins, where they may trap large volumes of hydrocarbons, little is published on weld thickness and composition. We here use 3D seismic reflection, borehole, and biostratigraphic data from the Atwater Valley [...]
Types of mixing and heterogeneities in siliciclastic-carbonate sediments
Published: 2017-12-05
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Mixed siliciclastic-carbonate deposits consist of a suite of different types of mixing between the two components, from bed (core-plug) to stratigraphic (seismic) scales, producing a high vertical and lateral lithological variability. Mixed deposits result from the interaction of siliciclastic input and coeval carbonate production controlled by temporal and/or spatial factors. Although mixed [...]