Preprints
Filtering by Subject: Earth Sciences
DEM-based Geomorphological Mapping and Landforms Characterization of a Tropical Karst Environment in Southeastern Brazil
Published: 2018-08-23
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
This work presents a 1:10,000 geomorphological mapping of an area in southeastern Brazil, based on morphometric analysis of Digital Elevation Models (DEMs), while classical methods focus on photo interpretation. Data derived from the DEM include elevation, slope gradient, slope aspect, vertical and horizontal curvatures, amplitude, elongation and wavelength of landforms. These parameters were [...]
A calibration workflow for coastal dune models
Published: 2018-08-21
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Numerical models of coastal dune growth encode feedbacks and nonlinearities between sediment transport and plant growth. The range of processes and tunable parameters involved make model calibration an important step when using models for prediction. In this paper we outline a method to calibrate models of coastal dune formation and describe the process from end to end. The first step is [...]
Controls of basement fabric on rift coupling and development of normal fault geometries: Insights from the Rukwa – North Malawi Rift
Published: 2018-08-19
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The Rukwa Rift and North Malawi Rift Segments (RNMRS) both define a major rift-oblique segment of the East African Rift System (EARS), and although the two young rifts show colinear approaching geometries, they are often regarded as discrete rifts due to the presence of the intervening Mbozi Block uplift located in-between. This problem has been complicated by the dominance of the Rungwe volcanic [...]
Using polygonal layer-bound normal faults as tools to delimit clastic reservoirs in the Levant Basin offshore Lebanon
Published: 2018-08-19
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Tectonics and Structure
The Levant Basin offshore Lebanon contains an array of layer-bound normal faults in the Oligo-Miocene units. The faults are believed to have nucleated in soft-grained sediments similar to polygonal fault systems worldwide, and as a result are influenced by lithological heterogeneities in the host rock unit. We used 3D seismic data and amplitude extraction from offshore Lebanon to map deepwater [...]
Using bar preservation to constrain reworking in channel-dominated fluvial stratigraphy
Published: 2018-08-16
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Fluvial deposits comprising more than 80% channel facies are often thought to have accumulated during intervals of relatively slow subsidence in sedimentary basins. This interpretation stems from the conceptual model that migrating and avulsing rivers rework their own deposits during times of limited accommodation creation, preferentially removing and bypassing fine floodplain deposits. [...]
Zealandia 2008
Published: 2018-08-16
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Zealandia is a submerged continent in the southwest Pacific Ocean that can be regarded as a rifted part of eastern Australia and West Antarctica. Described simply, the pre-Gondwana-breakup Zealandia geological record is one of a Cambrian to Early Cretaceous Gondwana convergent margin, followed by Late Cretaceous continental rifting. Arizona Geological Society Digest 22, 227-233.
Landers 1992 "reloaded": Integrative dynamic earthquake rupture modeling
Published: 2018-08-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The 1992 $M_w$ 7.3 Landers earthquake is perhaps one of the best studied seismic events. However, many aspects of the dynamics of the rupture process are still puzzling, e.g. the rupture transfer between fault segments. We present 3D spontaneous dynamic rupture simulations, incorporating the interplay of fault geometry, topography, 3D rheology, off- fault plasticity and viscoelastic attenuation. [...]
Dalangtan Saline Playa in a Hyperarid Region of Tibet Plateua-III: Correlated Multiscale Surface Mineralogy and Geochemistry Survey
Published: 2018-08-15
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
We report the first multiscale, systematic field-based testing of correlations between orbital scale advanced spaceborne thermal emission and reflection radiometer visible near-infrared (VNIR)/shortwave infrared (SWIR) reflectance and thermal infrared relative emissivity and outcrop scale Raman spectroscopy, VNIR reflectance, X-ray diffraction (XRD), and laser-induced breakdown spectroscopy [...]
Weak and slow, strong and fast: How shear zones evolve in a dry continental crust (Musgrave Ranges, Central Australia)
Published: 2018-08-15
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The strike-slip Davenport Shear Zone in Central Australia developed during the Petermann Orogeny (~ 550 Ma) in an intracontinental lower crustal setting under dry sub-eclogite facies conditions (~ 650 °C, 1.2 GPa). This ca. 5 km wide mylonite zone encloses several large low-strain domains, allowing a detailed study of the initiation of shear zones and their progressive development. [...]
Intraplate seismic events off Sumatra: 3-D source evolution
Published: 2018-08-14
Subjects: Earth Sciences, Physical Sciences and Mathematics
Four large, dominantly strike-slip, earthquakes have occurred in recent years in the Wharton Basin off the coast of Sumatra. The southernmost was the Mw 7.9 event on 2000 June 18, followed by the largest known intraplate earthquake – the Mw 8.6 event on 2012 April 11, with an Mw 8.2 ‘aftershock’ within a few hours. The most recent Mw 7.8 event on 2016 March 2 happened in an area with no [...]
The different character of the recent eruptions of Galápagos shield volcanoes (Ecuador): La Cumbre vs. Sierra Negra
Published: 2018-08-14
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
In the last year, two Galápagos volcanoes had shown eruptive activity. The three observed eruptions produced multiple lava flows along eruptive fissures and vents covering several square kilometers. After eight years of quiescence, La Cumbre volcano, Fernandina Island experienced two short-lived eruptions, on 4 September 2017 and 16 June 2018. The eruptions were characterized by very short [...]
Quantification of the Bed-scale Architecture of Submarine Depositional Environments and Application to Lobe Deposits of the Point Loma Formation, California
Published: 2018-08-11
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
As of August 2018, this work is in review in "The Depositional Record", a journal from the IAS (International Association of Sedimentologists) Submarine-fan deposits form the largest sediment accumulations on Earth and host significant reservoirs for hydrocarbons. While many studies of ancient fan deposits qualitatively [...]
Characterisation of submarine depression trails driven by upslope migrating cyclic steps: Insights from the Ceará Basin (Brazil)
Published: 2018-08-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
Circular to elliptical topographic depressions, isolated or organized in trails, have been observed on the modern seabed in different contexts and water depths. Such features have been alternatively interpreted as pockmarks generated by fluid flow, as sediment waves generated by turbidity currents, or as a combination of both processes. In the latter case, the dip of the slope has been [...]
Ocean Drilling Perspectives on Meteorite Impacts
Published: 2018-08-08
Subjects: Earth Sciences, Geophysics and Seismology, Oceanography and Atmospheric Sciences and Meteorology, Paleobiology, Paleontology, Physical Sciences and Mathematics, Planetary Geomorphology, Planetary Geophysics and Seismology, Planetary Sciences, Stratigraphy
Extraterrestrial impacts are a ubiquitous process in the solar system, reshaping the surface of rocky bodies of all sizes. On early Earth, impact structures may have been a nursery for the evolution of life. More recently, a large meteorite impact caused the end-Cretaceous mass extinction, causing the extinction of 75% of species known from the fossil, including non-avian dinosaurs, and clearing [...]
New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan
Published: 2018-08-07
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
The Laurentian Fan is one of the largest submarine fans on the western margin of the North Atlantic. Recently acquired high-resolution multibeam bathymetric data (60 m horizontal resolution) reveal a major mass transport deposit (MTD) on the Western Levee of Western Valley (WLWV), covering >14 000 km2 in water depths from 3900 m to >5000 m. Typical submarine landslide features are observed [...]