Preprints
Filtering by Subject: Geology
Rivers, reefs, and deltas; Geomorphological evolution of the Jurassic of the Farsund Basin, offshore southern Norway
Published: 2018-04-27
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
In many petroleum-bearing, data-poor ‘frontier’ basins, source, reservoir, and seal distribution is poorly constrained, making it difficult to identify petroleum systems and play models. However, 3D seismic reflection data provide an opportunity to directly map the three-dimensional distribution of key petroleum system elements, thereby supplementing typically sparse, one-dimensional sedimentary [...]
Tracking CO2 plumes in clay-rich rock by distributed fiber optic strain sensing (DFOSS): a laboratory demonstration
Published: 2018-04-26
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Fluid Dynamics, Geology, Geophysics and Seismology, Hydrology, Mineral Physics, Oil, Gas, and Energy, Optics, Physical Sciences and Mathematics, Physics
Monitoring the migration of pore pressure, deformation, and saturation plumes with effective tools is important for the storage and utilization of fluids in underground reservoirs, such as geological stores of carbon dioxide (CO2) and natural gas. Such tools would also verify the security of the fluid contained reservoir–caprock system. Utilizing the swelling strain attributed to pressure [...]
Controls on early‐rift geometry: new perspectives from the Bilila‐Mtakataka fault, Malawi
Published: 2018-04-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
This study investigates the controls to fault and rift geometry for a young rift system. Our case study is a large fault in southern Malawi. The geometry of the fault at the surface, the scarp, and structures within the rocks the fault cuts through, are measured. We also calculate the scarp height. The orientation and height of the fault scarp implies that local stresses influence its geometry, [...]
Bimodal or quadrimodal? Statistical tests for the shape of fault patterns
Published: 2018-04-23
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Natural fault patterns, formed in response to a single tectonic event, often display significant variation in their orientation distribution. The cause of this variation is the subject of some debate: it could be ‘noise’ on underlying conjugate (or bimodal) fault patterns or it could be intrinsic ‘signal’ from an underlying polymodal (e.g. quadrimodal) pattern. In this contribution, we present [...]
Strain analysis of a seismically-imaged mass-transport complex, offshore Uruguay
Published: 2018-04-23
Subjects: Earth Sciences, Engineering, Geology, Life Sciences, Physical Sciences and Mathematics
Strain style, magnitude, and distribution within mass-transport complexes (MTCs) is important for understanding the process evolution of submarine mass flows and for estimating their runout distances. Structural restoration and quantification of strain in gravitationally-driven passive margins have been shown to approximately balance between updip extensional and downdip compressional domains; [...]
Sedimentary Architecture of an Ancient Linear Megadune (Barremian, Neuquén Basin): Insights into the Long-Term Development and Evolution of Aeolian Linear Bedforms
Published: 2018-04-21
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
Linear aeolian bedforms are the most abundant bedform type in modern Earth sand seas and are very common in our Solar System. Despite their abundance, the long-term development of these bedforms and its impact upon the resulting sedimentary architecture in the geological record is still poorly understood. The aims of this paper are to study the exposed record of an ancient linear megadune in [...]
Present-day stress orientations in the Great Sumatran Fault in North Sumatra
Published: 2018-04-21
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Trench-parallel strike slip faults develop at lithospheric scale during oblique high-angle subduction. A “sliver” plate forms due to slip partitioning between the subduction plane (margin-normal slip) and the strike slip fault (margin-parallel slip). This process ultimately controls the location of volcanoes and earthquakes. The Great Sumatran Fault (GSF) is a showcase of this tectonic [...]
The relationships between regional Quaternary uplift, deformation across active normal faults and historical seismicity in the upper plate of subduction zones: The Capo D’Orlando Fault, NE Sicily.
Published: 2018-04-20
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics
In order to investigate deformation within the upper plate of the Calabrian subduction zone we have mapped and modelled a sequence of Late Quaternary palaeoshorelines tectonically‐deformed by the Capo D’Orlando normal fault, NE Sicily, which forms part of the actively deforming Calabrian Arc. In addition to the 1908 Messina Strait earthquake (Mw 7.1), this region has experienced damaging [...]
Pre-Alpine contrasting tectono-metamorphic evolutions within the Southern Steep Belt, Central Alps
Published: 2018-04-17
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
In the Southern Steep Belt, Italian Central Alps, relicts of the pre-Alpine continental crust are preserved. Between Valtellina and Val Camonica, a poly-metamorphic rock association occurs, which belongs to the Austroalpine units and includes two classically subdivided units: the Languard-Campo nappe (LCN) and the Tonale Series (TS). The outcropping rocks are low to medium grade muscovite, [...]
Crustal strain in the Marmara pull-apart region associated with the propagation process of the North Anatolian Fault
Published: 2018-04-11
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure
Propagation processes of plate-scale faults through continental lithosphere are poorly documented. The North Anatolian fault (NAF) is a continental right-lateral transform with striking evidence for propagation processes in the Marmara Sea pull-apart region. Earlier work [Armijo et al., 1999] suggests that in the Dardanelles, where the principal, northern branch of that fault (NNAF) enters into [...]
Rheological transitions facilitate fault-spanning ruptures on seismically active and creeping faults
Published: 2018-03-27
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
The apparent stochastic nature of earthquakes poses major challenges for earthquake forecasting attempts. Physical constraints on the seismogenic potential of major fault zones may aid in improving seismic hazard assessments, but the mechanics of earthquake nucleation and rupture are obscured by the complexity that faults display. In this work, we investigate the mechanisms behind giant [...]
Investigation of variable aeration of monodisperse mixtures: implications for Pyroclastic Density Currents
Published: 2018-03-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
The high mobility of dense pyroclastic density currents (PDCs) is commonly attributed to high gas pore pressures. However, the influence of spatial and temporal variations in pore pressure within PDCs has yet to be investigated. Theory suggests that variability in the fluidisation and aeration of a current will have a significant control on PDC flow and deposition. In this study, the effect of [...]
Monoclinal flexure of an orogenic plateau margin during subduction, south Turkey
Published: 2018-03-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Geologic evidence across orogenic plateau margins enables the discrimination of the relative contributions of orogenic, epeirogenic and/or climatic processes that lead to growth and maintenance of those plateaus and their margins. Here, we discuss the mode of formation of the southern margin of the Central Anatolian Plateau (SCAP) and evaluate its time of formation using fieldwork in the onshore [...]
Resolving the era of river-forming climates on Mars using stratigraphic logs of river-deposit dimensions
Published: 2018-03-11
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
River deposits are one of the main lines of evidence that tell us that Mars once had a climate different from today, and so changes in river deposits with time tell us something about how Mars climate changed with time. In this study, we focus in on one sedimentary basin – Aeolis Dorsa – which contains an exceptionally high number of exceptionally well-preserved river deposits that appear to have [...]
Mechanical models to estimate the paleostress state from igneous intrusions
Published: 2018-03-09
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Dikes and sills represent an important component of the deformation history in volcanic systems, but unlike dikes, sills are typically omitted from traditional paleostress analyses in tectonic studies. The emplacement of sheet intrusions is commonly associated with mode I fracturing in a low deviatoric stress state, where dilation is perpendicular to the fracture plane. Many natural examples of [...]