Preprints
Filtering by Subject: Geology
PYRENAIC ROCK GLACIERS: AN AIRBORNE AND MULTITEMPORAL LiDAR MONITORING CASE STUDY IN THE BESIBERRI AREA
Published: 2019-10-24
Subjects: Earth Sciences, Environmental Sciences, Geology, Geomorphology, Glaciology, Physical Sciences and Mathematics
The monitoring of rock glaciers is a current subject of interest because of its application as permafrost indicator and its sensitivity to climatic changes (especially temperature and precipitation). Alpine rock glaciers in the Pyrenees have been described by various authors, but to study them regionally has been a challenge since most of these studies are based on ground-based techniques. Two [...]
Inheritance of penetrative basement anisotropies by extension-oblique faults: Insights from analogue experiments
Published: 2019-10-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
During rifting, pre-existing penetrative basement fabrics can affect new faults in cover rocks by a mechanism that does not appear to involve reactivation. This subtle form of inheritance can significantly impact fault network architecture in rift basins above laterally variable basement domains with geomechanical anisotropies. Here we use multi-layer, brittle-ductile, crustal-scale analogue [...]
Pre-breakup extension in the northern North Sea defined by complex strain partitioning and heterogeneous extension rates
Published: 2019-10-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The early stages of continental rifting are accommodated by the growth of upper-crustal normal fault systems that are distributed relatively evenly across the rift width. Numerous fault systems define fault arrays, the kinematics of which are poorly understood due to a lack of regional studies drawing on high-quality subsurface data. Here we investigate the long-term (~150 Myr) growth of a [...]
“Conjugate margins” – An oversimplification of the complex southern North Atlantic rift and spreading system?
Published: 2019-10-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The prevalence of conjugate margin terminology and studies in the scientific literature is testimony to the contribution that this concept and approach has made to the study of passive margins, and more broadly extensional tectonics. However, when applied to the complex rift, transform and spreading system of the southern North Atlantic (i.e. the passive margins of Newfoundland, Labrador, [...]
Four-dimensional Variability of Composite Halokinetic Sequences
Published: 2019-10-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The architecture of salt diapir-flank strata (i.e. halokinetic sequences) is controlled by the interplay between volumetric diapiric flux and sediment accumulation rate. Halokinetic sequences consist of unconformity-bounded packages of thinned and folded strata formed by drape-folding around passive diapirs. These sequences are described by two end-members: (i) hooks, which are characterized by [...]
Asperity failure control of stick-slip along brittle faults
Published: 2019-10-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Stick-slips are spontaneous, unstable slip events during which a natural or man-made system transitions from a strong, sticking stage to a weaker, slipping stage. Stick-slips were proposed by Brace and Byerlee (1966) as the experimental analogue of natural earthquakes. We analyze here the mechanics of stick-slips along brittle faults by conducting laboratory experiments and by modeling the [...]
An empirical approach to estimating hydrocarbon column heights for improved pre-drill volume prediction in hydrocarbon exploration
Published: 2019-10-03
Subjects: Analysis, Earth Sciences, Geology, Mathematics, Physical Sciences and Mathematics
Estimating pre-drill volumes in hydrocarbon exploration involves dealing with geological and technical uncertainties. The prediction of the hydrocarbon column height is widely recognized as the primary driver of uncertainty in volumetric estimates. The oil and gas industry continues to renew efforts to limit such uncertainties because of the potential economic costs of inaccurate estimation, yet [...]
Key controls on hydrocarbon retention and leakage from structural traps in the Hammerfest Basin, SW Barents Sea: implications for prospect analysis and risk assessment
Published: 2019-10-03
Subjects: Analysis, Earth Sciences, Geology, Geophysics and Seismology, Mathematics, Physical Sciences and Mathematics, Tectonics and Structure
Evidence of hydrocarbon leakage has been well documented across the SW Barents Sea and is commonly associated with exhumation in the Cenozoic. However, further study is required to understand what specific mechanism(s) facilitate such leakage, and why this occurs in some locations and not others. We use seismic and well data to quantify fault- and top-seal strength based on mechanical and [...]
Repeated degradation and progradation of a submarine slope over geological timescales
Published: 2019-09-30
Subjects: Earth Sciences, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
Submarine slopes prograde via accretion of sediment to clinoform foresets, and degrade in response to channel or canyon incision, or mass-wasting processes. The timescales over which progradation and degradation occur, and the large-scale stratigraphic record of these processes, remain unclear due poor age constraints in subsurface-based studies, and areally limited exposures of exhumed systems. [...]
The influence of local low-density basement anomalies on the distribution of fluvio-deltaic sediment in rift basins: the early Carboniferous Fell Sandstone Formation, northern England
Published: 2019-09-18
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Tectonics and Structure
Local low-density basement anomalies are an important part of a rift basin’s inherited structural framework that can influence basin stratigraphy. Large granitic intrusions can cause local alterations in the basement’s density and often spatially correlate with fault-bounded highs (blocks) or convex-shaped regional flexural highs due to their isostatic responses. We investigate the influence of [...]
Miniature paleo-speleothems from the earliest Ediacaran (635 Ma) Doushantuo cap dolostone in South China and their implications for terrestrial ecosystems
Published: 2019-09-15
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Speleology, Stratigraphy
Speleothems can offer insights into terrestrial life because their formation is critically dependent on soil-microbial ecosystems. Here we report the wide distribution of miniature paleo-speleothems from the ~635 Ma Doushantuo cap dolostone in South China in order to understand the recovery of terrestrial life after the terminal Cryogenian Marinoan snowball Earth glaciation. The cap dolostone was [...]
A report on gender diversity and equality at Tectonic Studies Group (TSG) meetings: 2007-2019.
Published: 2019-09-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The Tectonic Studies Group (TSG) is a specialist group of the Geological Society of London that was founded in 1970 as a forum for discussion of research in structural geology and tectonics. Here, we report on gender diversity and equality at the TSG annual conferences between 2007 and 2019. Gender diversity was analysed in the following categories: 1.) talks presented; 2.) posters presented; 3.) [...]
Methods and Test Cases for Linking Physics-Based Earthquake and Tsunami Models
Published: 2019-09-06
Subjects: Computer Sciences, Earth Sciences, Geology, Geophysics and Seismology, Other Computer Sciences, Physical Sciences and Mathematics
Despite the inter-dependence of long term deformation, earthquakes and tsunamis, few modelling approaches bridge these processes. To advance the understanding of tsunami generation and earthquake-tsunami interactions, we present new methods for linking physics-based models of subduction zone geodynamics and seismic cycling, three-dimensional dynamic earthquake rupture, and tsunami generation, [...]
The 1987 to 2019 Tennant Creek, Australia, earthquake sequence: a protracted intraplate multi-mainshock sequence
Published: 2019-09-06
Subjects: Earth Sciences, Geology, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The 1987 to 2019 Tennant Creek earthquake sequence comprises three 1988 surface-rupturing mainshocks (moment magnitude (Mw 6.2, 6.3, and 6.5) that occurred within a 12-hour period, a preceding foreshock sequence commencing in 1987, and a prolonged aftershock sequence including a Mw 5.0 earthquake on the 1st August 2019. Each surface rupturing event produced a distinct scarp; the south-dipping [...]
Grainstone cross-set geometry as a physical proxy for chemical and biological sediment cohesion
Published: 2019-09-06
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Preserved cross-set thicknesses are powerful tools for unravelling past environmental conditions. The relative rate of bedform aggradation to migration (climb angle) is encoded into the distribution of cross-set thicknesses. In siliciclastic settings, climb angles have been used to reconstruct properties of the depositional system, including ancient topography, which exerts a control on local [...]