Preprints
Filtering by Subject: Geology
Submarine channels "swept" downstream after bend cutoff in salt basins
Published: 2018-12-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Channel-bend expansion and downstream translation, as well as vertical movements by aggradation and incision, set the stratigraphic architecture of channelized depositional systems. Early work on submarine-channel evolution has suggested that downstream translation is rare. We propose that downstream translation of bends might be common in deep-water salt-tectonic provinces, where complex [...]
No evidence for sea level fall in the Cretaceous strata of the Book Cliffs of Eastern Utah
Published: 2018-12-08
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
A core component of the sequence stratigraphic model is the implicit assumption of a semi-sinusoidal relative sea-level curve, and the occurrence of “sequence boundaries” formed during intervals of sea-level fall, recognized primarily by the presence of incised valleys. Late Cretaceous paralic deposits in the Book Cliffs, Utah, have been one of the main testing and teaching grounds for [...]
Tectonic controls on deposition in the late Cambrian - Early Ordovician Central Andean Basin (Cordillera Oriental; northwest Argentina) – the first step towards an integrative reconstruction
Published: 2018-12-07
Subjects: Earth Sciences, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
This study focuses on upper Cambrian – Lower Ordovician strata containing the lowermost fossil-bearing levels of the basin (Santa Rosita Formation and Guayoc Chico Group). Bounded by two major regional unconformities, this stratigraphic interval was previously considered as a retro-arc foreland basin displaying evidence of westward progradation without tectonic activity during its deposition. [...]
Episodic fluid flow in an active fault
Published: 2018-11-30
Subjects: Earth Sciences, Geology, Hydrology, Physical Sciences and Mathematics, Tectonics and Structure
We present a 250 ka record of episodic fluid flow along the Malpais fault which hosts the Beowawe hydrothermal system, Nevada, USA. The history of fluid flow was quantified using a novel combination of the apatite (U-Th)/He (AHe) thermochronometer and a model of the thermal effects of fluid flow. Samples show partial resetting of the AHe thermochronometer in a 40 m wide zone around the normal [...]
Evolving marginal terranes during Neoproterozoic supercontinent reorganisation: constraints from the Bemarivo Domain in northern Madagascar
Published: 2018-11-30
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Madagascar is important for unravelling the geodynamic evolution of the transition between the Rodinia and Gondwana supercontinents as it contains several suites of c. 850–700 Ma magmatic rocks that have been postulated to correlate with other ex-Rodinia terranes. The Bemarivo Belt of northern Madagascar contains the youngest suite of these magmatic rocks that date to c. 750–700 Ma. We present [...]
A Small Scale Study of the Weathering Rates of Marble Gravestones Dated from 1958-1962
Published: 2018-11-12
Subjects: Earth Sciences, Environmental Sciences, Geology, Physical Sciences and Mathematics
Marble is known to weather quicker when exposed to air pollution. This has led to the suggestion that gravestones could be used to study the long term degradation of marble and be used as indicators of past pollution levels. This small scale study examined the weathering rates of a group of marble gravestones of similar age and location. The study found no evidence to suggest that these [...]
A PCA-based framework for determining remotely-sensed geological surface orientations and their statistical quality
Published: 2018-11-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Planetary Geology, Planetary Sciences, Planetary Sedimentology, Statistical Methodology, Statistics and Probability, Stratigraphy, Tectonics and Structure
The orientations of planar rock layers are fundamental to our understanding of structural geology and stratigraphy. Remote-sensing platforms including satellites, unmanned aerial vehicles (UAVs), and LIDAR scanners are increasingly used to build three-dimensional models of structural features on Earth and other planets. Remotely-gathered orientation measurements are straightforward to calculate [...]
Preservation of autogenic processes and allogenic forcings within set-scale aeolian architecture II: the scour-and-fill dominated Jurassic Page Sandstone, Arizona, USA
Published: 2018-11-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
The stratigraphic architecture of aeolian sandstones is thought to record signals originating from both autogenic dune behavior and allogenic environmental boundary conditions within which the dune field evolves. Mapping of outcrop-scale surfaces and sets of cross-strata between these surfaces for the Jurassic Page Sandstone near Page, Arizona, USA, demonstrates that the stratigraphic signature [...]
Growth folds above propagating normal faults
Published: 2018-11-07
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure
Growth folds above the upper tips of normal faults are ubiquitous in extensional settings, especially during the early phases of extension and in salt-rich basins. As slip accumulates on the underlying normal fault, the geometry and size of the fold changes. These changes reflect the dip, throw, displacement and propagation rate of the underlying normal fault, as well as the thickness and [...]
Spatial variability of late Holocene and 20th century sea-level rise along the Atlantic coast of the United States
Published: 2018-11-06
Subjects: Climate, Earth Sciences, Environmental Sciences, Geology, Geomorphology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Accurate estimates of global sea-level rise in the pre-satellite era provide a context for 21st century sea-level predictions, but the use of tide-gauge records is complicated by the contributions from changes in land level due to glacial isostatic adjustment (GIA). We have constructed a rigorous quality-controlled database of late Holocene sea-level indices from the U.S. Atlantic coast, [...]
Palaeoenvironmental and tectonic significance of Miocene lacustrine and palustrine carbonates (Ait Kandoula Formation) in the Ouarzazate Foreland Basin, Morocco.
Published: 2018-11-06
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Sedimentology
The Ouarzazate Basin is the southern foreland basin to the High Atlas Mountains in Morocco. The sedimentary fill records a sequence from the Eocene to Pleistocene that records the interplay between tectonics and climate. This study presents the first stable isotope and facies analyses of the Middle to Late Miocene Aït Ibrirn lacustrine Member (Aït Kandoula Formation). These data test whether [...]
Burial-related Compaction Modifies Intrusion-induced Forced Folds: Implications for Reconciling Roof Uplift Mechanisms using Seismic Reflection Data
Published: 2018-11-02
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Space for shallow-level sills and laccoliths is commonly generated by bending and uplift of overlying rock and sediment. This so-called ‘roof uplift’ produces forced folds, the shape and amplitude of which reflect the geometry of underlying intrusions. The surface expression of forced folds can therefore be inverted to constrain intruding magma body properties, whilst ancient forced folds provide [...]
Overpressure Transfer Through Interconnected Igneous Intrusions
Published: 2018-10-30
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Paper looking at the transference of overpressure through interconnected igneous intrusions within sedimentary basins. The manuscript highlights the current under-recognized hazard in both scientific and hydrocarbon drilling in vicinity of subsurface igneous complexes.
Flow-Substrate Interactions in Aggrading and Degrading Submarine Channels
Published: 2018-10-25
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geology, Geomorphology, Other Civil and Environmental Engineering, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Connecting real time measurements of current-bed interactions to the temporal evolution of submarine channels can be extremely challenging in natural settings. We present a suite of physical experiments that offer insight into the spectrum of interactions between turbidity currents and their channels, from (i) detachment-limited erosion to (ii) transport-limited erosion to (iii) pure deposition. [...]
The deposition and alteration history of the northeast Syrtis Major layered sulfates
Published: 2018-10-16
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
Ancient stratigraphy on Isidis Basins western margin records the history of water on early Mars. Noachian units are overlain by layered, basaltic-composition sedimentary rocks that are enriched in polyhydrated sulfates and capped by more resistant units. The layered sulfates – uniquely exposed at northeast Syrtis Major – comprise a sedimentary sequence up to 600-m thick that has undergone a [...]