Preprints
Filtering by Subject: Earth Sciences
Supraglacial pond evolution in the Everest region, central Himalaya, 2015-2018.
Published: 2019-01-15
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Supraglacial ponds are characteristic of debris-covered glaciers and can greatly enhance local melt rates. They can grow rapidly and coalesce to form proglacial lakes, presenting a major hazard. Here, we use Sentinel-2A satellite imagery (10 m) to quantify the spatiotemporal changes of 6,425 supraglacial ponds for 10 glaciers in Everest region of Nepal between 2015 and 2018. During the study [...]
A new crustal fault formed the modern Corinth Rift
Published: 2019-01-11
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
This review shows how collective analysis of morphotectonic elements on uplifting rift margins can constrain the mechanical behaviour of continents during early rifting. This is shown for the modern Corinth Rift, one of the fastest-extending and most seismically active continental regions worldwide. We reconstruct the growth of the normal fault system that accommodates most of the rift strain and [...]
Forearc high uplift by lower crustal flow during growth of the Cyprus-Anatolian margin
Published: 2019-01-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
We present a model for the dynamic formation of the forearc high of southern Anatolia where sedimentation in the forearc basin leads to thermally-activated deformation in the lower crust. Our thermo-mechanical models demonstrate that forearc sedimentation increases the temperature of the underlying crust by “blanketing” the heat flux and increasing Moho depth. Deformation switches from frictional [...]
Geometry of flexural uplift by continental rifting in Corinth, Greece
Published: 2019-01-10
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
Understanding early rifting of continental lithosphere requires accurate descriptions of up-bended rift margins and footwalls that correlate in space and time with the elastic flexural uplift that produces them. Here, we characterize the geometry of elastic flexural uplift produced by continental rifting at its spatiotemporal scale in nature (10s km; 10^4-10^6 yr) using geomorphic evidence from [...]
Transient rivers characterize evolving crustal-scale flexure in the Corinth Rift
Published: 2019-01-10
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
Crustal elastic flexure on the flanks of rift-forming faults is a key feature to characterize continental rifting processes that can be resolved by means of transient river drainages on rift footwalls. Here we show that the elastic flexure dynamics of the uplifting southern shoulder of the rapidly-extending, asymmetric Corinth Rift (Greece) are recorded in 3D by its fluvial network. We explore [...]
Anticline growth by shortening during crustal exhumation of the Moroccan Atlantic margin
Published: 2019-01-10
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
It is unclear how the crustal-scale erosional exhumation of continental domains of the Moroccan Atlantic margin and the excessive subsidence of its rifted domains affected the Late Jurassic-Early Cretaceous post-rift evolution of the margin. To constrain the km-scale exhumation, we study the structural evolution of the Jbel Amsittene. This anticline is located on the coastal plain of the [...]
Seismic and aseismic fault growth lead to different fault orientations
Published: 2019-01-10
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Orientations of natural fault systems are subject to large variations. They often contradict classical Andersonian faulting theory as they are misoriented relative to the prevailing regional stress field. This is ascribed to local effects of structural or stress heterogeneities and reorientations of structures or stresses on the long-term. To better understand the relation between fault [...]
Cooperative chemical-mechanical interactions during ion exchange promote rotational ordering in hydrated montmorillonite
Published: 2019-01-10
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
Ion exchange in clays plays a major role in water, nutrient, and contaminant storage and transport in clay-rich media including soils, sediments, and suspensions. Here, we show that ion exchange between sodium and potassium in hydrated montmorillonite is a cooperative process that couples ionic transport to interlayer forces that alter mesoscale particle structures. Fluctuations in cation [...]
Correspondence: The Taupo eruption occurred in 232 ± 10 CE, and not later
Published: 2019-01-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
The Taupo eruption deposit is an isochronous marker bed that spans much of New Zealand’s North Island and pre-dates human arrival. Holdaway et al. (2018, Nature Comms 9, 4110) propose that the current Taupo eruption date is inaccurate and that the eruption occurred “…decades to two centuries…” after the published wiggle-match estimate of 232 ± 10 CE (2 s.d.) derived from a tanekaha (Phyllocladus [...]
‘Trapping and binding’: A review of the factors controlling the development of fossil agglutinated microbialites and their distribution in space and time
Published: 2019-01-08
Subjects: Earth Sciences, Geology, Paleobiology, Physical Sciences and Mathematics
Trapping and binding of allochthonous grains by benthic microbial communities has been considered a fundamental process of microbialite accretion since its discovery in popular shallow-marine modern examples (Bahamas and Shark Bay). However, agglutinated textures are rare in fossil microbialites and, thus, the role of trapping and binding has been debated in the last four decades. Recently, [...]
Neoproterozoic glacial origin of the Great Unconformity
Published: 2019-01-07
Subjects: Earth Sciences, Geochemistry, Geology, Glaciology, Physical Sciences and Mathematics
The Great Unconformity, a profound gap in Earths stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great [...]
Characterizing user-defined objects from outcrop and modern system interpretations for stochastic object-based reservoir modelling
Published: 2019-01-07
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Outcrops and modern depositional environments are important analogues for subsurface hydrocarbon-, water- or CO2-sequestration reservoirs, as they supplement limited well- and seismic- data and provide information on connectivity of sandbodies observed in subsurface datasets. Object based modelling is one of a series of methods that is widely used for modelling subsurface facies architecture. A [...]
Structural evolution and medium-temperature thermochronology of central Madagascar: implications for Gondwana amalgamation
Published: 2019-01-07
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Madagascar occupied an important place in the amalgamation of Gondwana and preserves a record of several Neoproterozoic events that are linked to orogenesis of the East African Orogen. In this study, we integrate remote sensing, field data and thermochronology to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic [...]
Development of an inversion method to extract information on fault geometry from teleseismic data
Published: 2019-01-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Teleseismic waveforms contain information on fault slip evolution during an earthquake, as well as on the fault geometry. A linear finite-fault inversion method is a tool for solving the slip-rate function distribution under an assumption of fault geometry as a single or multiple-fault-plane model. An inappropriate assumption of fault geometry would tend to distort the solution due to Greens [...]
Impulsive source of the 2017, Mw =7.3, Ezgeleh, Iran, earthquake
Published: 2019-01-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
On November 12th 2017, a MW =7.3 earthquake struck near the Iranian town of Ezgeleh, close to the Iran-Iraq border. This event was located within the Zagros fold and thrust belt which delimits the continental collision between the Arabian and Eurasian Plates. Despite a high seismic risk, the seismogenic behaviour of the complex network of active faults is not well documented in this area due to [...]