Filtering by Subject: Stratigraphy

Downward-propagating eruption following vent unloading implies no direct magmatic trigger for the 2018 lateral collapse of Anak Krakatau

Kyra S. Cutler, Sebastian Watt, Mike Cassidy, et al.

Published: 2021-12-18
Subjects: Earth Sciences, Stratigraphy, Volcanology

The lateral collapse of Anak Krakatau volcano, Indonesia, in December 2018 highlighted the potentially devastating impacts of volcanic edifice instability. Nonetheless, the trigger for the Anak Krakatau collapse remains obscure. The volcano had been erupting for the previous six months, and although failure was followed by intense explosive activity, it is the period immediately prior to collapse [...]

Hermann Löns’ “Quintär” – an early approach to the geological stratigraphy of the Age of Humans and its significance in geosciences

Jahn Jochen Hornung

Published: 2021-12-16
Subjects: Earth Sciences, Geology, Other Earth Sciences, Stratigraphy

In 1908, Hermann Löns outlined the concept of a Quintär” (“Quintary period”) to describe geological and biological manifestations of the Age of Humans. His definition of the “Quintary” consisted of two components: a lithostratigraphic (“Quintary deposits” or “Quintary stratum”), and a faunistic (“Quintary fauna”) one. With a view on the stratigraphic component, Löns already anticipated the [...]

WlCount: Geological lamination detection and counting using an image analysis approach

Fabio Oriani, Pauline C Treble, Andy Baker, et al.

Published: 2021-11-08
Subjects: Earth Sciences, Longitudinal Data Analysis and Time Series, Speleology, Stratigraphy

The manual identification and count of laminae in layered textures is a common practice in the study of geological records, which can be time consuming and carry large uncertainty for dense or disturbed lamina textures. We present here a novel image analysis approach to detect and count laminae in geoscientific imagery, called WlCount. Based on Dynamic Time Warping and Wavelet analysis, WlCount [...]

Reproducibility in subsurface geoscience

Michael J. Steventon, Chris Jackson, Mark Ireland, et al.

Published: 2021-10-26
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Environmental Education, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mineral Physics, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Paleobiology, Paleontology, Sedimentology, Soil Science, Speleology, Stratigraphy, Sustainability, Tectonics and Structure, Volcanology, Water Resource Management

Reproducibility, the extent to which consistent results are obtained when an experiment or study is repeated, sits at the foundation of science. The aim of this process is to produce robust findings and knowledge, with reproducibility being the screening tool to benchmark how well we are implementing the scientific method. However, the re-examination of results from many disciplines has caused [...]

Sharp-based, mixed carbonate-siliciclastic shallow-marine deposits (upper Miocene, Betic Cordillera, Spain): the record of ancient transgressive shelf ridges?

Miquel Poyatos-Moré, Fernando García-García, Francisco J. Rodríguez-Tovar, et al.

Published: 2021-10-23
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy

Isolated sharp-based sedimentary bodies in shelf settings can develop via the reworking of regressive deposits during transgressions. An example of these are shelf ridges, formed under a wide range of processes, and widely studied due to their high reservoir potential. However, there is still a lack of examples in mixed (carbonate-siliciclastic) successions. This study presents an outcrop example [...]

Sedimentary response to current and nutrient regime rearrangement in the Eastern Mediterranean Realm during the early to middle Miocene (southwestern Cyprus)

Or M. Bialik, Jesús Reolid, Denise Kulhanek, et al.

Published: 2021-10-11
Subjects: Sedimentology, Stratigraphy

During the early and middle Miocene, the Mediterranean had become a restricted marginal marine sea with diminishing and ultimate loss of connectivity to the Indian Ocean. This dramatically changed the heat, energy, freshwater and nutrient budgets across the Mediterranean and most notably in its eastern basin. While one of the most prominent lines of evidence of this change in the Eastern [...]

The Effect of Formation Processes on The Frequency of Palaeolithic Cave Sites in Semi-Arid Zones: Insights From Kazakhstan

Aristeidis Varis, Christopher Miller, Patrick Cuthbertson, et al.

Published: 2021-10-01
Subjects: Earth Sciences, Geomorphology, Other Environmental Sciences, Physical Sciences and Mathematics, Sedimentology, Social and Behavioral Sciences, Speleology, Stratigraphy

Central Asian caves with Palaeolithic deposits are few but they provide a rich record of human fossils and cultural assemblages that has been used to model Late Pleistocene hominin dispersals. However, previous research has not yet systematically evaluated the formation processes that influence the frequency of Palaeolithic cave sites in the region. To address this deficiency, we combined field [...]

Early Pliocene Marine Transgression into the Lower Colorado River Valley, Southwestern USA, by Re-Flooding of a Former Tidal Strait

Rebecca Dorsey, Juan Carlos Braga Alarcón, Kevin Gardner, et al.

Published: 2021-09-29
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure

Marine straits and seaways are known to host a wide range of sedimentary processes and products, but the role of marine connections in the development of large river systems remains little studied. This study explores a hypothesis that shallow marine waters flooded the lower Colorado River valley at ~ 5 Ma along a fault-controlled former tidal straight, soon after the river was first integrated [...]

Safety and Belonging in the Field: A Checklist for Educators

Sarah E Greene, Gwen S. Antell, Jake Atterby, et al.

Published: 2021-08-19
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Cosmochemistry, Earth Sciences, Education, Environmental Education, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Environmental Studies, Fresh Water Studies, Geochemistry, Geographic Information Sciences, Geography, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Higher Education, Human Geography, Hydrology, Life Sciences, Meteorology, Mineral Physics, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Nature and Society Relations, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Other Geography, Other Oceanography and Atmospheric Sciences and Meteorology, Other Planetary Sciences, Outdoor Education, Paleobiology, Paleontology, Physical and Environmental Geography, Physical Sciences and Mathematics, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Geology, Planetary Geomorphology, Planetary Geophysics and Seismology, Planetary Glaciology, Planetary Hydrology, Planetary Mineral Physics, Planetary Sciences, Planetary Sedimentology, Remote Sensing, Sedimentology, Social and Behavioral Sciences, Soil Science, Spatial Science, Speleology, Stratigraphy, Sustainability, Tectonics and Structure, Volcanology, Water Resource Management

Ensuring taught fieldwork is a positive, generative, collective, and valuable experience for all participants requires considerations beyond course content. To guarantee safety and belonging, participants’ identities (backgrounds and protected characteristics) must be considered as a part of fieldwork planning and implementation. Furthermore, getting fieldwork right is an important step in [...]

The role of surface processes in basin inversion and breakup unconformity

Luke Mondy, Patrice F Rey, Guillaume Duclaux

Published: 2021-08-03
Subjects: Earth Sciences, Geology, Stratigraphy, Tectonics and Structure

At divergent plate boundaries, extensional tectonics lead to subsidence, continental rifting and the formation of continental margins. Yet, within this extensional context, transient compressional structures (stress inversion) and phases of uplift (depth inversion) are frequently recorded with no corresponding change in plate motion. Changes in gravitational potential energy during the rifting [...]

Stylolites and stylolite networks as primary controls on the geometry and distribution of carbonate diagenetic alterations

Enrique Gomez-Rivas, Juan Diego Martín-Martín, Paul D. Bons, et al.

Published: 2021-07-18
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy, Tectonics and Structure

There is an ongoing debate on whether stylolites act as barriers or conduits for fluids, or even play no role in terms of fluid transport. This problem can be tackled by examining the spatial and temporal relationships between stylolites and other diagenetic products at multiple scales. Using the well-known Lower Cretaceous Benicàssim case study (Maestrat Basin, E Spain), we provide new field and [...]

Machine learning thermobarometry and chemometry using amphibole and clinopyroxene: a window into the roots of an arc volcano (Mount Liamuiga, Saint Kitts)

Oliver John Higgins, Tom Sheldrake, Luca Caricchi

Published: 2021-07-04
Subjects: Earth Sciences, Geochemistry, Mineral Physics, Stratigraphy, Volcanology

The physical and chemical properties of magma govern the eruptive style and behaviour of volcanoes. Many of these parameters are linked to the storage pressure and temperature of the erupted magma, and melt chemistry. However, reliable single-phase thermobarometers and chemometers which can recover this information, particularly using amphibole chemistry, remain elusive. We present a suite of [...]

Channel, dune and sand sheet architectures of strait-adjacent deltas

Daan Beelen, Lesli Joy Wood, Mohamed Najib Zaghloul, et al.

Published: 2021-06-17
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy

Sea strait geographies amplify tidal currents, which can result in the formation of tidal strait deposits with a symmetrical facies arrangement. It can be problematic to distinguish such confined tidal strait deposits from strait systems that developed in less constricted settings. To push a more robust differentiation between the confined tidal strait model and a model for less constricted tidal [...]

Spatial and morphometric relationships of submarine landslides offshore west and southwest Iberia

Davide Gamboa, Rachid Omira, Pedro Terrinha

Published: 2021-06-08
Subjects: Earth Sciences, Geology, Geomorphology, Sedimentology, Stratigraphy

Submarine landslides are ubiquitous geohazards in marine environments occurring at multiple scales. Increasing efforts have been made to catalogue and categorise submarine landslides in comprehensive databases, aiming to better understand their preconditioning and trigger factors. Using the recently compiled, open-access MAGICLAND dataset, we investigate the distribution and morphometric trends [...]

Spatial characteristics and kinematics of precession-driven floodplain aggradation cycles in the lower Eocene Willwood Formation of the Bighorn Basin, Wyoming, USA

Youwei WANG, Timothy Baars, Joep Storms, et al.

Published: 2021-06-07
Subjects: Geology, Sedimentology, Stratigraphy

Interaction of allogenic and autogenic forcing in building alluvial stratigraphy remains a complex subject that is critical for paleoenvironmental and paleoclimate reconstruction and subsurface rock property prediction. Astronomical forcing of alluvial stratigraphy is poorly documented so far as this driver strongly interacts with autogenic and other allogenic processes making it difficult to [...]


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