Preprints
Filtering by Subject: Stratigraphy
Evolution of Fluvial Landscapes during the Eocene-Oligocene Transition in Central North America: Reconstructions from Toadstool Geologic Park, Nebraska, U. S. A.
Published: 2024-06-14
Subjects: Earth Sciences, Sedimentology, Stratigraphy
Rivers drive geomorphic change at Earth’s surface by transporting sediment from mountains to sedimentary basins. They are sensitive to changes in water and sediment flux driven by tectonism, climatic perturbation and or volcanism. We characterized changes in fluvial landscapes during a major Cenozoic cooling event, the Eocene-Oligocene Transition (EOT) at 33.9 Ma. The EOT is characterized by a [...]
Paleohydrology of North American Catchments and Rivers at the Onset of the Eocene-Oligocene Climate Transition: Reconstructions from Fluvial Strata of the White River Group, Toadstool Geologic Park, Nebraska
Published: 2024-06-14
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy
Member of the Brule Formation of the White River Group at Toadstool Geologic Park in Nebraska. Our approach combined descriptive and quantitative methods to reconstruct river flow, sediment transport, channel dynamics, floodplain behavior, and catchment-scale moisture variability and ecosystem function. We found that rivers were ephemeral, with peak flow depths and widths of approximately 2.5 m [...]
Bayesian Inversion with TimeOptMCMC
Published: 2024-05-16
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Statistical Methodology, Stratigraphy
TimeOptMCMC (Meyers and Malinverno, 2018) is a Bayesian approach for evaluating cyclostratigraphic records that quantitatively links geologic data with astronomical theory. This manuscript provides an introductory guide for conducting a TimeOptMCMC Bayesian inversion, following the approach of Meyers and Malinverno (2018). The purpose of this guide is to help users identify an appropriate data [...]
The fate of bars in braided rivers
Published: 2024-05-05
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Ancient river deposits are important archives of past landscape conditions on planetary surfaces. On Earth, they host valuable groundwater, energy resources, and carbon-storage potential. Reconstructing details of paleochannel forms and movements refines our understanding of the controls on river behavior under different climate, landcover, and tectonic conditions, and improves predictions and [...]
The potential of terrestrial and aquatic molluscs for the temporal analysis of Deckenschotter deposits and younger Quaternary sediments from the Swiss Plateau
Published: 2024-05-02
Subjects: Earth Sciences, Geology, Geomorphology, Paleobiology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Soil Science, Stratigraphy, Terrestrial and Aquatic Ecology
Evolution and architecture of an exhumed ocean-facing coarse-grained submarine canyon fill, Baja California, Mexico
Published: 2024-04-15
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy, Tectonics and Structure
Present day submarine canyons are active conduits for large volumes of sediment, carbon, and pollutants from continents to oceans. However, the evolution of submarine canyons over geological timescales remains poorly understood due to their erosional nature and low preservation potential. The Late Cretaceous Punta Baja Formation represents a well-preserved submarine canyon-fill on a [...]
WITHDRAWN: The potential of terrestrial and aquatic molluscs for the temporal analysis of Deckenschotter deposits and younger Quaternary sediments from the Swiss Plateau
Published: 2024-02-08
Subjects: Earth Sciences, Geology, Geomorphology, Paleobiology, Paleontology, Sedimentology, Stratigraphy
An aminostratigraphy for the Quaternary of the Swiss Plateau
Published: 2024-02-08
Subjects: Analytical Chemistry, Earth Sciences, Geochemistry, Other Earth Sciences, Stratigraphy
Here we develop an amino acid chronology to help establish a dated sequence for the important Early Pleistocene Höhere and Tiefere Deckenschotter lithostratigraphic units, as well as other Quaternary deposits from the Swiss Plateau. Age discrimination is possible between the Quaternary sites from the Swiss Plateau in six different biominerals: Bithynia opercula, shell fragments from Fruticola, [...]
Facies models for rocky shorelines and their application to transgressed basement highs in the North Sea.
Published: 2024-01-28
Subjects: Earth Sciences, Geology, Geomorphology, Sedimentology, Stratigraphy
Rocky shorelines form where basement highs are eroded and flooded during marine transgressive events. Despite the Mesozoic North Sea rift generated numerous platform margins and rotated fault blocks which acted as basement highs, rocky shoreline deposits have not been previously reported. In the rock record rocky shoreline deposits are usually represented by thin conglomerates overlying major [...]
River Floodplains, Organic Carbon, and Paleoclimate: How River Dynamics Impart Biases in the Biogeochemical Climate Record of Terrestrial Landscapes
Published: 2024-01-28
Subjects: Earth Sciences, Geochemistry, Geomorphology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
River floodplains can be both sources and sinks for organic carbon. In the sedimentary record, geochemical signatures of terrestrial water availability record climate and ecology along river corridors in deep time. However, paleoenvironmental reconstructions are often confounded by the complex dynamics of organic carbon residence, entrainment, and deposition in a fluvial system. As alluvial [...]
Will the ‘Anthropocene’ finally be formalized?
Published: 2023-12-08
Subjects: Geology, Stratigraphy
A proposal for the formalization of the ‘Anthropocene’ as a new geological epoch following the Holocene has just been submitted (31 October 2023) to the International Commission on Stratigraphy (ICS). This proposal, prepared by the Anthropocene Working Group (AWG) after 13 years of discussions, places the beginning of the ‘Anthropocene’ in the mid-20th century, and considers that the [...]
Downsystem Grain-Size Trends and Mass Balance of an Ancient Wave-Influenced Sediment Routing System: Middle Jurassic Brent Delta, Northern North Sea, Offshore UK and Norway
Published: 2023-11-14
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
We reconstruct upsystem-to-downsystem grain-size variations in the sediment routing systems of the data-rich Middle Jurassic Brent Group of the northern North Sea, using published stratigraphic, thickness, palaeogeographic, provenance and age constraints combined with representative core and wireline-log data. Facies associations provide a textural proxy for gravel, sand and mud grain-size [...]
Changes in mesophotic carbonate-platform export across the end of the last glacial cycle (Saya de Malha Bank, western Indian Ocean)
Published: 2023-11-07
Subjects: Biogeochemistry, Geochemistry, Natural Resources and Conservation, Other Earth Sciences, Other Environmental Sciences, Paleobiology, Sedimentology, Stratigraphy
The export of neritic material from the top of carbonate platforms is a key process in the construction of their slopes. However, our knowledge of the supply pattern of materials from platforms is dominantly based on platforms lying in the euphotic zone during the present sea-level highstand. This is a somewhat biased perspective as through geological time not all platforms were euphotic. The [...]
Transgression–regression cycles drive correlations in Ediacaran–Cambrian rock and fossil records
Published: 2023-11-07
Subjects: Earth Sciences, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Statistical Methodology, Statistics and Probability, Stratigraphy
Strata of the Ediacaran Period (635–538.8 Ma) yield the oldest known fossils of complex, macroscopic organisms in the geologic record. These “Ediacaran-type” macrofossils (known as the Ediacaran biota) first appear in mid-Ediacaran strata, experience an apparent decline through the terminal Ediacaran, and directly precede the Cambrian (538.8–485.4 Ma) radiation of animals. Existing hypotheses for [...]
Fluvial reworking eliminates small craters, but does not meaningfully bias the Mars interbedded-crater record
Published: 2023-10-31
Subjects: Geomorphology, Planetary Geomorphology, Planetary Sedimentology, Sedimentology, Stratigraphy
Interpreting the structures, morphology, and chemistry of the exposed stratigraphic record on Mars is complicated by ancient surface processes that have variably removed parts of the record. Previous research has used the lack of smaller craters (<50 m diameter) interbedded with fluvial deposits to constrain atmospheric pressure when rivers were active on Mars; the notion being that higher [...]