Filtering by Subject: Stratigraphy

Evolution and architecture of an exhumed ocean-facing coarse-grained submarine canyon fill, Baja California, Mexico

Max Bouwmeester, Ian Kane, David Hodgson, et al.

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WITHDRAWN: The potential of terrestrial and aquatic molluscs for the temporal analysis of Deckenschotter deposits and younger Quaternary sediments from the Swiss Plateau

Nigel Thew

Published: 2024-02-08
Subjects: Earth Sciences, Geology, Geomorphology, Paleobiology, Paleontology, Sedimentology, Stratigraphy

An aminostratigraphy for the Quaternary of the Swiss Plateau

Kirsty Penkman, Nigel Thew, Samantha Presslee, et al.

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.

Josep Maria Puig Lopez, John Howell

Published: 2024-01-29
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

Anjali M Fernandes, Michael T Hren, Virginia B. Smith, et al.

Published: 2024-01-29
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?

Valentí Rull

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

Ikenna Okwara, Gary J Hampson, Alexander C Whittaker, et al.

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)

Or M. Bialik, Christian Betzler, Juan Carlos Braga Alarcón, et al.

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

Daniel C Segessenman, Shanan E Peters

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

Andrew Moodie, Timothy Goudge

Published: 2023-10-31
Subjects: Geomorphology, Planetary Geomorphology, Planetary Sedimentology, Sedimentology, Stratigraphy

Interpreting structures, morphology, and chemistry of the exposed stratigraphic record on Mars is complicated by ancient surface processes that 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 atmospheric [...]

New insights into the Upper Pleistocene directed blast eruption, Popocatépetl volcano, México

R. Marcela Lira Beltrán, Lizeth Caballero, Delphine Sourisseau, et al.

Published: 2023-10-30
Subjects: Geology, Stratigraphy, Volcanology

Volcanic eruptions of the directed blast type can affect areas of hundreds of square kilometres and reach more than 25 km from the crater, as observed in the directed explosions of the Bezymianny (1956) and Mt. St. Helens (1980) volcanoes. These directed eruptions are characterized by powerful explosions with a significant lateral component that can travel at speeds above 100 m/s, which includes [...]

Sediment supply controls on Early Eocene delta sequences (South Pyrenean Foreland Basin; Spain)

Romain Vaucher, Claire Musajo, Jorge E. Spangenberg, et al.

Published: 2023-10-13
Subjects: Climate, Geochemistry, Geology, Sedimentology, Stratigraphy

Sediment supply variations are often overlooked when interpreting depositional sequences, which tend to emphasize changes in accommodation. Here, we focus on a temporally well-constrained shallow-marine succession in the South Pyrenean Foreland Basin to test the control of sediment supply on the development of deltaic sequences during the Early Eocene. We analyzed the paleoenvironmental record [...]

Towards an astrochronological framework for the lower Paleoproterozoic Kuruman and Brockman Iron Formations

Margriet L Lantink, Joshua HFL Davies, Rick Hennekam, et al.

Published: 2023-09-01
Subjects: Earth Sciences, Physical Sciences and Mathematics, Stratigraphy

Recent evidence for astronomical-induced cycles in banded iron formations (BIFs) hints at the intriguing possibility of developing astrochronological, i.e. precise time-stratigraphic, frameworks for the earliest Proterozoic as also reconstructed for parts of the Mesozoic and Paleozoic. The ca 2.47-Ga Kuruman Iron Formation (Griqualand West Basin, South Africa) and Dales Gorge Member of the [...]

Spontaneous Unsteadiness and Sorting in Pyroclastic Density Currents and their Deposits

Pete Rowley, Rebecca Williams, Matthew Johnson, et al.

Published: 2023-08-22
Subjects: Geology, Sedimentology, Stratigraphy, Volcanology

Pyroclastic density currents (PDCs) pose substantial risk to populations living on and around active volcanoes, but their structure and internal dynamics are poorly understood. Much of this understanding is derived from interpretation of their widespread deposits. Scaled experiments are able to probe different conditions, to explore how changing flow dynamics relate to the wide variety of [...]

Eocene (50-55 Ma) greenhouse climate recorded in nonmarine rocks of San Diego, CA, USA

Adrian Broz, Devin Pritchard-Peterson, Sarah Schneider, et al.

Published: 2023-08-08
Subjects: Chemistry, Climate, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Soil Science, Stratigraphy

Nonmarine rocks in sea cliffs of southern California store a detailed record of weathering under tropical conditions millions of years ago, where today the climate is much drier and cooler. This work examines early Eocene (~50-55 million-year-old) deeply weathered paleosols (ancient, buried soils) exposed in marine terraces of northern San Diego County, California, and uses their geochemistry and [...]


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