Preprints
Filtering by Subject: Sedimentology
The Rapa Nui Little Ice Age drought: evidence, potential causes and socioecological impact
Published: 2024-01-12
Subjects: Paleontology, Sedimentology, Terrestrial and Aquatic Ecology
A decade ago, an island-wide drought was proposed to have occurred on Rapa Nui (Easter Island) during the Little Ice Age (LIA). This climatic event was considered to be important for ecological and cultural transformations that occurred on the island during the 16th and 17th centuries. Independent multiproxy paleoecological and paleoclimatic evidence produced in the last years supports the [...]
PHOTOMOB: AUTOMATED GIS METHOD FOR ESTIMATION OF FRACTIONAL GRAIN DYNAMICS IN GRAVEL BED RIVERS. PART 1: GRAIN SIZE
Published: 2023-12-06
Subjects: Earth Sciences, Environmental Monitoring, Geomorphology, Hydrology, Sedimentology, Water Resource Management
Particle entrainment intensity is spatially and temporally variable, making it a complex phenomenon to measure. This paper is the first of a pair, in which we present an automated image processing procedure (PhotoMOB) for monitoring the mobility/stability of gravel river beds. The method is based on local comparison of the shape of the grains identified at the same coordinates between successive [...]
PhotoMOB: Automated GIS method for estimation of fractional grain dynamics in gravel bed rivers. Part 2: Bed stability and fractional mobility
Published: 2023-12-06
Subjects: Earth Sciences, Environmental Monitoring, Geomorphology, Hydrology, Sedimentology, Water Resource Management
Bed mobility and stability are spatially and temporally variable, making it a complex phenomenon to study. This paper is the second of a pair, in which we present an automated image processing procedure for monitoring the mobility/stability of gravel river beds. The method is based on local comparison of the shape of the grains identified at the same coordinates between successive photos to [...]
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 [...]
How agriculture, droughts and diseases shaped the island environments of Remote Oceania over the last Millennium
Published: 2023-11-10
Subjects: Paleontology, Sedimentology
Over the past millennium, the Pacific Islands have experienced significant transformations, caused by different waves of human settlement and climatic variability. However, the paucity of archeological records coupled with the complex climatic setting of the tropical Pacific hinders our understanding of past environmental and societal changes. In this study, we employ a multi-proxy approach on [...]
Wetter climate favouring early Lapita horticulture in Remote Oceania
Published: 2023-11-10
Subjects: Paleontology, Sedimentology
The islands of Remote Oceania were among the last places on Earth colonised by humans. Lapita seafarers carrying with them an extensive root-tuber-tree crop complex and domestic animals, rapidly transformed nearly all of these previously unoccupied islands. However, the timing of initial Lapita settlements and the early introduction of horticulture remain a matter of debate as significant changes [...]
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 [...]
Sediment supply controls on Early Eocene delta sequences (South Pyrenean Foreland Basin; Spain)
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 [...]
Complementary classifications of aeolian dunes based on morphology, dynamics, and fluid mechanics
Published: 2023-10-03
Subjects: Earth Sciences, Fluid Dynamics, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Planetary Geomorphology, Planetary Sciences, Sedimentology
Dunes form where winds blow over a bed of mobile sediment grains – conditions that are common in our solar system. On Earth, dunes abound in arid continental interiors and along sandy coastlines. Dune fields have also been recognized on Venus, Mars, Saturn's moon Titan, and Pluto. In response to the different boundary conditions and other environmental forcings, dunes adopt a rich diversity [...]
Spontaneous Unsteadiness and Sorting in Pyroclastic Density Currents and their Deposits
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 [...]
Application of the authigenic 10Be/9Be dating to constrain the age of a long-lived lake and its regression in an isolated intermontane basin: The case of Late Miocene Lake Turiec, Western Carpathians
Published: 2023-07-31
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
The depositional record of intermontane basins provides a valuable archive of the temporal evolution of orogenic belts; their common isolated nature may, however, hinder the efficient usage of standard approaches to constrain the age of a basin fill. In this paper the authigenic 10Be/9Be dating method is employed and tested to construct an age model of the existence and regression of Lake Turiec, [...]
Sedimentology and sequence stratigraphy of shallow-marine, coarse-grained siliciclastic deposits in the southern Utsira High: the Late Jurassic intra-Draupne Formation sandstones in the Johan Sverdrup Field (Norwegian North Sea).
Published: 2023-06-30
Subjects: Earth Sciences, Geology, Sedimentology, Stratigraphy, Tectonics and Structure
Thin, condensed coarse-grained shallow-marine successions can be difficult to describe and interpret, especially in the subsurface because they commonly lack finer grained intervals which are typically associated with sequence stratigraphic surfaces. This lack of mudstones and siltstones means that they also typically make excellent reservoir intervals. The Oxfordian to Volgian intra-Draupne [...]
Seismic Stratigraphy of Contourite Drift Deposits Associated with the Loop Current on the Eastern Campeche Bank, Gulf of Mexico
Published: 2023-06-08
Subjects: Geophysics and Seismology, Oceanography, Sedimentology, Stratigraphy
The Loop Current is a key component of global circulation via the northward transport of warm, salty water and an important influence on Gulf of Mexico hydrography. Understanding how the Loop Current will respond to ongoing anthropogenic warming is critically important, but the history of the Loop Current is poorly known. Here, we present the results of a high resolution (3-8 m) multichannel [...]