Preprints
Filtering by Subject: Sedimentology
Tectonic-Sedimentary Interplay of a Multi-Sourced, Structurally-Confined Turbidite System in a Foreland Basin Setting: The Pennsylvanian Lower Atoka Formation, Ouachita Mountains, USA
Published: 2020-06-19
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Submarine fans deposited in structurally complex settings record important information on basin evolution and tectonic-sedimentary relationships but are often poorly preserved in outcrops due to post-depositional deformation. This study integrates both new field data as well as data compiled from literature to demonstrate the spatial facies variability of the deep-water lower Atoka formation [...]
Sediment redox dynamics in an oligotrophic deep-water lake in Tierra del Fuego: insights from Fe isotopes
Published: 2020-06-10
Subjects: Earth Sciences, Fresh Water Studies, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Fe speciation and Fe isotopes have been widely used to reconstruct past basin dynamics and water redox conditions. However, sedimentation and early diagenesis of such proxies eventually alter any primary climate signal. In this work, we disentangled the processes occurring at the redox front below the sediment-water interface of a ventilated deep-water lake (Lago Fagnano, Argentina/Chile). A [...]
Architecture and controls of thick, intensely bioturbated, storm-influenced shallow-marine successions: an example from the Jurassic Neuquén Basin (Argentina)
Published: 2020-06-05
Subjects: Earth Sciences, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
Thick (>100 m-thick), highly bioturbated storm-influenced shallow-marine deposits are not frequent in the stratigraphic record, but they tend to be unusually common in aggradational to retrogradational successions. Individual storm-event beds have typically low preservation in these successions, yet depositional settings are characterized on the basis of storms processes. We present a [...]
Advective sorting of silt by currents: a laboratory study
Published: 2020-05-27
Subjects: Earth Sciences, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Accumulations of fine sediments along continental shelf and deep-sea bathymetric contours, known as contourite drifts, form a sedimentary record that is dependent on oceanographic processes such as ocean-basin-scale circulation. A tool used to aid in interpretation of such deposits is the sortable silt hypothesis, which suggests that the mean size of the sortable silt (silt from 10-63 µm) within [...]
Fault-controlled base-of-scarp deposits
Published: 2020-05-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
The term base-of-scarp is proposed for those submarine deposits controlled by a fault and physically disconnected from their more proximal counterpart located on the footwall, although genetically linked to it. These systems differ from conventional fault-controlled deltas, such as shoal- and Gilbert-type, because they are entirely subaqueous and lack equilibrium morphology — a steady-state in [...]
Holocene tephrochronology of Kerguelen Archipelago, Subantarctic Indian Ocean
Published: 2020-05-20
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology
Up to now, no geochemical or geochronological data has been published about Holocene volcanic activity on the Kerguelen Archipelago. Here we present the first continuous Holocene chronology of volcanic eruptions on the archipelago. We compared sedimentological, geochronological and geochemical data from two lake sediment cores taken in two different depocenters of Lake Armor, located ca. 70 km [...]
Macroscopic flow disequilibrium over aeolian dune fields
Published: 2020-05-08
Subjects: Atmospheric Sciences, Earth Sciences, Geomorphology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Aeolian dune fields are self-organized patterns formed by wind-blown sand. Dunes are topographic roughness elements that impose drag on the atmospheric boundary layer (ABL), creating a natural coupling between form and flow. While the steady-state influence of drag on the ABL is well studied, non-equilibrium effects due to roughness transitions are less understood. Here we examine the large-scale [...]
Projections of global delta land loss from sea-level rise in the 21st century
Published: 2020-05-06
Subjects: Earth Sciences, Geomorphology, Hydrology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
River deltas will likely experience significant land loss because of relative sea-level rise (RSLR), but predictions have not been tested against observations. Here, we use global data of RSLR and river sediment supply to build a model of delta response to RSLR for 6,402 deltas, representing 86% of global delta land. We validate this model against delta land area change observations from [...]
Setting up the preservation of fluvial channel belts
Published: 2020-04-29
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Subsidence alone is often too slow to create the necessary relief needed to preserve continuous channel belts over 10s of km, as are often observed in outcrops on Earth and Mars, as well as subsurface seismic volumes. However, an alternative source of topographic relief exists along US Gulf of Mexico and SE Atlantic coastal plains, which are regions generally considered flat. Alluvial ridges, [...]
Lateral variability in strain along a mass-transport deposit (MTD) toewall: a case study from the Makassar Strait, offshore Indonesia
Published: 2020-04-18
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Contractional features characterise the toe domain of mass-transport deposits (MTDs). Their frontal geometry is typically classified as frontally-confined or frontally-emergent. However, it remains unclear how frontal emplacement style and contractional strain within an MTD can vary along strike. We use bathymetry and 3D seismic reflection data to investigate lateral variability of frontal [...]
Turbidites, Topography and Tectonics: Evolution of submarine channel-lobe systems in the salt-influenced Kwanza Basin, offshore Angola
Published: 2020-04-07
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Understanding the evolution of submarine channel-lobe systems on salt-influenced slopes is challenging as systems react to seemingly subtle changes in sea-floor topography. The impact of large blocking structures on individual deep-water systems is well documented, but understanding of the spatio-temporal evolution of regionally extensive channel-lobe systems in areas containing modest salt [...]
International disparities in open access practices of the Earth Sciences community
Published: 2020-03-31
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Library and Information Science, Mineral Physics, Other Earth Sciences, Paleobiology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Social and Behavioral Sciences, Soil Science, Speleology, Stratigraphy, Tectonics and Structure, Volcanology
Short communication on international disparities in open access practices of the Earth Sciences community
Shallow-water mudstone architecture and depositional process variability: evidence for heterogeneity at kilometre-scale
Published: 2020-03-30
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Mudstone studies that use a large spacing (>5km) between datapoints provide little insight into the architecture and depositional process variability at kilometre scale. This often leads to the assumption that mudstones are laterally homogenous at kilometre and sub-kilometre scales. To better understand the lateral variability of mudstones at kilometre scale, the Mancos Shale in the eastern [...]
Seismic expression, structure and evolution of flow cells within a mass-transport complex
Published: 2020-03-25
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Mass flows evolve longitudinally during emplacement, but they can also vary laterally by forming discrete, shear zone-bound intraflow cells with different rheological states. Despite being documented in several field and subsurface studies, the controls on the initiation, translation, and cessation of these flow cells remain unclear. We here use five, high-quality post-stack time-migrated (PSTM) [...]
The Last Glacial Maximum Balearic Abyssal Plain Megabed revisited
Published: 2020-03-18
Subjects: Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Megabeds are thick sedimentary layers extending over thousands square kilometres in deep sea basins and are thought to result from large slope failures triggered by major external events. Such deposits have been found in at least three areas of the Mediterranean Sea. Although their discovery dates back to the early 1980s, many questions remain, concerning their initiation, source area, extent, [...]