Search results for "Sedimentary"
showing 10 items of 455 documents
Carbon and Oxygen Isotope Signals from the Callovian–Oxfordian in French Sedimentary Basins
2013
3 pages; International audience; High-resolution carbon and oxygen isotope data from the Paris Basin and the Subalpine Basin (France) are available in a precise biostratigraphic framework for the Callovian-Oxfordian stages. A biostratigraphically well-constrained δ13C curve, derived from bulk carbonates in the Paris Basin and the Subalpine Basin, is provided in order to document carbon-cycle evolution and to serve as a chemostratigraphic reference for the Callovian-Oxfordian in the Tethyan domain. Sea-temperature reconstructions, using diagenetically screened belemnite and oyster data, reveal major climate perturbations at the Middle-Late Jurassic transition.
Biostratigraphy, Chronostratigraphy and Paleonvironmental Reconstruction of the Palermo Historical Centre Quaternary succession
2016
Marine deposits from the Palermo Plain were historically relevant for the Quaternary Period definition. Here we show lithostratigraphic, biostratigraphic and chronostratigraphic data collected on three boreholes in the Palermo historical centre that recovered 36.8, 42.0 and 52.0 metres of sediments overlaying the Numidian Flysch. Marine sedimentary sequences span from the Calabrian Stage (calcareous nannofossil Zone MNN 19d) to the Middle Pleistocene (dominance of medium-sized gephyrocapsids within the MNN 19f Zone) and also include a short Holocene depositional event. Calcareous nannofossil, benthic and planktonic foraminifera assemblages point to a shallow coastal environment, possibly < …
Carbonate slope re‐sedimentation in a tectonically‐active setting (Western Sicily Cretaceous Escarpment, Italy)
2020
Tectonic processes are widely considered as a mechanism causing carbonate platform margin instabilities leading to the emplacement of mass transport deposits and calciturbidites. However, only few examples establishing a clear link between tectonics and re-sedimentation processes are known from the lit- erature. The two-dimensional and three-dimensional wire-cut walls of hun- dreds of quarries extracting ornamental limestones (for example, Perlato di Sicilia) from the Western Sicily Cretaceous Escarpment in Italy expose a series of mass transport deposits. The depositional architecture, spatial facies distri- bution and sedimentary features of these deposits were studied in detail. Thin sec…
Missing Records and Depositional Breaks in French Late Pleistocene Cave Sediments
1993
AbstractCave entrance and rock shelter infillings are positioned within the Pleistocene chronology for three areas of France (northern Alps, Franche-Comté, and Périgord). Despite minor local variations, it is possible to identify regional types with a consistent depositional record over long intervals of time. The interregional variability relates to the frequency and position of the gaps within the infillings. Sites in the northern Alps have not yielded any artifacts older than the Upper Paleolithic (Magdalenı́an), and dated sedimentary sequences do not go back beyond the Older Dryas. More complete sequences in Franche-Comté contain Mousterian industries. Two major gaps occur here, one las…
The early Upper Palaeolithic of Cova de les Cendres (Alicante, Spain)
2019
Abstract This paper presents a synthesis of the Early Upper Palaeolithic of Cova de les Cendres. Points of special attention are the sedimentary and micromorphological characterisation of level XVI, the analysis of the vegetal and animal resources and their incidence on the economy of the Gravettian human groups, and the characterisation of the landscape during this period. Furthermore, the paper offers important information of the lithic and bone assemblages, economic behaviour and radiocarbon dates of sub-levels XVIA and XVIB, related to the Gravettian, and XVIC and XVID, corresponding to the Aurignacian. Finally, the Gravettian and Aurignacian regional contexts in the Mediterranean Basin…
A Cretaceous carbonate escarpment from Western Sicily (Italy): biostratigraphy and tectono-sedimentary evolution
2020
Abstract The presence of a huge carbonate slope of Cretaceous age is recorded in some imbricated thrust sheets from the Maghrebian fold-and-thrust belt cropping out in northwesternmost Sicily (southern Italy). The sedimentological features of this escarpment, named as the Western Sicily Cretaceous Escarpment (WSCE), have been recently described. The present paper aims to provide a detailed bio-chronostratigraphic characterization of the different facies types that occur in the four lithostratigraphic units spanning the whole slope depositional system. The detailed biostratigraphic analysis and correlation of a number of well-exposed sections allowed to differentiate eight informal biozones …
Landscape reconstruction and major flood events of the River Main (Hesse, Germany) in the environs of the Roman fort at Groβkrotzenburg
2020
Abstract Detailed geoarchaeological studies were conducted at the Groβkrotzenburg floodplain (Southern Hesse, Germany) in order to reconstruct the fluvial palaeogeography and search for Roman harbour installations. Another objective was to reconstruct the local flood history based on stratigraphic and geochronological data. Prospection based on electrical resistivity tomography, vibracoring and direct push electrical conductivity logging were carried out to detect and analyze subsurface stratigraphies. Altogether, 6 sediment cores, up to 7 m long, were drilled along transects along and perpendicular to the present course of the River Main. Based on sedimentological and geochemical data, we …
Does glacial environment produce glacial mineral grains? Pro- and supra-glacial Icelandic sediments in microtextural study
2022
Abstract Mineral grains from proglacial and supraglacial sedimentary settings in central south-eastern Iceland are considered in this study and analysed with the use of scanning electron microscope (SEM) techniques. By applying this, it is attempted to answer the key research question of whether quartz grains that come from a glacial-related sedimentary environment are indeed of glacial origin. The study also attempts to provide a linkage between microtextures produced on coarser and finer grains and to verify whether mineral grains from adjacent cryconite holes are similar or different. The preliminary assumption was that the more intense glacial grain record was based on several glacial a…
Depositional mechanism of the upper Pliocene-Pleistocene shelf-slope system of the western Malta Plateau (Sicily Channel)
2021
Abstract A high resolution seismic stratigraphic study of the western edge of the Malta Plateau (central Mediterranean Sea) was conducted to reconstruct the depositional mechanisms of the shelf-slope system since the end of the Messinian salinity crisis (MSC; 5.3 Ma). The accurate interpretation of a large grid of variable-resolution seismic reflection profiles (multichannel and Sub Bottom) allows us to identify and map a Plio-Quaternary sedimentary sequence overlying the Messinian evaporites. The stratal pattern of this sequence is the result of a clinoform prograding system that constitutes the internal structure of a sedimentary shelf developed in a ramp about 2° slope with bathymetries …
Accelerated transgressive processes in a Mediterranean coastal barrier: Subsidence, anthropic action and geomorphological changes since the Little Ic…
2020
Abstract Subsidence, changes in sediment supply and environments, sea storms, current sedimentary deficit and recent anthropic action are factors determining coastal geomorphological processes and evolution of a transgressive Mediterranean coastal barrier. At a longer timescale, the barrier landward migration is partially due to local subsidence of tectonic origin. Peatmarsh remains under seawater at around 100 m from the present-day coastline (4821–4566 and 4874‒4820 cal BP) show evidence of the more advanced position towards the sea of the late Holocene coastal barrier, which has not been preserved. Furthermore, behind the present gravel barrier, wide sandy washover fans dating about 665 …