Search results for "Feature"
showing 10 items of 4091 documents
A tale of two gorges: Late Quaternary site formation and surface dynamics in the Mula basin (Murcia, Spain)
2018
Abstract We present a case-study in Palaeolithic archaeology focusing on formation processes at cave- and rock-shelter-sites in a Mediterranean context and on the correlation between site deposits, Quaternary surface sediments and the morphology of the surrounding land. We study three sites located in the basin of River Mula (Murcia, Spain): the cave-site of Cueva Anton and the rock-shelters of Finca Dona Martina and Abrigo de la Boja, in the Rambla Perea valley. They are examined through an integrated geoarchaeological approach that takes into account geomorphological, stratigraphic and soil micromorphological data. The three sites are found within a short distance and cover similar time s…
Late Quaternary palaeoenvironmental reconstruction of sediment drift accumulation in the Malta Graben (central Mediterranean Sea)
2018
The Malta Graben is a deep tectonic depression in the Sicily Channel, bounded by NW-SE normal faults and filled by thick Pliocene-Quaternary deposits. A previous analysis of a giant piston core (LC09) from the Malta Graben had revealed a wide range of sedimentary features (carbonate turbidites, bioturbated mud and scours), although the chronostratigraphic constraint of the stacking pattern has remained elusive. After establishing a reliable chronological framework based on seven radiocarbon dates for a shorter core from the Malta Graben (ANSIC03-735), a down-core analysis of planktonic foraminifer and coccolith abundance, stable isotopes and sediment grain size was carried out. Since the la…
The relationships between soft-sediment deformation structures and synsedimentary extensional tectonics in Upper Triassic deep-water carbonate succes…
2016
Abstract We describe soft-sediment deformation structures into the Upper Triassic cherty limestone outcropping in the Pizzo Lupo section (Central Sicily, Italy), pertaining to the deep-water palaeodomain of the Southern Tethyan margin. In the study section, mainly consisting of thin-bedded mudstone/marl alternations with bedded chert intercalations, some lithofacies have been separated on the basis of the abundance of the calcium carbonate/clay content and the overall textural features. The deformational structures, displaying different deformational styles as folded and faulted beds, disturbed layers, clastic dikes, and slumps occur mainly in the deformed horizons that involve marl-dominat…
Marine Early Triassic Actinopterygii from Elko County (Nevada, USA): implications for the Smithian equatorial vertebrate eclipse
2017
AbstractThe Early Triassic vertebrate record from low paleolatitudes is spotty, which led to the notion of an ‘equatorial vertebrate eclipse’ during the Smithian. Here we present articulated ray-finned fishes (Actinopterygii), collected from the marine Lower Triassic Thaynes Group at three new localities in Elko County (Nevada, USA), which were deposited within the equatorial zone. From the Smithian of the Winecup Ranch, we describe two partial skulls of the predatory actinopterygianBirgeria(Birgeriidae), attributed toB.americananew species andBirgeriasp.Birgeria americanan. sp. is distinguished from other species by a less reduced operculogular series. With an estimated total length of 1.7…
Transient metazoan reefs in the aftermath of the end-Permian mass extinction
2011
5 pages; International audience; Recovery from the devastating Permian-Triassic mass extinction about 252 million years ago is usually assumed to have spanned the entire 5 million years of the Early Triassic epoch1,2. The post-crisis interval was characterized by large-scale fluctuations of the global carbon cycle and harsh marine conditions, including a combination of ocean acidification, euxinia, and fluctuating productivity3. During this interval, metazoan-dominated reefs are thought to have been replaced by microbial deposits that are considered the hallmark of the Early Triassic4-7. Here we use field and microscopic investigations to document Early Triassic bioaccumulations and reefs f…
Direct terrestrial–marine correlation demonstrates surprisingly late onset of the last interglacial in central Europe
2011
AbstractAn interdisciplinary study of a small sedimentary basin at Neumark Nord 2 (NN2), Germany, has yielded a high-resolution record of the palaeomagnetic Blake Event, which we are able to place at the early part of the last interglacial pollen sequence documented from the same section. We use this data to calculate the duration of this stratigraphically important event at 3400 ± 350 yr. More importantly, the Neumark Nord 2 data enables precise terrestrial–marine correlation for the Eemian stage in central Europe. This shows a remarkably large time lag of ca. 5000 yr between the MIS 5e ‘peak’ in the marine record and the start of the last interglacial in this region.
Structure and evolution of a Messinian mixed carbonate-siliciclastic platform: the role of evaporites (Sorbas Basin, South-east Spain).
2010
36 pages; International audience; The Sorbas Member is a late Messinian complex sedimentary systemthat formed immediately following deposition of the Messinian evaporites in the Sorbas Basin (South-east Spain). This work describes the sequence architecture and facies organization of a continuous kilometre long, alluvial fan to open platform transect near the village of Cariatiz in the north-east of the basin. The postevaporitic Cariatiz platform was a mixed carbonate-siliciclastic system composed of four intermediate-frequency, fifth-order depositional sequences (Depositional Sequences 1 to 4) arranged in an overall prograding trend. The intense fracturing and brecciation of these deposits …
Trilobites from the Red Fauna (latest Emsian, Devonian) of Hamar Laghdad, Morocco and their biodiversity
2018
36 pages; International audience; Trilobites are widespread in Early Devonian deposits of north Gondwana; some of the most emblematic ones were collected from the famous latest Emsian (Early Devonian) mudmound locality Hamar Laghdad in south-eastern Morocco. This locality is famous for its trilobites, especially for the conspicuous red-coloured remains of phacopid trilobites with often greenish eyes. Here, we present a taxonomic revision of the previously described trilobites from the so-called Red Fauna of Hamar Laghdad. We introduce the new taxa Harpes hamarlaghdadensis n. sp. and Morocops davidbrutoni n. sp. Phacopids dominate the trilobite assemblage from the Red Cliff at Hamar Laghdad …
Discovery of an Autunian macroflora and lithostratigraphic re-investigation on the western border of the Lodève Permian basin (Mont Sénégra, Hérault,…
2013
11 pages; International audience; Re-investigation of the western edge of the Lodève basin allows reassignment of one sandstone-conglomerate formation previously identified as "terminal Stephanian" to Early Autunian. The existence of two unconformable (Stephanian and Autunian) megasequences, separated by a sedimentary gap, which had been rejected, is thus re-affirmed. The authors also found, less than 20 m above the basal Autunian conglomerate, a macroflora with taxa characteristic of the famous Tuilières flora from a site, located in the eastern part of the basin near Lodève, in the Grey Autunian group. This confirms that the new Mont Sénégra fossiliferous beds belong to the Lower Autunian…
Raw material, gestures, artefacts. An approach to the work of bone and ivory in the Iron Age in the Iberian peninsula
2018
Abstract This work seeks to give visibility to the industry of hard animal materials that is documented during the Iron Age in the Iberian peninsula. We focus on the analysis of three common artefacts within the bone and ivory industry in the Iberian culture (between the 6th to the 1st Century BC): pins, perforated plates and combs. We have studied these objects from a technological point of view, thanks to a series of experimental work carried out in order to meet different operational chains, necessary to manufacture each one of these items and tools that could be used for this purpose. So, we searched the archaeological tool models to work bone and ivory, and whenever it has been possibl…