Search results for "alluvial"
showing 10 items of 31 documents
La diversité des communautés végétales des forêts alluviales de l’Allier est-elle affectée par l’invasion de l’Érable négundo, du Robinier faux-acaci…
2012
Identifiant ProdInra 270418 SPE EcolDur CT3; Master; L’objectif de notre étude a été d’analyser les effets de l’invasion de 3 espèces végétales (Érable négundo, Robinier faux-acacia, Renouée de Bohême) sur la diversité spécifique et fonctionnelle ainsi que sur la structure et la composition spécifique des communautés végétales des forêts alluviales de l’Allier. Des relevés de végétation ont été réalisés dans des paires de quadrats contiguës, envahis et non envahis par les 3 espèces invasives étudiées et dans 3 habitats envahis des forêts alluviales de l’Allier (Saulaie-peupleraie de niveau topographique haut et bas et Chênaie pédonculée-ormaie). Complémentairement à cette approche, un gradi…
Observations préliminaires à l'étude des remplissages des tombes du Néolithique moyen I de Gurgy "Les Noisats" (Yonne)
2008
This paper presents results of experimental digging and filling of a pit in gravel context. That experimentation is the first step of an integrated analysis about sedimentary dynamic in neolithic burials from Gurgy « Les Noisats » (Yonne, France).
Nouvelles données sur le genre Bragasellus (Crustacea: Isopoda: Asellidae
1996
From now on, the genus Bragasellus Henry & Magniez, 1968 includes 2 oculated and 17 stygobiotic species. As a natural and monophyletic taxonomic unit, we consider it a good genus. Its original area corresponds to the north-west quarter of the Iberian Peninsula. Secondarily, this area has extended eastward, using mainly the alluvial channels of hydrographic systems (Ríos Douro + Ebro and tributaries), finally reaching the underground waters of several Mediterranean rivers. This active expansion is exclusively due to the migration of two stygobiotic sibling species: B. lagari Henry & Magniez, 1973 towards the high basin of the Río Tajo, then downstream to the basins of the Ríos Jucar and Turi…
Relations entre sociétés et environnement en Petite Seine du Mésolithique à la fin du Moyen Âge : nouvelles problématiques et résultats récents d’arc…
2021
Actes du colloque Arkéaube; International audience; This jointly authored paper encompasses several contributions which highlight new issues in environmental archaeology and incorporate palaeo-environmental data from preventiveexcavations. More specifically, it broaches three questions:-The evolution of the environment from the Late Glacial to the present day is analysed using faunal remains (malacofaunae—molluscs, etc.) and botanicalremains (pine trunks) preserved in the alluvial deposits of the river Seine;-Riverside occupations based on reconstructions of the hydrography and hydrographic functioning of the channels documented in the Pont-sur-Seine sector and in Bassée;-The marshes assume…
Utilisation des minéraux lourds comme indicateurs de paléoplacers alluvionnaires diamantifères en République centrafricaine (RCA). Use of heavy miner…
2001
International audience; Le diamant est la première ressource minérale de la République Centrafricaine (RCA). Exclusivement exploité par plusieurs sociétés minières avant 1960, il l'est maintenant de façon artisanale. Avec une production annuelle d'envi-ron 500 000 carats (1 carat = 0,2 g), la RCA est le dixième producteur de diamant (en valeur) dans le monde. Les diamants gemmes (pierres de joaillerie, taillables) représentent 70 à 75 % de la production. Deux principales zones diamantifères présentant une relation spatiale évidente existent en RCA : la Formation de Mouka-Ouadda à l'Est et celle de Carnot à l'Ouest. Ces formations, représentant les 'roches magasins' du diamant, constituent a…
Upper Miocene siliciclastic depositional systems in the central-eastern Sicily basins
2014
Late Quaternary slip rates for the southern Elsinore fault in the Coyote Mountains, southern California from analysis of alluvial fan landforms and c…
2019
Abstract Offset alluvial fans along the Elsinore fault in the south-central Coyote Mountains were studied to resolve an average late Quaternary slip rate for this major western strand of the San Andreas fault system in southern California. Alluvial fans and their offsets were mapped using high-resolution DEMs combined with field observations of fan-surface morphology and the character of the soils developed in each fan remnant. Clast assemblage data was used to determine the source of each alluvial fan upstream of the fault, and U-series dating of pedogenic carbonate was used to estimate minimum ages of the alluvial fan surfaces. Forty U-Th dates on pedogenic carbonate confirm the utility o…
Stratigraphy of the Neoproterozoic Damara Sequence in northwest Namibia: Slope to basin sub-marine mass-transport deposits and olistolith fields
2016
Abstract The Neoproterozoic Damara Sequence (>1000 m thick) is composed of siliciclastic and carbonate rocks that crop out in the Damara Belt, Namibia. In Damaraland (including the Vrede, Bethanis, Austerlitz and Toekoms farms), these rocks were deformed and metamorphosed under greenschist facies (biotite zone) conditions during the Damara Orogeny. The stratigraphy and paleoenvironments of the Damara Sequence rocks are debated by the scientific community. We use field data, including detailed 1:25,000 geological mapping, elaboration of stratigraphic profiles and observation of preserved primary structures, textures and composition, to identify lithofacies and lithofacies associations, and t…
The discovery of a Mycenaean-type tholos tomb in the Bronze Age necropolis of the Gazzi buried floodplain (Messina, Southern Italy): new geological a…
2019
This paper deals with a monument that is, up to this date, unique in Sicily and in the Italian peninsula: the Mycenaean-type tholos tomb of the Gazzi necropolis in Messina. A recent excavation in the alluvial deposits revealed extensive traces of a funerary area with a tholos tomb and several enchytrismos tombs with skeletal remains, presumably dated back to the end of the Early or the initial stage of the Middle(?) Bronze Age. The present multi-disciplinary investigation has been developed to analyse new data related to sediments, building stones and skeletal remains of this funerary area. The stratigraphic succession hosting the necropolis was formed by overbank sediments deposited on the…
Fan Deltas and Floodplains in Valencian Coastal Plains
2018
The Valencian coastal plains are formed at the end of two important mountain systems: the Iberian Mountain Range to the north and the Baetic Mountains to the south. As a result of tectonic and neotectonic activity, several graben have been formed at the foot of these reliefs, which have been filled with Plio-Quaternary deposits. In all the coastal plains a depositional sequence is repeated in which the river deposits -fan deltas and alluvial plains- alternate with lagoons/marshes. Basin dimensions, sediment input, tectonics and neotectonics in the study area all determine the size, style and characteristics of fluvial forms, which in turn, influence the characteristics of the coast. Ephemer…