Search results for "STU"
showing 10 items of 43574 documents
The sedimentary and remote-sensing reflection of biomass burning in Europe
2018
Aim: We provide the first European-scale geospatial training set relating the charcoal signal in surface lake sediments to fire parameters (number, intensity and area) recorded by satellite moderate resolution imaging spectroradiometer (MODIS) sensors. Our calibration is intended for quantitative reconstructions of key fire-regime parameters by using sediment sequences of microscopic (MIC from pollen slides, particles 10-500 µm) and macroscopic charcoal (MAC from sieves, particles > 100 µm). Location: North-south and east-west transects across Europe, covering the mediterranean, temperate, alpine, boreal and steppe biomes. Time period: Lake sediments and MODIS active fire and burned area…
Summer air temperature, reconstructions from the last glacial stage based on rodents from the site Taillis-des-Coteaux (Vienne), Western France.
2014
AbstractThe oxygen isotope composition of phosphate from tooth enamel of rodents (δ18Op) constitutes a valuable proxy to reconstruct past air temperatures in continental environments. This method has been applied to rodent dental remains from three genera, Arvicola sp., Microtus sp. and Dicrostonyx sp., coming from Taillis-des-Coteaux, Vienne, France. This archaeological site contains an exceptionally preserved sedimentary sequence spanning almost the whole Upper Palaeolithic, including seven stratigraphic layers dated from 35 to 17 cal ka BP. The abundant presence of rodent remains offers the opportunity to quantify the climatic fluctuations coeval of the various stages of human occupation…
The history and impacts of farming activities in south Greenland: an insight from lake deposits.
2013
International audience; Agriculture in southern Greenland has a two-phase history: with the Norse, who first settled and farmed the region between 985ad and circa 1450ad, and with the recent reintroduction of sheep farming (1920ad to the present). The agricultural sector in Greenland is expected to grow over the next century as anticipated climate warming extends the length of the growing season and increases productivity. This article presents a synthesis of results from a well-dated 1500-year lake sediment record from Lake Igaliku, south Greenland (61°00′N, 45°26′W, 15m asl) that demonstrates the relative impacts of modern and Norse agricultural activities. Pollen, non-pollen palynomorphs…
Digital and Handcrafting Processes Applied to Sound-Studies of Archaeological Bone Flutes
2016
Bone flutes make use of a naturally hollow raw-material. As nature does not produce duplicates, each bone has its own inner cavity, and thus its own sound-potential. This morphological variation implies acoustical specificities, thus making it impossible to handcraft a true and exact sound-replica in another bone. This phenomenon has been observed in a handcrafting context and has led us to conduct two series of experiments (the first-one using handcrafting process, the second-one using 3D process) in order to investigate its exact influence on acoustics as well as on sound-interpretation based on replicas. The comparison of the results has shed light upon epistemological and methodological…
Evidence of aerial volcanic activity during the Valanginian along the northern Tethys margin.
2009
7 pages; International audience; Stratigraphic measurement and sampling on three sections (Vergol, La Charce, and Montclus) through Valanginian deposits from the Vocontian Basin (southeastern France) reveals the occurrence of centimetre thick ochre-coloured layers, which can be correlated from one section to another. At least twelve of these are identified in sediments dated from the Pertransiens to Furcillata ammonite Zones. These horizons appear similar to previously described Oxfordian and Aptian bentonites, also from the Vocontian Basin. Clay-mineralogical and geochemical data are similar in the Valanginian ochre horizons and their enclosing marls except in one of these that shows a cla…
Environmental and climatic controls of the clay mineralogy of Albian deposits in the Paris and Vocontian basins (France)
2020
18 pages; International audience; High-resolution clay mineral analyses were performed on lower and middle Albian deposits from the Paris and Vocontian basins in order to specify the weathering conditions that prevailed at that time. The clay mineral assemblages are composed of small proportions of chlorite and vermiculitic clays associated with abundant illite, R0 type illite-smectite mixed-layers (smectite) and kaolinite. Clay minerals originated from the physical alteration and chemical weathering of rocks and soils outcropping on the Variscan massifs bordering the studied areas. In the Paris Basin, the covariation of illite and kaolinite suggests the reworking of these latter minerals f…
Ancient DNA from European early neolithic farmers reveals their near eastern affinities.
2010
The first farmers from Central Europe reveal a genetic affinity to modern-day populations from the Near East and Anatolia, which suggests a significant demographic input from this area during the early Neolithic.
Inter-site variability in the season of shellfish collection on the central coast of British Columbia
2013
High-resolution stable oxygen isotope analysis of the bivalve Saxidomus gigantea from shell midden sites was applied to identify seasonal patterns of resource procurement on the central coast of British Columbia, Canada. A total of 90 archaeological shells were examined from eight distinct sites spanning a 4500-year period. Combining micro-growth pattern analysis with high-resolution stable oxygen isotope sampling allows for a precise season of collection to be determined in estuarine bivalves recovered from archaeological sites. The results of the stable oxygen isotope analysis provide insights into seasonally structured harvest of S. gigantea (butter clam), which is associated with differ…
A 2500 year record of natural and anthropogenic soil erosion in South Greenland
2012
International audience; The environmental impact of the Norse landnám in Greenland has been studied extensively. But to date, no study has quantified the soil erosion that Norse agricultural practices are believed to have caused. To resolve this problem, a high resolution sedimentary record from Lake Igaliku in South Greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use. An accurate chronology allows for the estimation of detritic fluxes and their uncertainties. Land clearance and the introduction of grazing livestock by the Norse around 1010 AD caused an acceleration of soil erosion up to 8 mm/century in 1180 AD which is two-fo…
Land use change, soil erosion and alluvial dynamic in the lower Doubs Valley over the 1st millenium AD (Neublans, Jura, France)
2003
International audience; Geochemical and particle size analyses, surface scanning magnetic susceptibility, microscopic charcoal counting and pollen analysis, have been carried out on two cores from the lower Doubs valley in order to reconstruct the land use history. The interpretation of anthropogenic pollen indicators and micro-charcoal deposits is discussed in relation to the lithological variation of sedimentary accumulation and evolution of the settlement. The environmental changes which occurred during the 1st and the 6th century AD reflect the impact of human activities on the landscape in the immediate surroundings of the site. Multiproxy indicators indicate that soil erosion as a con…