Search results for "OCA"
showing 10 items of 16426 documents
Evidence of organic contamination in urban soils of Cotonou town (Benin).
2012
14 pages; International audience; In Cotonou (Benin), growth of the population leads to an excessive use of natural resources, inducing organic contaminations. Surface soils collected in the town, were extracted and fractionated by liquid chromatography in three families: aliphatic, aromatic hydrocarbons and polar fractions. Each fraction was characterized by gas chromatography-mass spectrometry. All the results show that an anthropogenic input exists (waste oils). Indeed, aliphatic hydrocarbons have specific markers emphasizing the presence of petrogenic products: UCM (unresolved complex mixture), specific distribution of pentacyclic triterpane. However, specific molecular biomarkers revea…
Holocene climate variability in north-eastern Italy: potential influence of the NAO and solar activity recorded by speleothem data
2012
Abstract. Here we present high-resolution stable isotope and lamina thickness profiles as well as radiocarbon data for the Holocene stalagmite ER 76 from Grotta di Ernesto (north-eastern Italy), which was dated by combined U-series dating and lamina counting. ER 76 grew between 8 ka (thousands of years before 2000 AD) and today, with a hiatus from 2.6 to 0.4 ka. Data from nine meteorological stations in Trentino show a significant influence of the North Atlantic Oscillation (NAO) on winter temperature and precipitation in the cave region. Spectral analysis of the stable isotope signals of ER 76 reveals significant peaks at periods of 110, 60–70, 40–50, 32–37 and around 25 a. Except for the …
Soil features in rookeries of Antarctic penguins reveal sea to land biotransport of chemical pollutants
2017
© The Author(s).
Precise dating of the Middle-to-Upper Paleolithic transition in Murcia (Spain) supports late Neandertal persistence in Iberia
2017
Abstract The late persistence in Southern Iberia of a Neandertal-associated Middle Paleolithic is supported by the archeological stratigraphy and the radiocarbon and luminescence dating of three newly excavated localities in the Mula basin of Murcia (Spain). At Cueva Anton, Mousterian layer I-k can be no more than 37,100 years-old. At La Boja, the basal Aurignacian can be no less than 36,500 years-old. The regional Middle-to-Upper Paleolithic transition process is thereby bounded to the first half of the 37th millennium Before Present, in agreement with evidence from Andalusia, Gibraltar and Portugal. This chronology represents a lag of minimally 3000 years with the rest of Europe, where th…
History of ancient megathrust earthquakes beneath metropolitan Tokyo inferred from coastal lowland deposits
2018
Abstract Metropolitan Tokyo is located directly above a subduction zone that has generated two megathrust earthquakes in the past 300 years. However, the timing of older megathrusts on this margin is poorly understood. In this study, we aim to constrain the timings of past megathrust earthquakes, using coastal stratigraphy, paleoecology, radiocarbon dating and archaeological records from coastal lowlands. An investigation of 13 boreholes in the southern coastal area of metropolitan Tokyo found evidence for 4 m of uplift in a 6000-year period. However, we found that net vertical displacement in the last 1000 years is approximately zero. Results suggest that preservation of usually ephemeral …
Debitage by fracturing in the osseous industry of Cova del Parpalló (Gandía-Valencia, Spain): A preliminary study
2016
Abstract The excavations carried out by L. Pericot from 1929 to 1931 in the Cova del Parpallo documented the Gravettian in the base, a Solutrean layer, and a Magdalenian. This sequences comprise an exceptional assemblage of portable art because of the number of plaquets/objects and the great chronological amplitude. With all this information, Parpallo was included in the reduced list of reference sites to organize the European Upper Paleolithic sequence in the first half of the 20th century. The Magdalenian layers were organized in four phases, following H. Breuil's classical proposal. Changes in bases morphology and decorative topics on osseous points permitted this correlation, identifyin…
The Solutrean - Magdalenian Transition: a view from Iberia
2012
The paper examines the Upper SolutreaneArchaic Magdalenian/Badegoulian succession on the base of lithic and bone tool production, chrono-stratigraphic data and radiocarbon dates from the Cantabrian and Mediterranean regions of Iberia, mainly the areas of Asturias and Valencia (Spain). The discussion considers a reduced number of variables (characteristic stone tools, bone points and decoration techniques) and highlights the elements in common. The analysis concerning the transformation of lithic production at Cova del Parpallo provides new data for the Upper SolutreaneArchaic Magdalenian/ Badegoulian transition.
RE-EVALUATING THE BRONZE AND EARLIEST IRON AGE IN LATVIA: CHANGES IN BURIAL TRADITIONS IN THE LIGHT OF 14C DATES
2020
ABSTRACTUntil recently, there was a lack of radiocarbon (14C) dates from the Bronze and Earliest Iron Age (1800–500–1 BC) burial sites in Latvia. The chronology of the sites was assessed on the basis of archaeological analogies with neighboring regions and typological studies of the rather meagre grave inventory. In order to establish a firm foundation for an absolute chronology of burial sites and to better understand changes in mortuary practices during the period, sequences of samples from various burial sites have been dated. In this paper we report 48 14C dates from 12 different sites and discuss them in the context of previously established archaeological chronologies. 14C reservoir e…
Pollen and non-pollen palynomorph evidence of medieval farming activities in southwestern Greenland
2010
International audience; Radiocarbon dating, pollen and non-pollen palynomorph analyses from a lake core were used to establish the timing and effects of farming activities around Lake Igaliku, Eastern Settlement, Greenland. The absence of agro-pastoral impact before the medieval colonization by Europeans provides an opportunity to understand the development of farming activity in a pristine landscape. The results show that the first phase of clearance and grazing pressure, without the expansion of the Norse apophyte (native plant, in habitats created by humans) Rumex acetosa type, could have occurred in the 9–10th century A.D. The presence of Norse settlers and livestock is clearly recorded…
A mitogenome sequence of an Equus hydruntinus specimen from Late Quaternary site of San Teodoro Cave (Sicily, Italy)
2020
Abstract Equus hydruntinus was a small equid that ranged from the Iberian Peninsula to Middle East. In Italy it has been considered present from the Middle Pleistocene to its extinction in the Middle-Late Holocene. E. hydruntinus shares plesiomorphic traits with other known Pleistocene equids. As a consequence, its classification has always been problematic. Genetic analyses on few fossil remains from Iran and Crimea have revealed that E. hydruntinus was more closely related to extant hemiones. To further investigate its systematic position, using target-enrichment capture and next-generation sequencing, we reconstructed a near complete mitogenome of a specimen from San Teodoro Cave from Si…