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Suitability of biogenic carbonate of Lithospermum fruits for C 14 dating

Suitability of biogenic carbonate of Lithospermum fruits for C 14 dating
Action biogène ; Archéologie ; Carbonate ; Datation ; Datation C 14 ; Fruits ; Microstructure ; Quaternaire
Archaeology ; Biogenic process ; C 14 dating ; Carbonate ; Dating ; Fruit ; Microstructure ; Quaternary
The AA. present an extended set of C 14 dates on the carbonate fraction of Lithospermum fruits from 4 modern and 11 fossil samples. The data suggest that biogenic carbonate from the fruits of Lithospermum represents suitable material for radiocarbon
dating. Biogenic carbonate of Lithospermum fruits, like that of Celtis, represents a new source of chronological information for late Quaternary studies.

Potential for C 14 dating of biogenic carbonate in Hackberry (Celtis) endocarps

Potential for C 14 dating of biogenic carbonate in Hackberry (Celtis) endocarps
Action biogène ; Archéologie ; Carbonate ; Datation ; Datation C 14 ; Etats-Unis ; Méthodologie ; Nebraska ; Quaternaire ; Utah
Archaeology ; Biogenic process ; C 14 dating ; Carbonate ; Dating ; Methodology ; Nebraska ; Quaternary ; United States of America ; Utah
This paper reports on C 14 systematics of modern hackberry endocarp carbonate and examine its potential as a C 14 dating substrate. C 14 dates of fossil endocarp carbonates compared favorably with dates obtained by other means at archaeological
and geological sites ranging in age from the late Pleistocene through the early Holocene. They therefore suggest that hackberry endocarp is a suitable substrate for C 14 dating provided that its morphological and mineralogical integrity is preserved.

Etudes au carbone radioactif comme base d'évaluation des flux de carbone dans le système sol-atmosphère

Etudes au carbone radioactif comme base d'évaluation des flux de carbone dans le système sol-atmosphère
Carbone ; Cycle du carbone ; Datation C 14 ; Flux ; Humus ; Interaction sol-atmosphère ; Paléosol ; Russie d'Europe ; Sol
C 14 dating ; Carbon ; Carbon cycle ; European part of Russia ; Flow ; Humus ; Palaeosol ; Soil
Des modèles de renouvellement du carbone des sols d'après des données de carbone 14 sont utilisés pour évaluer les flux de carbone du système sol-atmosphère aux niveaux local et régional. Etablissement des vitesses d'échange du carbone et de leurs

Datations au carbone 14

Datations au carbone 14

Problèmes liés à la datation des sols fossiles par le carbone 14

Problèmes liés à la datation des sols fossiles par le carbone 14
Radiocarbon dating of fossil soils sometimes sets a difficult problem of interpretation because of the complexity of dynamic processes of organic carbon in the soil. Yet, fiability of dates mainly depends on the validity of the samples.

Phytolith and carbon isotope evidence for late Quaternary vegetation and climate change in the Southern Black Hills, South Dakota

Phytolith and carbon isotope evidence for late Quaternary vegetation and climate change in the Southern Black Hills, South Dakota
Analyse isotopique ; Carbone ; Datation C 14 ; Etats-Unis ; Formation herbacée ; Holocène ; Paléobiogéographie ; Phytolithe ; Quaternaire ; South Dakota ; Variation climatique ; Végétation
C 14 dating ; Carbon ; Climatic variation ; Grassland ; Holocene ; Isotope analysis ; Palaeobiogeography ; Quaternary ; South Dakota ; United States of America ; Vegetation
Analyses of phytoliths and carbon isotopes document the rate and nature change in late Quaternary grasslands in the Red Valley of the southern Black Hills. This paper will evaluate the temporal sensitivity and spatial limits of the methods.

Continuous lake-sediment records of glaciation in the Sierra Nevada between 52,600 and 12,500 C 14 yr B.P.

Continuous lake-sediment records of glaciation in the Sierra Nevada between 52,600 and 12,500 C 14 yr B.P.
California ; Carbonate ; Datation C 14 ; Etats-Unis ; Glaciation ; Géochimie ; Géochronologie ; Paléo-environnement ; Pléistocène ; Quaternaire ; Sierra Nevada ; Susceptibilité magnétique ; Sédiment lacustre
C 14 dating ; California ; Carbonate ; Geochemistry ; Geochronology ; Glaciation ; Lacustrine sediment ; Magnetic susceptibility ; Palaeo-environment ; Pleistocene ; Quaternary ; Sierra Nevada ; United States of America
for the period 52,600 to 12,500 C 14 yr B.P. A study of the chemistry of the carbonate-free clay-size fraction reported in this paper supports the previous use of total organic carbon and magnetic susceptibility as robust indicators of stade/interstade

Factors affecting 14C ages of lacustrine carbonates : timing and duration of the Last Highstand Lake in the Lahontan Basin

Factors affecting 14C ages of lacustrine carbonates : timing and duration of the Last Highstand Lake in the Lahontan Basin
California ; Carbonate ; Datation C 14 ; Etats-Unis ; Géochimie ; Lac ; Nevada ; Niveau lacustre ; Paléogéographie
C14 dating ; California ; Carbonate ; Geochemistry ; Lake ; Lake level ; Nevada ; Palaeogeography ; United States
The purposes of this paper are to determine when corrections for low initial 14C/c ratios in lake water should be made and which Lahontan carbonates listed in published carbonate 14C data bases (e.g., Benson, 1978, 1981; Benson et al., 1991) have
remained closed systems with respect to the isotopes of carbon. Based on these determinations, the most reliable of the carbonate 14C ages are used to calculate carbonate accumulation rates. The accumulation rates then are applied to the measured thickness
of highstand carbonates and used to estimate the timing and duration of the last Lake Lahontan highstand.

Prirodnyj radiouglerod i osobennosti gumusa sovremennyh i pogrebennyh černozemov

Carbone radioactif naturel et particularités de l'humus des tchernozems actuels et fossiles
Carbone ; Chernozem ; Faune fossile ; Holocène ; Humus ; Matière organique ; Radioactivité ; Russie d'Europe ; Sol ; Stratigraphie ; Ukraine
Carbon ; Chernozem ; European part of Russia ; Fossil fauna ; Holocene ; Humus ; Organic materials ; Radioactivity ; Soil ; Stratigraphy ; Ukraine
Carbone radioactif dans les sols et indices de l'âge du radiocarbone, indices de la concentration en carbone 14 à partir de la masse du sol et de la matière organique, du rapport géochimique carbone 14/carbone 12.

Use of bomb-C 14 to investigate the growth and carbon turnover rates of a crustose lichen

Use of bomb-C 14 to investigate the growth and carbon turnover rates of a crustose lichen
Cycle du carbone ; Datation ; Datation C 14 ; Etude comparée ; Lichen ; Lichénométrie ; Méthodologie ; Quaternaire ; Royaume-Uni ; Scotland ; Vitesse de croissance
C 14 dating ; Carbon cycle ; Comparative study ; Dating ; Growth rate ; Lichen ; Lichenometry ; Methodology ; Quaternary ; Scotland ; United Kingdom
Ciclo del carbono ; Cuaternario ; Datación ; DataciónCarbono 14 ; Estudio comparativo ; Liquen ; Liquenometria ; Metodología
The AA. investigated the use of bomb-C 14 analysis to determine the growth rate of a different crustose species (Pertusaria pseudocorallina) common to Northern Europe, recovered near Lochearnhead, central Scotland. C 14-based growth rates were
considerably higher than growth rates of morphologically similar species based on direct measurements made at locations nearby and elsewhere in the UK. This result suggests that a degree of carbon turnover probably occurs in Pertusaria pseudocorallina
, and that bomb-C 14 analysis alone cannot be used to determine lichen age or absolute growth rates in this lichen species.

Holocene monsoon changes inferred from lake sediment pollen and carbonate records, northeastern Cambodia

Holocene monsoon changes inferred from lake sediment pollen and carbonate records, northeastern Cambodia
Cambodge ; Carbonate ; Datation C 14 ; Diagramme pollinique ; Dynamique de la végétation ; Holocène ; Mousson ; Palynologie ; Paléo-environnement ; Quaternaire ; Sédiment lacustre
C 14 dating ; Cambodia ; Carbonate ; Holocene ; Lacustrine sediment ; Monsoon ; Palaeo-environment ; Palynology ; Pollen diagram ; Quaternary ; Vegetation dynamics
Major Holocene monsoon changes in continental southeast Asia are reconstructed from analysis of C 14 dated changes in pollen and organic/inorganic carbon in sediment cores taken from permanent, closed-basin, volcanic lakes in Ratanakiri Province

Holocene carbonate precipitates on Precambrian bedrock in the High Arctic : age and potential for palaeoclimatic information

Holocene carbonate precipitates on Precambrian bedrock in the High Arctic : age and potential for palaeoclimatic information
Arctique ; Canada ; Carbonate ; Datation C 14 ; Ellesmere ; Encroûtement ; Fluctuation du glacier ; Holocène ; Météorisation ; Northwest Territories ; Paléoclimatologie ; Variation climatique ; Zone froide
Arctic Region ; C 14 dating ; Canada ; Carbonate ; Climatic variation ; Cold area ; Duricrust ; Ellesmere ; Glacier fluctuation ; Holocene ; Northwest Territories ; Palaeoclimatology ; Weathering
The aim of this article is : to describe the occurrence in a High Arctic area of some of these white carbonate deposits; to report the results of C 14 age determinations obtained so far from the vicinity of Cape Herschel and elsewhere to give

Carbon isotope composition of lake sediments in relation to lake productivity and radiocarbon dating

Carbon isotope composition of lake sediments in relation to lake productivity and radiocarbon dating
Canada ; Carbone ; Datation C 14 ; Géochimie ; Isotope ; Ontario ; Paléo-environnement ; Paléo-écologie ; Quaternaire ; Sédiment lacustre
C14 dating ; Canada ; Carbon ; Geochemistry ; Isotope ; Lacustrine sediment ; Ontario ; Paleo-ecology ; Paleo-environment ; Quaternary
can provide a reliable indicator of potential old carbon error.

Isotopical differentiation of groundwater of different hydrogeologic origin

Carbone 13 ; Carbone 14 ; Complexe aquifère ; Eau souterraine ; Grès ; Géographie physique ; Hydrogéologie ; Nappe aquifère ; Recharge naturelle ; Roche carbonatée ; Technique de recherche ; Teneur isotopique ; Tritium

Vegetation and climate in the lower reaches of the Yana River during the Holocene

Corrélation ; Datation C 14 ; Holocène ; Iakout-Sakha ; Palynologie ; Paléoclimatologie ; Reconstitution climatique ; Russie d'Asie ; Végétation
Asian part of Russia ; C 14 dating ; Climate reconstruction ; Correlation ; Holocene ; Palaeoclimatology ; Palynology ; Sakha ; Vegetation
Etudes antérieures du climat de la Iakoutie. Données palynologiques et de carbone 14. Corrélation entre ces deux techniques. Reconstitution du climat et de la végétation.

Geoarchaeological evidence for dredging in Tyre's ancient harbour, Levant

Chronostratigraphie ; Datation C 14 ; Dragage ; Géoarchéologie ; Liban ; Paléo-environnement ; Paléogéographie ; Port ; Sūr
C 14 dating ; Chronostratigraphy ; Geoarchaeology ; Harbour ; Lebanon ; Palaeo-environment ; Palaeogeography
Résultats chronostratigraphiques et de datation au carbone 14 de l'ancien port du nord de Tyr montrant des pratiques de dragage au cours des périodes romaine et byzantine.

Stable carbon isotope record of Holocene environmental change in the central Great Plains

Stable carbon isotope record of Holocene environmental change in the central Great Plains
Analyse isotopique ; Datation C 14 ; Etats-Unis ; Great Plains ; Holocène ; Loess ; Matière organique ; Nebraska ; Paléo-environnement ; Sécheresse ; Variation climatique
C 14 dating ; Climatic variation ; Drought ; Holocene ; Isotope analysis ; Loess ; Nebraska ; Organic materials ; Palaeo-environment ; United States of America
First the AA. review the background and methodology behind the use of stable isotopes of carbon in paleoenvironmental research; then, they consult the literature to describe their knowledge of ecosystem and climate change, including recurring

Cosmogenic C 14 in carbonate rocks

Cosmogenic C 14 in carbonate rocks
C 14 dating ; Carbonate rock ; Fault ; Geochemistry ; Geochronology ; Isotope dating ; Limestone ; Nevada ; United States of America ; Utah
Calcaire ; Datation C 14 ; Datation isotopique ; Etats-Unis ; Faille ; Géochimie ; Géochronologie ; Nevada ; Roche carbonatée ; Utah

Late Quaternary vegetation dynamics in the southern Amazon Basin inferred from carbon isotopes in soil organic matter

Late Quaternary vegetation dynamics in the southern Amazon Basin inferred from carbon isotopes in soil organic matter
Amazonie ; Amérique du Sud ; Analyse isotopique ; Carbone ; Datation C 14 ; Dynamique de la végétation ; Forêt ; Holocène ; Paléo-environnement ; Quaternaire ; Savane ; Variation climatique
Amazon Basin ; C 14 dating ; Carbon ; Climatic variation ; Forest ; Holocene ; Isotope analysis ; Palaeo-environment ; Quaternary ; Savanna ; South America ; Vegetation dynamics
Carbon isotopes of soil organic matter (SOM) were used to evaluate and establish the chronology of the vegetation dynamics of an ecosystem presently composed of savannas surrounded by forests. The study was carried out on a 200-km transect along

Radiocarbon geochemistry of modern and ancient Arctic Lake systems, Baffin Island, Canada

Baffin Land ; Bassin-versant ; Canada ; Datation C 14 ; Géochimie ; Géochronologie ; Matière organique ; Northwest Territories ; Sédiment lacustre ; Zone froide
Baffin Land ; C 14 dating ; Canada ; Cold area ; Geochemistry ; Geochronology ; Lacustrine sediment ; Northwest Territories ; Organic materials ; Watershed
The accuracy of Arctic lake chronologies has been assessed by measuring the C 14 activities of modern carbon sources and applying these isotopic mass balances to dating fossil lake materials. Radiocarbon measurements of components of the lacustrine
carbon pool imply that the 1000 C 14 yr age of the sediment-water interface results from deposition of C 14-depleted organic matter derived from the watershed.

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