14c dating soil
To determine which fraction should be used for 14C dating of Andosols and to evaluate if the chronostratigraphy of SOM is suitable for paleoecological research, we measured 14C ages of both fractions and related calibrated ages to soil depth for Andosols in northern Ecuador.
Before this can be done, however, the sample must be treated to remove any contamination and any unwanted constituents.Therefore, radiocarbon dating of SOM is necessary, but unfortunately not straightforward.Dating of fractions of SOM obtained by alkali-acid extraction is promising, but which fraction (humic acid or humin) renders the most accurate 14C dates is still subject to debate.To correct this unstable condition, a neutron is converted into a proton, which keeps the nucleus the same size (i.e., the same atomic mass) but increases the number of protons (and therefore the atomic number) by one. For the first time, 12 ice cores drilled in the northern section of Greenland have been “stacked” and published.In the soils, calibrated ages increased significantly with increasing depth.
Age inversions and homogenization were not observed at the applied sampling distances.
Volcanic ash soils (Andosols) may offer great opportunities for paleoecological studies, as suggested by their characteristic accumulation of organic matter (OM).
However, understanding of the chronostratigraphy of soil organic matter (SOM) is required.
Facies variations in response to Holocene sea-level and climate change on Bora Bora, French Polynesia: Unravelling the role of synsedimentary siderite in a tropical marine, mixed carbonate-siliciclastic lagoon. (eds.) Du climat à l'homme: Dynamique holocène de l'environnement dans le jura et les alpes. Chambéry: Université des Savoie Hydrological variability in southeastern Patagonia and explosive volcanic activity in the southern Andean Cordillera during Oxygen Isotope Stage 3 and the Holocene inferred from lake sediments of Laguna Potrok Aike, Argentina. Wenzens 2005: Glacier advances east of the Southern Andes between the Last Glacial Maximum and 5,000 BP compared with lake terraces of the endorrheic Lago Cardiel (49 S, Patagonia, Argentina).
(ed.) Erosion und Denkmalschutz am Bodensee und Zürichsee : ein internationales Projekt im Rahmen des Interreg IV-Programms "Alpenrhein-Bodensee-Hochrhein" zur Entwicklung von Handlungsoptionen zum Schutz des Kulturgutes unter Wasser. Actes du colloque GDR JURALP organisé à Aix-en-Provence les 15 et 16 novembre 2007.
Humic acid (HA) was significantly older than humin, except for the mineral soil samples just beneath a forest floor (organic horizons), where the opposite was true.