نتایج جستجو برای: radiocarbon dating
تعداد نتایج: 18604 فیلتر نتایج به سال:
The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity w...
Radiocarbon dating was performed for the extracted organic fractions (cellulose-rich and humic acid fractions of plant fragment; fulvic acid, humic acid and humin fractions of humus substance) and shell from core sediments of the Erhai Lake, SW China. The 14C dating results reveal that there are considerable differences, but there apparently is a humic acid ≤ humin < fulvic acid fraction sequen...
Radiocarbon dating of mortars is a method for absolute historical mortared stone structures. Successful mortar studies have answered chronological questions, while other revealed that samples can complications and contaminants. These cause inconclusive results even with present state-of-the-art techniques. Previous research shows adequate proper sampling fundamental importance conclusive radioc...
This investigation uses a multidisciplinary approach including geomorphic surface mapping, soil stratigraphic analysis, radiocarbon dating and optically stimulated luminescence (OSL) dating to investigate the chronology of soil formation and aeolian activation periods recorded in ridge dune deposits as well as the spatial variability of aeolian processes during active aeolian episodes. This stu...
This paper illustrates how archaeomagnetic dating can be used for palaeochannel fills within floodplain sequences. The sites investigated are palaeochannels associated with the mediaeval braided/anastomosing channels of an unstable reach of the River Trent at Hemington, north-west Leicestershire. This reach has revealed abundant archaeological remains including fish weirs, anchor stones, a Norm...
The study of human evolution has been revolutionized by inferences from ancient DNA analyses. Key to these studies is the reliable estimation of the age of ancient specimens. High-resolution age estimates can often be obtained using radiocarbon dating, and, while precise and powerful, this method has some biases, making it of interest to directly use genetic data to infer a date for samples tha...
Two sites in the Orinoco Valley containing preceramic from excavated contexts are described. Radiocarbon dating and stylistic comparisons indicate that the northern tropical lowlands were inhabited at the onset of the Holocene, suggesting a time depth of 9000 years before the present for tropical forest-savanna adaptations in northern South America.
[1] The causes for discordant radiocarbon results on multiple species of planktonic foraminifera from highsedimentation-rate marine sediments are investigated. We have documented two causes for these anomalous results. One is the addition of secondary radiocarbon for which we have, to date, only one firm example. It involves an opal-rich sediment. The other is the incorporation of reworked mate...
The role that small particle accelerators play in the field of applications to Cultural Heritage (for material analysis and dating) is critically discussed also in comparison to other techniques, pointing out pros and cons. As to material analysis, some peculiarities of ion beam techniques may be now less unique than they were perhaps ten years ago, but these techniques can still reach unrivall...
A long held view about the occupation of southern proto-Jê pit house villages of the southern Brazilian highlands is that these sites represent cycles of long-term abandonment and reoccupation. However, this assumption is based on an insufficient number of radiocarbon dates for individual pit houses. To address this problem, we conducted a programme of comprehensive AMS radiocarbon dating and B...
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