scholarly journals Age Discrepancies with the Radiocarbon Dating of Sagebrush (Artemisia Tridentata Nutt.)

Radiocarbon ◽  
2008 ◽  
Vol 50 (3) ◽  
pp. 347-357 ◽  
Author(s):  
Phil R Geib
Keyword(s):  
Radiocarbon Dating ◽  
Artemisia Tridentata ◽  
Ground Surface ◽  
Wood Charcoal ◽  
Western United States ◽  
Archaeological Sites ◽  
Fuel Wood ◽  
Tree Wood ◽  
Plant Remains ◽  
Age Discrepancy

When ancient hearths at open archaeological sites do not yield carbonized annual plant remains or other high-quality samples, wood charcoal is commonly used for radiocarbon dating. Sagebrush (Artemisia tridentata Nutt.), a shrub frequently used for fuel across much of the western United States, seems a potentially better candidate for 14C dating than tree wood since the possibility for significant age discrepancy might be less. A comparison of multiple assays from single features reveals that sagebrush can overestimate age more than even tree wood charcoal. A plausible cause of this appears to be persistence of the shrub on the ground surface for an extended interval after death, such that use as fuel almost invariably occurs hundreds of years after fixation of carbon. The potential for age discrepancy may decrease as population density increases because the demand for fuel wood would have resulted in a more rapid turnover of the fuel biomass. This is not true for Archaic period foragers of western North America when population levels were likely quite low and residential mobility quite high.

scholarly journals Benefits and weaknesses of radiocarbon dating of plant material as reflected by Neolithic archaeological sites from Poland, Slovakia and Hungary

2017 ◽  
Vol 44 (1) ◽  
pp. 188-201 ◽  
Author(s):  
Marek Nowak ◽  
Magdalena Moskal-Del Hoyo ◽  
Aldona Mueller-Bieniek ◽  
Maria Lityńska-Zając ◽  
Krzysztof Kotynia
Keyword(s):  
Plant Material ◽  
Radiocarbon Dating ◽  
Production Systems ◽  
Archaeological Sites ◽  
Plant Materials ◽  
Hulled Wheats ◽  
Neolithic Age ◽  
Plant Remains ◽  
History Of ◽  
Cultivated Species

Abstract Radiocarbon dating of the plant material is important for chronology of archaeological sites. Therefore, a selection of suitable plant samples is an important task. The contribution emphasizes the necessity of taxonomical identification prior to radiocarbon dating as a crucial element of such selection. The benefits and weaknesses of dating of taxonomically undetermined and identified samples will be analysed based on several case studies referring to Neolithic sites from Hungary, Slovakia and Poland. These examples better illustrate the significance of the taxonomical identification since plant materials of the Neolithic age include only a limited number of cultivated species (e.g. hulled wheats) and typically do not contain remains of late arrived plants (e.g. Carpinus betulus and Fagus sylvatica). For more accurate dating results cereal grains, fruits and seeds, which reflect a single vegetative season, are preferred. Among charred wood, fragments of twigs, branches and external rings should mainly be taken into account, while those of trunks belonging to long-lived trees should be avoided. Besides the absolute chronology of archaeological features and artefacts, radiocarbon dating of identified plant remains might significantly contribute to the history of local vegetation and food production systems.

scholarly journals A New Radiocarbon Pretreatment Method for Molluscan Shell Using Density Fractionation of Carbonates in Bromoform

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1301-1311 ◽  
Author(s):  
Christopher M Russo ◽  
Jennifer A Tripp ◽  
Katerina Douka ◽  
Thomas F G Higham
Keyword(s):  
Radiocarbon Dating ◽  
Separation Technique ◽  
Archaeological Sites ◽  
Density Fractionation ◽  
Pretreatment Method ◽  
Density Separation ◽  
Molluscan Shell ◽  
Archaeological Artifacts ◽  
Organic Remains

Coastal archaeological sites that lack organic remains for radiocarbon dating are often abundant sources of molluscan shells. As a substitute for materials such as bone and charcoal, shells can be analyzed with 14C dating to determine a site's age. Despite their being convenient, non-mobile archaeological artifacts, molluscan shells are plagued by several issues, including carbonate remodeling, in which aragonite in shells is converted to calcite as predicted by thermodynamics. We present here a carbonate density separation technique that addresses the issue of carbonate remodeling. Using a density fractionation with bromoform, aragonite concentrations are enriched in shells that have undergone significant remodeling. The technique has been applied to archaeological shells and has returned dates that are younger than those previously determined for the same shells.

scholarly journals Radiocarbon Dating of Calcined Bones: Where Does the Carbon Come from?

Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 601-611 ◽  
Author(s):  
A Zazzo ◽  
J-F Saliège ◽  
A Person ◽  
H Boucher
Keyword(s):  
Radiocarbon Dating ◽  
Tooth Enamel ◽  
Skeletal Remains ◽  
Archaeological Sites ◽  
Carbonate Content ◽  
The Past ◽  
Mineral Fraction ◽  
Different Temperatures ◽  
C Value ◽  
Paleodietary Reconstruction

Over the past decade, radiocarbon dating of the carbonate contained in the mineral fraction of calcined bones has emerged as a viable alternative to dating skeletal remains in situations where collagen is no longer present. However, anomalously low δ13C values have been reported for calcined bones, suggesting that the mineral fraction of bone is altered. Therefore, exchange with other sources of carbon during heating cannot be excluded. Here, we report new results from analyses on cremated bones found in archaeological sites in Africa and the Near East, as well as the results of several experiments aiming at improving our understanding of the fate of mineral and organic carbon of bone during heating. Heating of modern bone was carried out at different temperatures, for different durations, and under natural and controlled conditions, and the evolution of several parameters (weight, color, %C, %N, δ13C value, carbonate content, crystallinity indexes measured by XRD and FTIR) was monitored. Results from archaeological sites confirm that calcined bones are unreliable for paleoenvironmental and paleodietary reconstruction using stable isotopes. Experimental results suggest that the carbon remaining in bone after cremation likely comes from the original inorganic pool, highly fractionated due to rapid recrystallization. Therefore, its reliability for 14C dating should be seen as close to that of tooth enamel, due to crystallographic properties of calcined bones.

scholarly journals Dating the Irrigation System of the Samarkand Oasis: A Geoarchaeological Study

Radiocarbon ◽  
2012 ◽  
Vol 54 (1) ◽  
pp. 91-105 ◽  
Author(s):  
Luca C Malatesta ◽  
Sébastien Castelltort ◽  
Simone Mantellini ◽  
Vincenzo Picotti ◽  
Irka Hajdas ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Radiocarbon Dating ◽  
Overland Flow ◽  
Irrigation System ◽  
Archaeological Sites ◽  
New Approach ◽  
Sedimentary Deposits ◽  
New Evidence ◽  
Southern Flank

The oasis of Samarkand in the Middle Zeravshan Valley (modern Uzbekistan) was a major political and economic center in ancient western Central Asia. The chronology of its irrigation system was, until now, only constrained by the quality and quantity of archaeological findings and several different hypotheses have been proposed for it. We use a new approach combining archaeological surveying, radiocarbon dating, sedimentary analysis, and the numerical modeling of a flood event to offer new evidence for, and quantitative dating of, the development of irrigation system on the southern flank of the Middle Zeravshan Valley. We analyzed 13 bones and charcoals from 3 archaeological sites and obtained new 14C ages from Afrasiab (ancient Samarkand), a dwelling damaged by flooding in the 2nd century AD (site code: SAM-174) and the fortress of Kafir Kala. We established the origin of sedimentary deposits at the sites to infer the presence of the 2 most important canals of the southern flank: the Dargom and the Yanghiaryk. Finally, we show with a numerical model of overland flow that a natural flood was unlikely to have produced the damage observed at SAM-174. The combined results of the study indicate that the canals south of Samarkand existed, and were mainly developed, in the 2nd century AD and were not connected to the main feeding canal of Afrasiab at that time.

scholarly journals Suitability of Ostrich Eggshell for Radiocarbon Dating

Radiocarbon ◽  
2001 ◽  
Vol 43 (1) ◽  
pp. 133-137 ◽  
Author(s):  
John C Vogel ◽  
Ebbie Visser ◽  
Annemarie Fuls
Keyword(s):  
Radiocarbon Dating ◽  
Archaeological Sites ◽  
Carbon Contamination ◽  
Suitable Material ◽  
Ostrich Eggshell

Ostrich eggshell from archaeological sites remains largely free of more recent carbon contamination and as such is suitable material for radiocarbon dating. The carbonate fraction of the shell does, however, display an initial deficit in 14C, which causes the ages to appear 180 ± 120 yr too old.

Collecting and Preserving Botanical Materials of Archaeological Interest

1944 ◽  
Vol 9 (3) ◽  
pp. 289-294 ◽  
Author(s):  
Elso S. Barghoorn
Keyword(s):  
Archaeological Site ◽  
Archaeological Sites ◽  
Careful Study ◽  
Significant Information ◽  
Chemical Changes ◽  
Plant Remains

In archaeological sites plant remains are frequently encountered either as artifacts or as natural deposits. A study of such remains commonly yields much valuable information, not only for the archaeologist but for other investigators as well. Thus, the former vegetation of a region and its possible bearing upon the previously existing climate are often revealed. Both the botanist and the paleontologist are interested in the preservation of plant remains and the structural and chemical changes which they have undergone since their deposition or submergence. In addition, of course, the careful study of woody artifacts frequently affords significant information regarding the Customs and practices of primitive peoples in working their materials. In order that the greatest value may be obtained from a study of botanical materials, however, it is essential that certain precautions and techniques be used in collecting and preserving them. Unfortunately, much botanical information available in an archaeological site is either discarded or overlooked in the process of digging and exposing the site.

scholarly journals Development of Radiocarbon Dating Method for Degraded Bone Samples from Korean Archaeological Sites

Radiocarbon ◽  
2011 ◽  
Vol 53 (1) ◽  
pp. 129-135 ◽  
Author(s):  
K J Kim ◽  
W Hong ◽  
J H Park ◽  
H J Woo ◽  
G Hodgins ◽  
...  
Keyword(s):  
Carbon Content ◽  
Depth Profile ◽  
Radiocarbon Dating ◽  
Archaeological Site ◽  
Archaeological Sites ◽  
The Past ◽  
Dating Method ◽  
Study Support ◽  
Ultrafiltration Process

The development of radiocarbon dating for degraded bone samples collected at Korean archaeological sites has been successful through the characterization of raw bone C/N ratios and application of an ultrafiltration method. It was found that the C/N ratios of raw bone samples are inversely proportional to the carbon content and residue amount after gelatinization. We have examined a few dozen Korean archaeological bone samples for this study. Well-preserved bone samples are found to be physically dense. The range of C/N ratios of Korean raw bone samples ranged from 3.4 to 74. We found that the C/N ratios of degraded raw bone samples can be used to determine whether 14C samples are acceptable for normal pretreatment processing and eventual dating. The results of this study support that even if the C/N ratio of a degraded raw bone sample is 11, extraction of collagen for bone dating is feasible by a carefully designed ultrafiltration process. Our preliminary 14C dating results of a depth profile of Gunang-gul Cave, an archaeological site in Danyang, Korea, indicate that this site has been either geologically or anthropologically disturbed in the past, with 14C ages ranging from 28,910 ± 200 to 48,090 ± 1050 yr BP. The C/N ratios of the collagen samples of Gunang-gul were determined to be 3.2–3.6. Our study establishes a new guide for the pretreatment of degraded bone samples such as those collected in Korea for 14C dating.

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