scholarly journals Application of 14C AMS Dating to the Chronology of Holocene Glacier Fluctuations in the High Arctic, With Special Reference to Leffert Glacier, Ellesmere Island, Canada

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 570-578 ◽  
Author(s):  
Weston Blake
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
High Arctic ◽  
Ellesmere Island ◽  
Present Position ◽  
Outlet Glacier ◽  
Radiocarbon Age ◽  
Ams Dating ◽  
Climatic Cooling ◽  
Age Determinations

A series of radiocarbon age determinations obtained by Accelerator Mass Spectrometry (AMS) shows that the front of Leffert Glacier, a major outlet glacier from the Prince of Wales Icefield, Ellesmere Island, was 18+ km behind (west of) its present position for a period of at least 1500 radiocarbon years. A subsequent readvance occurred close to 2000 radiocarbon years ago, as a consequence of the climatic cooling that followed the warm Hypsithermal Interval. A number of other glaciers in the region appear to have behaved in similar fashion.

scholarly journals Marine Turtle Bones from an Archaeological Site in Polynesia Yield Reliable Age Determinations

Radiocarbon ◽  
1990 ◽  
Vol 32 (2) ◽  
pp. 143-147 ◽  
Author(s):  
T S Dye
Keyword(s):  
Mass Spectrometry ◽  
Sample Size ◽  
Accelerator Mass Spectrometry ◽  
South Pacific ◽  
Archaeological Site ◽  
Marine Turtle ◽  
Long Distance ◽  
Marine Turtles ◽  
Ams Dating ◽  
Age Determinations

Accelerator mass spectrometry dating of three 50g samples of marine turtle bone from the basal cultural stratum of the Tongoleleka archaeological site, Lifuka Island, Kingdom of Tonga, South Pacific yields results that agree with conventional 14C dates on marine shell. A method for calibrating these dates that takes into account the long distance migrations of marine turtles in the South Pacific is proposed. A sample size greater than 50g is recommended for routine AMS dating of marine turtle bone.

scholarly journals New 14C Dates for the Early Natufian of El-Wad Terrace, Mount Carmel, Israel

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 813-822 ◽  
Author(s):  
Mina Weinstein-Evron ◽  
Reuven Yeshurun ◽  
Daniel Kaufman ◽  
Eileen Eckmeier ◽  
Elisabetta Boaretto
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Southern Levant ◽  
Radiocarbon Age ◽  
Cultural Affiliation ◽  
The Core ◽  
Integral Role ◽  
First Results ◽  
Age Determinations ◽  
Good Agreement

The Natufian culture of the southern Levant played an integral role in the transition from simple huntergatherers to food-producing societies of the Neolithic, but the major Natufian hamlets are currently poorly dated. Moreover, none of these complex, continuously occupied base camps have delivered an adequate number of dates to enable an in-depth delineation of intra-Natufian developments. This paper presents the first results of our dating program at el-Wad terrace, Mount Carmel (Israel), one of the major Natufian hamlets of the “core area” of this culture. Thirteen accelerator mass spectrometry (AMS) radiocarbon age determinations were obtained from 46 bone (both ungulate and human) and charcoal samples, originating in Early Natufian living surfaces, dwellings, and burials. The obtained dates are largely in agreement with the cultural affiliation of the samples (13–15 kyr cal BP). Two series of dates from different locations show good agreement with the stratigraphy. The ages of the burials clearly point to their being younger than the living surfaces seemingly associated with them. Presently, no burials may be linked with the major architectural phase of Early Natufian el-Wad. Our ongoing dating program and the processing of additional samples from refined contexts will help shed important light on the initial phases of the Natufian culture, habitation duration, intensity, and continuity, as well as the relationships between site features and stratigraphy.

scholarly journals Society Islands (Central Eastern Polynesia) Chronology: 11 Radiocarbon Dates for the Late Prehistoric Expansion and Proto-Historic Periods in the ‘Opunohu Valley, Mo'Orea

Radiocarbon ◽  
2006 ◽  
Vol 48 (3) ◽  
pp. 409-419 ◽  
Author(s):  
Jennifer G Kahn
Keyword(s):  
Mass Spectrometry ◽  
Late Prehistoric ◽  
Radiocarbon Dates ◽  
Radiocarbon Age ◽  
Society Islands ◽  
European Contact ◽  
Multiple Structures ◽  
Ams Dating ◽  
Central Eastern ◽  
Age Determinations

The chronology of residential site construction and occupation in the upper reaches of the ‘Opunohu Valley, Mo'orea, Central Eastern Polynesia, has been debated over the last 15 yr. This paper reports a suite of 11 radiocarbon age determinations from excavations at 5 house sites and a simple temple structure (marae). Direct accelerator mass spectrometry (AMS) dating of wood charcoal identified to short-lived taxa confirms site construction and occupation during the mid-15th to 17th centuries, supporting that maximal population density was in the centuries immediately prior to European contact. The study demonstrates that targeted dating of multiple structures within residential complexes allows for multiple phases of site construction and use to be discriminated. These data are critical for adequately assessing site contemporaneity and the development, maintenance, and expansion of residential groups and their house clusters through time.

Misunderstandings Concerning the Significance of AMS Background 14C Measurements

Radiocarbon ◽  
2018 ◽  
Vol 60 (3) ◽  
pp. 727-749
Author(s):  
R E Taylor ◽  
John R Southon ◽  
Guaciara M Santos
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Time Scale ◽  
Point Of View ◽  
General Validity ◽  
General Audience ◽  
Background Levels ◽  
Age Determinations

ABSTRACTWe consider one misconception of those who currently reject the general validity of radiocarbon (14C) age determinations older than, at most, 10,000 BP. There is an allegation that the presence of 14C reported by accelerator mass spectrometry (AMS) laboratories in their measurements of 14C infinite age (>100,000 years) organics used to define background levels, support their point of view. This article has been written for a general audience, primarily for those who have questions about the validity of these arguments. However, they may not be familiar with the literature relevant to providing a clear response to the claims of these individuals. We conclude that, in our view, of all of the possible explanations for the reports of the presence of 14C in these background samples, the least probable explanation has been advanced by those rejecting the validity of the 14C time scale in excess of, at most, 10,000 BP.

scholarly journals Reliability of Bone Gelatin AMS Dating: Rattus Exulans and Marine Shell Radiocarbon Dates from Pauatahanui Midden Sites in Wellington, New Zealand

Radiocarbon ◽  
1999 ◽  
Vol 41 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Nancy Beavan Athfield ◽  
Bruce McFadgen ◽  
Rodger Sparks
Keyword(s):  
Mass Spectrometry ◽  
New Zealand ◽  
Beta Decay ◽  
Confidence Level ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dates ◽  
Austrovenus Stutchburyi ◽  
Ams Dating ◽  
Marine Shell

A suite of 6 bone gelatin accelerator mass spectrometry (AMS) radiocarbon dates for Rattus exulans Peale and associated beta decay 14C dates for Austrovenus stutchburyi shell are presented for 4 middens at Pauatahanui, Wellington, New Zealand. Mean calibrated age ranges of Rattus exulans (520–435 BP and 350–330 BP at 95% confidence level) and shell (465–375 BP at 95% confidence level) from the 4 midden sites overlap. The agreement between Rattus exulans bone gelatin dates and associated shell provides an inter-sample comparison of 14C dating using both gas counting (beta decay) and AMS dating techniques. We examine the adequacy of the standard gelatinization treatment for bone samples, which has been employed consistently at the laboratory since 1995.

scholarly journals A Protocol for Radiocarbon Dating Tropical Subfossil Cave Guano

Radiocarbon ◽  
2009 ◽  
Vol 51 (3) ◽  
pp. 977-986 ◽  
Author(s):  
Christopher M Wurster ◽  
Michael I Bird ◽  
Ian Bull ◽  
Charlotte Bryant ◽  
Philippa Ascough
Keyword(s):  
Mass Spectrometry ◽  
Southeast Asia ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Saturated Hydrocarbon ◽  
Lipid Fraction ◽  
Bulk Sample ◽  
Radiocarbon Dates ◽  
Organic Fractions ◽  
Age Determinations

We present accelerator mass spectrometry (AMS) radiocarbon dates on several organic fractions isolated from tropical guano deposits recovered from insular Southeast Asia. Differences were observed between 14C measurements made on bulk guano as well as bulk lipids, the saturated hydrocarbon fraction, solvent-extracted guano, and insect cuticles extracted from the same bulk sample. We infer that 14C dates from the bulk lipid fraction and saturated hydrocarbon fractions can be variably contaminated by exogenous carbon. In contrast, 14C measurements on solvent-extracted guano and isolated insect cuticles appear to yield the most robust age determinations.

scholarly journals Examination of Background Contamination Levels for Gas Counting and AMS Target Preparation in Trondheim

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 312-317 ◽  
Author(s):  
Steinar Gulliksen ◽  
Mette S. Thomsen
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Target Preparation ◽  
Very Old ◽  
Ams Dating ◽  
Contamination Levels ◽  
Lower Background

The Radiological Dating Laboratory in Trondheim relatively often dates samples with ages >30 ka BP. Contaminated background materials are known to affect the accuracy of very old dates. We have found, by measurements of different materials, that such contamination is small when using our conventional gas proportional counting (GPC) system. We have also studied contamination levels of our target preparation for 14C accelerator mass spectrometry (AMS) dating in Uppsala. A significant lower background is obtained for Icelandic double spar than for marbles, probably due to a crystal structure of the double spar that is more insensitive to contaminating processes. The background for combusted samples is at the same level as for samples of double spar, indicating that additional 14C contamination due to combustion is negligible. Dates obtained on interstadial samples (T >30 ka bp) by both GPC and AMS agree well.

scholarly journals Determination of the Radiocarbon Age of Parchment of the Vinland Map

Radiocarbon ◽  
2002 ◽  
Vol 44 (1) ◽  
pp. 45-52 ◽  
Author(s):  
D J Donahue ◽  
J S Olin ◽  
G Harbottle
Keyword(s):  
Mass Spectrometry ◽  
Atlantic Ocean ◽  
Confidence Level ◽  
Accelerator Mass Spectrometry ◽  
Yale University ◽  
Rare Book ◽  
Radiocarbon Age ◽  
The One ◽  
Age Range

The Vinland Map, drawn on a 27.8 × 41.0 cm parchment bifolium, is housed in the Beinecke Rare Book and Manuscript Library at Yale University. In the northwest Atlantic Ocean, it shows “the Island of Vinland, discovered by Bjarni and Leif in company.” Skelton, Marston, and Painter (Skelton et al. 1965, 1995) firmly argued the map's authenticity, associating it with the Council of Basle (AD 1431–1449), that is, half a century before Columbus's voyage. Nevertheless, vigorous scholarly questioning of the map's authenticity has persisted (Washburn 1966; McCrone 1974; Olin and Towe 1976; Cahill et al. 1987; McCrone 1988; Towe 1990). We have determined the precise radiocarbon age of the map's parchment by accelerator mass spectrometry (AMS). The one-sigma calibrated calendrical date range is AD 1434 ± 11 years: the 95% confidence level age range is AD 1411–1468.

A 12 000 year radiocarbon date of deglaciation from the Continental Divide of northwestern Montana

1995 ◽  
Vol 32 (9) ◽  
pp. 1303-1307 ◽  
Author(s):  
Paul E. Carrara
Keyword(s):  
Mass Spectrometry ◽  
Previous Estimate ◽  
Outlet Glacier ◽  
Radiocarbon Age ◽  
Continental Divide ◽  
Northwestern Montana ◽  
Mountain Front ◽  
Ice Field ◽  
Late Wisconsinan ◽  
Wood Fragment

During the Pinedale (Late Wisconsinan) glaciation, an outlet glacier from a mountain ice field flowed eastward across the Continental Divide through Marias Pass in northwestern Montana. This outlet glacier was the major source of the Two Medicine glacier, a large piedmont glacier that extended from the mountain front east about 55 km onto the plains. An accelerator mass spectrometry radiocarbon age of 12 194 ± 145 BP (AA-9530) was obtained from a wood fragment, underlying a Glacier Peak tephra and a Mount Saint Helens set J tephra in a section of lake sediments, near Marias Pass. This radiocarbon age provides a minimum date of deglaciation for the Marias Pass area that is about 800 years older than a previous estimate. Furthermore, the radiocarbon age indicates that the Two Medicine glacier was no longer being supplied by its major source and if it still existed was only as a dying, stagnant ice mass.

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