Chemical Isotope Dilution for 14C Ams and the Potential for GC/AMS

Radiocarbon ◽  
1986 ◽  
Vol 28 (3) ◽  
pp. 1065-1067 ◽  
Author(s):  
Richard Gillespie
Keyword(s):  
Radiocarbon Dating ◽  
Minimum Sample Size ◽  
Dilution Ratio ◽  
Combustion Gas ◽  
Ams Radiocarbon Dating ◽  
Beta Counting ◽  
Careful Measurement ◽  
Environmental Work ◽  
Sample Dilution ◽  
Gas Pressures

The advent of accelerator-based mass spectrometry (AMS) radiocarbon dating has reduced the minimum sample size required to ca 1 mg from the 1 g of traditional beta counting techniques (cf Wölfli, Polach & Andersen, 1984). However, it is clear that even smaller samples will be necessary for some fields of endeavor, particularly environmental work where the absolute quantities are small, perhaps of the order of a few micrograms (Currie et al, 1985). This raises serious problems in the handling and measurement of such small amounts, so that dilution will sometimes be required. Normally, sample dilution is accomplished by adding “dead” CO2 to the combusted sample CO2, which requires very careful measurement of two gas pressures for the calculation of a dilution ratio. By forming a chemical derivative of a sample before combustion, gas pressure measurement is not necessary and an exact dilution ratio can be selected by judicous choice of the dilution reagent. This paper demonstrates that such a technique is possible for the AMS 14C dating of derivatized amino acids.

AMS Radiocarbon Dating of the Type Plainview and Firstview (Paleoindian) Assemblages: The Agony and the Ecstasy

1999 ◽  
Vol 64 (3) ◽  
pp. 444-454 ◽  
Author(s):  
Vance T. Holliday ◽  
Eileen Johnson ◽  
Thomas W. Stafford
Keyword(s):  
Amino Acids ◽  
Great Plains ◽  
Radiocarbon Dating ◽  
Southern Plains ◽  
Ams Radiocarbon Dating ◽  
Tight Cluster ◽  
Bison Antiquus

Plainview and Firstview are two of the principal post-Folsom Paleoindian artifact assemblages on the Great Plains, but good radiometric age control for these artifact styles is relatively poor, due in part to lack of reliable age control on the type collections. This study reports the results of AMS-radiocarbon dating of specific amino acids from Bison antiquus bone associated with the type Plainview and Firstview assemblages from the Plainview and Olsen-Chubbuck sites, respectively. Seven samples of bone and teeth from Plainview produced a surprisingly wide array of ages. As a result, the age of the bone bed and the type Plainview collection remain uncertain, but it is most likely ≥ 10,000 B.P. (but late or post-Folsom) given the dating and stratigraphic relationships at Plainview and other sites. Seven samples of bone from Olsen-Chubbuck yielded a tight cluster of ages averaging ca 9400 B.P., fitting well with other dated Firstview features on the Southern Plains. These results show that much better age control from more sites is needed in order to understand the Paleoindian record. AMS-radiocarbon dating of specific amino acids from bone has revolutionized such issues of chronology in archaeology, but like any other method, it can provide confusing results and must be used in conjunction with other chronometric data.

Factors affecting the reliability of the McMaster technique

1986 ◽  
Vol 60 (4) ◽  
pp. 260-262 ◽  
Author(s):  
Alison Dunn ◽  
Anne Keymer
Keyword(s):  
Salt Solution ◽  
Time Interval ◽  
Dilution Ratio ◽  
Laboratory Procedure ◽  
Heligmosomoides Polygyrus ◽  
Factors Affecting ◽  
Faecal Material ◽  
Mcmaster Technique ◽  
Sample Dilution ◽  
Normal Laboratory

ABSTRACTFactors detraction from the reliability of faecal egg counts based on the McMaster technique include variation in flotation time (interval between loading chamber and counting eggs) and sample dilution (ratio of faecal material to salt solution). We recommend standardization of both these variables as normal laboratory procedure, and propose optima of a 30 minute flotation time and a sample dilution of 15 ml salt solution/ g faeces for use of the McMaster technique in the estimation of the fecundity of Heligmosomoides polygyrus (Nematoda).

Absolute Dating of the Virje and Hlebine Sites

2021 ◽  
pp. 92-100
Author(s):  
Katarina Botić
Keyword(s):  
Environmental Change ◽  
Bayesian Model ◽  
Radiocarbon Dating ◽  
Iron Formation ◽  
Iron Production ◽  
Formation Processes ◽  
Residential Areas ◽  
Ams Radiocarbon Dating ◽  
Absolute Dating ◽  
Cool Conditions

In this chapter the results of AMS radiocarbon dating of 26 charcoal samples from four sites are discussed. The primary aim was to explore the scope of (dis)continuity of temporally and functionally interconnected types of sites (settlement and iron production workshop). A Bayesian model was created based on the acquired data from excavated sites with three sequences in the model determined. The results show great accordance with the archaeologically based data, with some exceptions that are most probably a result of modelling strategy used. Contemporaneity of all four sites is mostly attested with a possible and very short temporal hiatus around AD 600. Occupation of workshop and residential areas at that time or slightly after may have been linked to the globally attested environmental change during the Bond 1 event when dry and cool conditions prevailed and which could have had an impact on bog iron formation processes.

scholarly journals AMS Radiocarbon Dating of Bones at Arizona

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 231-238 ◽  
Author(s):  
Austin Long ◽  
A T Wilson ◽  
R D Ernst ◽  
B H Gore ◽  
P E Hare
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Preliminary Analysis ◽  
Radiocarbon Dating ◽  
Quantitative Information ◽  
Fossil Bone ◽  
Bone Material ◽  
Ams Radiocarbon Dating ◽  
Fossil Bones ◽  
Extraneous Material

Modern bone contains ca 25% protein material, most of which is collagen. Amino acids separated from collagen isolated from bone are suitable for 14C dating of fossil bone, but attempts to carry out this procedure on bones seriously depleted in protein can yield erroneous 14C dates. Amino-acid analysis of fossil bone gives quantitative information on the degree of preservation of its organic component. Also, the relative abundance of the amino-acid components reveal the degree to which the collagen-like pattern has been altered. Alteration may be caused by addition of extraneous material. A 1mg sample of bone material is sufficient for this preliminary analysis. We have developed a series of acceptance criteria for whether a particular specimen is likely to yield the correct 14C age. 14C dating of fossil bones not seriously depleted in protein is a straightforward procedure and yields reliable dates.

scholarly journals Chronostratigraphic Sequence of Santuario Della Madonna Cave (Calabria, Southern Italy): AMS Radiocarbon Data from a New Excavation Area

Radiocarbon ◽  
2010 ◽  
Vol 52 (2) ◽  
pp. 408-414 ◽  
Author(s):  
L Calcagnile ◽  
V Tinè ◽  
G Quarta ◽  
M D'Elia ◽  
G Fiorentino ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Bronze Age ◽  
Radiocarbon Dating ◽  
Southern Italy ◽  
Statistical Tools ◽  
Ams Radiocarbon Dating ◽  
Cultural Aspects ◽  
Radiocarbon Data ◽  
Middle Bronze Age ◽  
Excavation Area

The Santuario della Madonna Cave, located near Praia a Mare (Cosenza), along the northwestern coast of Calabria (southern Italy), has an impressive stratigraphy, with occupation phases spanning from the late Paleolithic to the advanced phases of the Middle Bronze Age. Recently, a new excavation area has been opened in the cave from which shortlived vegetal remains were sampled and submitted for accelerator mass spectrometry (AMS) radiocarbon dating. The aim of this study was to define an accurate chronology of the different cultural aspects and to explore the potentialities resulting from application of advanced statistical tools for 14C data analysis in such a context.

scholarly journals 14C Wiggle-Matching of the B-Tm Tephra, Baitoushan Volcano, China/North Korea

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 933-940 ◽  
Author(s):  
Shinya Yatsuzuka ◽  
Mitsuru Okuno ◽  
Toshio Nakamura ◽  
Katsuhiko Kimura ◽  
Yohei Setoma ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
North Korea ◽  
Radiocarbon Dating ◽  
Gas Emission ◽  
Volcanic Gas ◽  
Ams Radiocarbon Dating ◽  
Eruption Age ◽  
The Difference ◽  
Volcanic Gas Emission

We performed accelerator mass spectrometry (AMS) radiocarbon dating and wiggle-matching of 2 wood samples from charred trunks of trees (samples A and B) collected from an ignimbrite deposit on the northeastern slope of the Baitoushan Volcano on the border of China and North Korea. The obtained calendar years for the eruption are cal AD 945–960 for sample A and cal AD 859–884 and cal AD 935–963 for sample B in the 2-σ range. These results are unable to determine the precise eruption age. The reason for the difference in reported ages may be due to volcanic gas emission prior to the huge eruption.

scholarly journals Over 16,000 Years of Fire Frequency Determined from AMS Radiocarbon Dating of Soil Charcoal in an Alluvial Fan at Bear Flat, Northeastern British Columbia

Radiocarbon ◽  
2006 ◽  
Vol 48 (3) ◽  
pp. 435-450 ◽  
Author(s):  
A J Timothy Jull ◽  
Marten Geertsema
Keyword(s):  
British Columbia ◽  
Radiocarbon Dating ◽  
Large Scale ◽  
Fire Frequency ◽  
Alluvial Fan ◽  
Before Present ◽  
Ams Radiocarbon Dating ◽  
Soil Charcoal ◽  
Large Fires ◽  
Millennial Time Scale

We present results of radiocarbon dating of charcoal from paleosols and buried charcoal horizons in a unique sequence, which potentially records the last 36,000 yr, from a fan at Bear Flat, British Columbia (BC) (56°16'51’N, 121°13'39”W). Evidence for forest-fire charcoal is found over the last 13,500 ± 110 14C yr before present (BP) or 16,250 ± 700 cal BP. The study area is located east of the Rocky Mountains in an area that was ice-free at least 13,970 ± 170 14C yr BP (17,450–16,150 cal BP) ago. The latest evidence of fire is during the Medieval Warm Period (MWP). The charcoal ages show a periodicity in large fires on a millennial scale through the Holocene—an average of 4 fires per thousand years. Higher fire frequencies are observed between 2200 to 2800 cal BP, ∼5500 and ∼6000 cal BP, ∼7500 to 8200 cal BP, and 9000 to 10,000 cal BP. These intervals also appear to be times of above-average aggradation of the fan. We conclude that fire frequency is related to large-scale climatic events on a millennial time scale.

scholarly journals AMS Radiocarbon Dating of Tianma-Qucun Site in Shanxi, China

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 1109-1114 ◽  
Author(s):  
Zhiyu Guo ◽  
Kexin Liu ◽  
Xiangyang Lu ◽  
Hongji Ma ◽  
Kun Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Bayesian Analysis ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Lower Boundary ◽  
Historical Record ◽  
Shanxi Province ◽  
Ams Radiocarbon Dating ◽  
Western Zhou ◽  
Calibration Program

Tianma-Qucun is the biggest site of Western Zhou Dynasty discovered in Shanxi Province, China. It has been recognized as the early capital of Jin, a vassal state of Western Zhou. The territories were granted to the first Marquis of Jin with the title in the early days of Western Zhou. Bone sample series from the site were radiocarbon-dated by accelerator mass spectrometry (AMS) and calibrated with the Oxford calibration program OxCal 3.5. Bayesian analysis of the calibrated ages shows that the earliest residents of the Western Zhou came to Tianma-Qucun area in 1020–940 BC and the lower boundary of the Western Zhou is 796–754 BC, which corresponds well to the historical record 770 BC.

scholarly journals A Simple Method to Separate Pollen for AMS Radiocarbon Dating and its Application to Lacustrine and Marine Sediments

Radiocarbon ◽  
1999 ◽  
Vol 41 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Scott A Mensing ◽  
John R Southon
Keyword(s):  
Mass Spectrometry ◽  
Lake Sediments ◽  
Marine Sediments ◽  
Radiocarbon Dating ◽  
Minimal Cost ◽  
Simple Method ◽  
Ams Radiocarbon Dating ◽  
Sediment Reworking ◽  
Scientific Equipment ◽  
Ams Dating

We present a simple method for manually separating pollen concentrates for radiocarbon accelerator mass spectrometry (AMS) dating using a mouth pipetting system. The required equipment is readily available from scientific equipment supply houses at minimal cost. Pollen samples from lake sediments required about 4 h of hand picking, whereas samples from marine sediments required about 8 h labor. Pollen dates from marine sediments were much older than expected. We are attempting to resolve whether this is due to contamination of the pollen or the presence of significant quantities of old reworked pollen. Pollen dates from lake sediments associated with Mazama Ash were consistent with other published ages; however, replicate dates on pollen samples from above the ash were consistently older than the surrounding sediment. Our results suggest that caution must be used when interpreting pollen dates if the potential for sediment reworking is present.

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