Testing the Accuracy of 14C Age Data from Pollen Concentrates in the Yangtze Delta, China

Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 181-187 ◽  
Author(s):  
Chunhai Li ◽  
Yongxiang Li ◽  
George S Burr
Keyword(s):  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Yangtze Delta ◽  
Plant Materials ◽  
Radiocarbon Dates ◽  
Ams Radiocarbon Dating ◽  
14C Age ◽  
Climate Events ◽  
Age Determinations

In order to test the accuracy of accelerator mass spectrometry (AMS) radiocarbon dating of pollen, 8 samples of pollen concentrates and 4 bulk organic samples were collected and analyzed from trench T1041 at the Tianluoshan site, Yuyao city, Zhejiang Province. This site was chosen because a reliable chronology had been previously established there based on radiocarbon dates of plant materials. The pollen concentrate samples were measured using AMS 14C and the 4 bulk organic samples were measured by liquid scintillation counting (LSC). The pollen concentrates and bulk organic samples yield ages that are a few hundred years to thousands of years older than those from plant materials, respectively. Contributions from reworked sediments can explain the older ages for the pollen concentrates and sediment organic dates. This study suggests that caution must be exercised when discussing millennial- or centennial-scale climate events based on chronologies that are controlled by age determinations of pollen concentrates.

scholarly journals Further Developments in On-Line Computing and Radiocarbon Dating At the British Museum

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 455-460 ◽  
Author(s):  
A D Hewson ◽  
J A Hall
Keyword(s):  
Research Laboratory ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Full Range ◽  
British Museum ◽  
Scintillation Counting ◽  
Hewlett Packard ◽  
Radiocarbon Dates ◽  
On Line ◽  
Reporting Procedures

In November 1973 the British Museum Research Laboratory acquired a Hewlett Packard 2100A mini-computer for the storage, calculation and retrieval of scientific measurements made on museum objects. A part of the computer's work is the calculation of radiocarbon dates based on the liquid scintillation counting of 14C activities. A system of programs and files has been developed and has been in daily use since August 1974 (Hall and Hewson, 1977).This paper describes changes and improvements to the system to make it more flexible so that it now provides the full range of facilities required by an active 14C laboratory. The reporting procedures in particular have been restructured in the light of experience. The paper will be of interest to all laboratories that have, or hope to have, access to similar mini- or micro-computers.

University of Granada Radiocarbon Dates I

Radiocarbon ◽  
1982 ◽  
Vol 24 (2) ◽  
pp. 217-221 ◽  
Author(s):  
Cecilio González-Gómez ◽  
Juan de D López-González ◽  
María Domingo-García
Keyword(s):  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Pure Oxygen ◽  
Radiocarbon Dates

The Radiocarbon Dating Laboratory of The Granada University was established to support the work of archaeologists and geologists. The method of dating is benzene synthesis and liquid scintillation counting developed by a number of investigators (Polach and Stipp, 1967; Tamers, 1969; Pietig and Scharpenseel, 1966) with sample combustion in pure oxygen (Switsur, 1974).

scholarly journals Yale University Geology and Geophysics Radiocarbon Dates I

Radiocarbon ◽  
1977 ◽  
Vol 19 (1) ◽  
pp. 138-141 ◽  
Author(s):  
Y Nozaki ◽  
K K Turekian
Keyword(s):  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Yale University ◽  
Radiocarbon Dates ◽  
Geochemical Parameters ◽  
Natural Tracer

A radiocarbon dating system has been established at the Department of Geology and Geophysics, Yale University. Liquid-scintillation counting of benzene described by Noakes et al (1965) and Polach and Stipp (1967) is used. The operation of the original Yale Radiocarbon Laboratory, based on counting CO2 gas, was suspended in 1969. The present facility is operated as part of the geochemical laboratories of the Department of Geology and Geophysics. The operation is small, geared to solving geochemical problems, through the use of radiocarbon as a dating tool and as a natural tracer in combination with other geochemical parameters. The facility will collaborate on significant archaeologic and geologic problems. However, it will not be a facility to which samples are submitted routinely. We believe that commercial facilities and other laboratories dedicated to such kinds of operation are better suited to handling such diversity and volume of samples.

scholarly journals University of Granada Radiocarbon Dates V

Radiocarbon ◽  
1991 ◽  
Vol 33 (3) ◽  
pp. 367-373 ◽  
Author(s):  
Cecilio Gonzalez-Gomez ◽  
Purificacion Sanchez-Sanchez
Keyword(s):  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Boiling Temperature ◽  
Liquid Scintillation Spectrometer ◽  
Radiocarbon Dates ◽  
Standard Acid ◽  
Basic Procedure ◽  
The University

This paper includes some determinations of archaeological, art and palaeobotanical samples from Spain and Portugal, obtained at the University of Granada Radiocarbon Dating Laboratory, mostly from 1986 to 1988. Pretreatment of charcoal and wood samples is a standard acid-basic procedure using 8% HC1 and 2% NaOH at boiling temperature. The collagen of bone samples is obtained by the Longin (1971) method.The method of dating is benzene synthesis and liquid scintillation counting as previously reported (González-Gómez, López-González & Domingo-García 1982; González-Gómez, Sánchez-Sánchez and Domingo-García 1985; González-Gómez, Sánchez-Sánchez and Villafranca-Sánchez 1986, 1987).14C activity was measured in a Packard Tri-Carb Mod 4640 liquid scintillation spectrometer, using 20 ml low 40K counting vials with 5 ml benzene and 10 ml PPO-toluene as scintillator with a background of ca. 9 cpm. Efficiency was approximately 70% using the part of spectrum above the end point of tritium.

scholarly journals University of Granada Radiocarbon Dates VIII

Radiocarbon ◽  
1997 ◽  
Vol 39 (3) ◽  
pp. 299-303
Author(s):  
Cecilio González-Gómez ◽  
Elena Villafranca-Sánchez
Keyword(s):  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Boiling Temperature ◽  
Radiocarbon Dates ◽  
Standard Acid ◽  
Basic Procedure ◽  
The University

This paper includes determinations of archaeological, geological and paleobotanical samples from Spain and Brazil, measured at the University of Granada Radiocarbon Dating Laboratory, mainly from 1991 to 1992. As previously reported (González-Gómez 1992), pretreatment of charcoal and wood samples is a standard acid-basic procedure using 8% HCl and 2% NaOH at boiling temperature. The collagen of bone samples was extracted by the Longin (1971) method. The method of dating is liquid scintillation counting of synthesized benzene.

scholarly journals University of Texas Radiocarbon Dates II

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 138-159 ◽  
Author(s):  
M. A. Tamers ◽  
F. J. Pearson ◽  
E. Mott Davis
Keyword(s):  
Chemical Synthesis ◽  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
The University

The Radiocarbon Dating Laboratory of the University of Texas was reorganized in late 1962. The dates reported in this list were obtained from February to November, 1963. The laboratory uses liquid scintillation counting with benzene solutions (Tamers, Stipp, and Collier, 1961; Noakeset al., 1963). The chemical synthesis has been modified and improved in several ways in order to permit one worker to produce a sample per day.

scholarly journals University of Granada Radiocarbon Dates VII

Radiocarbon ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 73-77
Author(s):  
Cecilio González-Gómez ◽  
Elena Villafranca-Sánchez
Keyword(s):  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Boiling Temperature ◽  
Radiocarbon Dates ◽  
Standard Acid ◽  
Basic Procedure ◽  
The University

This paper includes determinations of archaeological, geological and palaeobotanical samples from Spain and Portugal, measured at the University of Granada Radiocarbon Dating Laboratory, from 1990 to 1991. Pretreatment of charcoal and wood samples is a standard acid-basic procedure using 8% HCl and 2% NaOH at boiling temperature. The collagen of bone samples is obtained by the Longin (1971) method. The method of dating is benzene synthesis and liquid scintillation counting.

scholarly journals Rice University Radiocarbon Dates I

Radiocarbon ◽  
1973 ◽  
Vol 15 (1) ◽  
pp. 185-192
Author(s):  
Barry F. Beck
Keyword(s):  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Nitrate Solution ◽  
Silver Nitrate Solution ◽  
Scintillation Counting ◽  
Counting Method ◽  
Sodium Dichromate ◽  
Radiocarbon Dates ◽  
Potassium Permanganate Solution ◽  
Rice University

The radiocarbon dating laboratory at Rice University first became operative in the fall of 1970. A workable technique has been developed although operations are still in a state of flux. The benzene liquid scintillation counting method is used, the benzene being prepared as outlined by Noakes, Kim, and Akers (1967) with the following modifications. The CO2 is further purified prior to storage and measuring by passing it through 3 gas bubblers containing potassium permanganate solution, silver nitrate solution, and a sulfuric acid-sodium dichromate solution (S. Valastro, pers. commun., 1970). Since no C12 C13 analyses are available at present, to insure a complete reaction, both the CO2 generation and the C2H2 generation are continued for ½ hr after all visible signs of reaction have disappeared.

scholarly journals Simon Fraser University Radiocarbon Dates I

Radiocarbon ◽  
1982 ◽  
Vol 24 (3) ◽  
pp. 344-351 ◽  
Author(s):  
D E Nelson ◽  
K A Hobson
Keyword(s):  
Conversion Efficiency ◽  
Liquid Scintillation Counting ◽  
Chromatographic Analysis ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Reaction Vessel ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
Gas Chromatographic Analysis ◽  
Simon Fraser University

The SFU Archaeology Department has constructed a small radiocarbon dating facility to serve its own needs and, to the extent that time is available, the needs of other archaeologists and earth scientists. All dates reported here were processed by our laboratory from October 1979 to September 1980. The 14C measurements are made using conventional techniques for liquid scintillation counting of benzene. The samples are burned in a Phonon Mark IV combustion bomb and the resultant CO2 is purified and converted to Li2C2 using a reaction vessel based on the design of Polach, Gower, and Fraser (ms). Acetylene is formed by hydrolysis with distilled H2O which has been aged for a minimum of three months. The acetylene is trimerized to benzene with the Mobil Durabead I catalyst. The conversion efficiency of CO2 to C6H6 is typically 95%. Gas chromatographic analysis of typical samples of the synthesized benzene indicates 99.8% purity with toluene produced in trace amounts.

scholarly journals Hiroshima University Radiocarbon Dates II West and South Coasts of Sri Lanka

Radiocarbon ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Jinadasa Katupotha
Keyword(s):  
Sri Lanka ◽  
Oxalic Acid ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
The West ◽  
Laboratory Procedure ◽  
Radiocarbon Dates ◽  
Geologic Samples ◽  
Preparation Techniques

Geologic samples for 14C age measurements were collected from the west, southwest and south coasts of Sri Lanka during October and November 1986. Sample points were leveled based on the Colombo datum level. Results presented below were obtained by liquid scintillation counting of methanol for coral and shell samples. Ages were measured from December 1986 to May 1987, at the Department of Geography, Hiroshima University, Radiocarbon Dating Laboratory, using the laboratory procedure described by Fujiwara and Nakata (1984). Sample preparation techniques were similar to those mentioned in the first list (Katupotha, 1988). The results are expressed in radiocarbon years relative to ad 1950 based on the Libby half-life of 5568 ± 30 years, using the new oxalic acid standard (SRM 4900C) as ‘modern’ (Stuiver, 1983).

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