scholarly journals Geological Survey of Canada Radiocarbon Dates II

Radiocarbon ◽  
1963 ◽  
Vol 5 ◽  
pp. 39-55 ◽  
Author(s):  
W. Dyck ◽  
J. G. Fyles
Keyword(s):  
Sample Preparation ◽  
Oxalic Acid ◽  
Geological Survey ◽  
List Type ◽  
Type Number ◽  
Detectable Change ◽  
Concentrated Solutions ◽  
Radiocarbon Dates ◽  
Zero Reference ◽  
Age Determinations

The accompanying date list includes age determinations completed during the period December 1, 1961 to November 1, 1962. All measurements were made with the 2 L counter described in our first date list (GSC I). Sample preparation, counting procedures, and calculation of dates were as described in GSC I except as outlined below: a.Base and acid treatments were carried out with 1N HCl and 2% NaOH instead of 2N HCl and 4% NaOH, because the less-concentrated solutions were still strong enough to accomplish the desired purification.b.The Mg(C104)2 drying columns were removed from the purification train in order to test their effect, if any, on the purity of the gas. Since there was no detectable change in the purity of the gas these columns were left out of the purification line.c.Ages were calculated using 0.950 of the activity of the N.B.S. oxalic-acid standard as the reference activity and a.d. 1950 as the zero reference year, in line with the recommendations of the editors of Radiocarbon.

scholarly journals University of Granada Radiocarbon Dates III

Radiocarbon ◽  
1986 ◽  
Vol 28 (3) ◽  
pp. 1200-1205 ◽  
Author(s):  
Cecilio Gonzalez-Gomez ◽  
Purificacion Sanchez-Sanchez ◽  
Elena Villafranca-Sanchez
Keyword(s):  
Sample Preparation ◽  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Standard Sample ◽  
Research Project ◽  
Radiocarbon Dates ◽  
Preparation Techniques ◽  
Age Determinations ◽  
Modern Standard

The following list includes some measurements made from December 1982 to May 1985 in the Radiocarbon Dating Laboratory, Faculty of Science, University of Granada, of samples from Spain, Portugal, and the Sudan. Sample preparation techniques and benzene synthesis remain as described previously (R, 1982, v 24, p 217–221) and equipment and measurement of samples was also reported previously (R, 1985, v 27, p 610–615). Radiocarbon ages are calculated using the 14C half-life of 5570 years and 0.95 activity of NBS oxalic acid is used as modern standard. Sample descriptions are based on information provided by submitters. Age determinations were made with the help of Research Project 0925/81, CAICYT, Spain.

scholarly journals Illinois State Geological Survey Radiocarbon Dates III

Radiocarbon ◽  
1972 ◽  
Vol 14 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Dennis D. Coleman
Keyword(s):  
Sample Preparation ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Geological Survey ◽  
Radiocarbon Dates

The following date list includes all samples processed from December 1969 through November 1970 at the Illinois State Geological Survey Radiocarbon Dating Laboratory. The benzene liquid scintillation technique was used, following the method of Noakes, Kim, and Stipp (1965), and Noakes, Kim, and Akers (1967). Detailed sample preparation procedures used in this laboratory have been reported by Kim and Ruch (1969), and Kim, Ruch, and Kempton (1969).

scholarly journals U. S. Geological Survey Radiocarbon Dates VI

Radiocarbon ◽  
1961 ◽  
Vol 3 ◽  
pp. 86-98 ◽  
Author(s):  
Meyer Rubin ◽  
Sarah M. Berthold
Keyword(s):  
Oxalic Acid ◽  
19Th Century ◽  
Half Life ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
Appreciable Difference ◽  
The 19Th Century ◽  
Modern Standard

Dates in this list have been determined at U. S. Geological Survey radiocarbon laboratory, Washington, since our 1960 date list (USGS V). Procedures for the preparation of acetylene gas used in the counting, and the method of counting, (two days in two separate counters) remain unchanged. However, the modern standard used is no longer wood grown in the 19th century, but 95% of the activity of NBS oxalic-acid radiocarbon standard, as recommended at the 1959 Groningen Radiocarbon Conference. Measurement of the oxalic-acid standard at our laboratory indicates 6.2 ± 1% more C14 activity than our modern wood standard; so use of the new standard should make no appreciable difference when comparing samples computed by the old method. W. F. Libby's (1955) half-life average for C14, 5568 ± 30 years, was used for the decay equation.

scholarly journals Arizona Radiocarbon Dates VIII

Radiocarbon ◽  
1971 ◽  
Vol 13 (1) ◽  
pp. 1-18 ◽  
Author(s):  
C. Vance Haynes ◽  
Donald C. Grey ◽  
Austin Long
Keyword(s):  
Sample Preparation ◽  
Oxalic Acid ◽  
Half Life ◽  
Isotopic Fractionation ◽  
Radiocarbon Dates ◽  
Carbon Isotopic ◽  
Isotopic Analyses

The carbon isotopic analyses reported here covers the period since the last list (Haynes et al., 1967) until summer 1969. All results relating to secular C14 fluctuations in atmospheric CO2 are now published separately (Damon et al., 1970). Sample preparation and counting procedures remain essentially unchanged since completion of our conversion to CO2 in 1960. All δC13 values are reported relative to PDB and all C14 dates, unless otherwise noted, are based on the 5568 year half-life, but are not corrected for C13 content. 0.95 NBS oxalic acid activity is our routine standard periodically monitored for isotopic fractionation.

scholarly journals Illinois State Geological Survey Radiocarbon Dates IV

Radiocarbon ◽  
1973 ◽  
Vol 15 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Dennis D. Coleman
Keyword(s):  
Sample Preparation ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Sample Pretreatment ◽  
Geological Survey ◽  
Preparation Procedure ◽  
Synthesis System ◽  
Radiocarbon Dates ◽  
Sample Preparation Procedure ◽  
Scintillation Method

This date list includes all samples processed from December 1970 through November 1971 at the Illinois State Geological Survey Radiocarbon Dating Laboratory. The benzene liquid scintillation method of Noakes, Kim, and Stipp (1965), and Noakes, Kim, and Akers (1967) was used. A new benzene synthesis system has been completed, and several changes in the sample preparation procedure have been made since the last date list report (Coleman, 1972). A brief summary of the benzene synthesis and sample pretreatment techniques used to determine the dates reported here follows.

scholarly journals Geological Survey of Canada Radiocarbon Dates IV

Radiocarbon ◽  
1965 ◽  
Vol 7 ◽  
pp. 24-46 ◽  
Author(s):  
W. Dyck ◽  
J. G. Fyles ◽  
W. Blake
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Error Term ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
The Past ◽  
Average Variation

Most of the determinations reported here were obtained with the 2 L counter described in our first date list (GSC I). All age calculations are based on a C14 half-life of 5568 ± 30 yr and 0.95 of the activity of the NBS oxalic-acid standard, and the ages are quoted in years before 1950. The age errors include: counting errors of sample, background, and standard, the error in the half-life of C14, and an error term to account for the average variation of ±1.5% in the C14 concentration during the past 1100 yr. ‘Greater than’ ages are based on the 4 σ criterion (GSC II).

scholarly journals Dalhousie University Natural Radiocarbon Measurements II

Radiocarbon ◽  
1977 ◽  
Vol 19 (3) ◽  
pp. 392-399 ◽  
Author(s):  
J Gordon Ogden ◽  
W C Hart
Keyword(s):  
Sample Preparation ◽  
Oxalic Acid ◽  
Half Life ◽  
Background Activity ◽  
Small Samples ◽  
Age Determinations

The following list includes determinations completed since publication of our last date list (R, 1976, v 18, p 43-49). Sample preparation and counting configuration remains the same as for DAL-I. Age determinations are based on at least two counter fillings (except as noted for very small samples) for a total of 3000 minutes and are calculated from at least 5000 minutes modern and background counts updated weekly by alternating modern and background samples in the counters over weekends. Age calculations are based on the Libby half-life of 5568 y and includes 1 σ statistical uncertainties of sample, modern, and background activity. Reference age is ad 1950 and is determined from 95 oxalic acid activity or age-corrected 1850 wood.

scholarly journals Arizona Radiocarbon Dates VII

Radiocarbon ◽  
1967 ◽  
Vol 9 ◽  
pp. 1-14 ◽  
Author(s):  
C. Vance Haynes ◽  
Donald C. Grey ◽  
Paul E. Damon ◽  
Richmond Bennett
Keyword(s):  
List Type ◽  
Type Number ◽  
Radiocarbon Dates ◽  
Made In

The C14 measurements reported here were made in this laboratory between November 15, 1965 and June 15, 1966. Sample descriptions are classified as follows: I.Geochemical SamplesII.Geologic-Paleoclimatic SamplesIII.Early Man-Alluvial Stratigraphy SamplesIV.Archaeologic Samples

scholarly journals Arizona Radiocarbon Dates VI

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 1-21 ◽  
Author(s):  
C. Vance Haynes ◽  
Paul E. Damon ◽  
Donald C. Grey
Keyword(s):  
List Type ◽  
Type Number ◽  
Radiocarbon Dates ◽  
Made In

The C14 measurements reported here were made in this laboratory between November 1, 1963 and November 15, 1965. Sample descriptions are classified as follows: I.Geochemical SamplesII.Geologic-Paleoclimatic SamplesIII.Early Man-Alluvial Stratigraphy SamplesIV.Archaeologic Samples

scholarly journals Geological Survey of Canada Radiocarbon Dates I

Radiocarbon ◽  
1962 ◽  
Vol 4 ◽  
pp. 13-26 ◽  
Author(s):  
W. Dyck ◽  
J. G. Fyles
Keyword(s):  
Sample Preparation ◽  
Nuclear Research ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
Counting Procedure ◽  
Research Section ◽  
Cooperative Project

This paper reports the first ages determined in the C14Dating Laboratory of the Geological Survey of Canada. The C14dating program of the Geological Survey is a cooperative project; geologists of the Pleistocene Section assess and select samples for dating, and the Isotope and Nuclear Research Section, under Dr. R. K. Wanless, developed and operates the laboratory and calculates ages. The first part of this paper, devoted to sample preparation, counting procedure, and interlahoratory check dates was prepared by the first author, who built and operates the laboratory. The date list was compiled by the second author from descriptions of samples and interpretations of dates provided by various collectors. Most samples analyzed so far have originated within the Geological Survey.

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