scholarly journals US Geological Survey, Denver, Colorado Radiocarbon Dates III

Radiocarbon ◽  
1981 ◽  
Vol 23 (1) ◽  
pp. 24-32 ◽  
Author(s):  
I C Yang ◽  
R L McAvoy ◽  
R L Emerson
Keyword(s):  
Half Life ◽  
Geological Survey ◽  
Total Alkalinity ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
The Us ◽  
Age Limit

This list contains the results of measurements made during 1978 and 1979. Ages were computed on the radiocarbon half-life of 5568 ± 30 years. Statistical errors quoted herein are 1σ counting errors which include sample, background, and standard. The age limit reported is calculated on the basis of 3σ activity. The σ13C values in table 1 were measured by Krueger Enterprises, Inc, Geochron Laboratories Division1 and calculated based on Craig's Peedee Belemnite (PDB) limestone standard (Craig, 1957). The total alkalinity as bicarbonate values reported in table 1 was determined using techniques described by Brown, Skougstad, and Fishman (1970). Unless otherwise stated, all samples were collected and submitted by personnel of the US Geological Survey.

scholarly journals University of Michigan Radiocarbon Dates XV

Radiocarbon ◽  
1972 ◽  
Vol 14 (1) ◽  
pp. 195-222 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Standard Deviations

The following is a list of dates obtained since the compilation of List XIV, and the method is essentially the same. Two CO2–CS2 Geiger counter systems were used. Equipment and counting techniques have been described elsewhere (Crane, 1961). Dates and estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conference of 1962 and 1965, in that (a) dates are computed on the basis of the Libby half-life, 5570 yr, (b) A.D. 1950 is used as the zero of the age scale, and (c) the errors quoted are the standard deviations obtained from the number of counts only. In Michigan date lists up to and including VII, we quoted errors at least twice as great as the statistical errors of counting, to take account of other errors in the over-all process.

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 University of Michigan Radiocarbon Dates XI

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 256-285 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Standard Deviation ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Sources Of Error ◽  
The Many ◽  
Many Sources

The following is a list of dates obtained since the time of the compilation of List X in December 1964. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2Geiger counter systems are used. The equipment and counting techniques have been described elsewhere (Crane, 1961). The dates and estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conferences of 1962 and 1965, in that (a) dates are computed on the basis of the Libby half-life, 5570 yr, (b) A.D. 1950 is used as the zero of the age scale, and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In previous Michigan date lists up to and including VII we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many sources of error in the dating process, we suggest he double the figures that are given in this list.

scholarly journals University of Michigan Radiocarbon Dates VIII

Radiocarbon ◽  
1963 ◽  
Vol 5 ◽  
pp. 228-253 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Standard Deviation ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Counting Technique ◽  
Life Scale ◽  
The Many

The following is a list of dates obtained since the time of the compilation of List VII in December 1961. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2 Geiger counter systems are used. The equipment and counting technique have been described elsewhere (Crane, 1961a, 1961b). The dates and the estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conference of 1962, in that (a) dates are computed on the basis of a half life of 5568 years, (b) a.d. 1950 is used as the zero of the age scale and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In all previous Michigan date lists we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many other sources of error in the dating process, we suggest he double the figures that are given in this list. The procedures for converting the dates to the more recent half life scale and to a scale having its zero at any time other than 1950 need not be given here as they have been covered in this journal and elsewhere. Where there is no comment, it is because the submitter of the sample had none to make.

scholarly journals University of Michigan Radiocarbon Dates IX

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 1-24 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Standard Deviation ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Sources Of Error ◽  
Standard Deviations ◽  
The Many

The following is a list of dates obtained since the time of the compilation of List VIII in December 1962. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2 Geiger counter systems are used. The equipment and counting techniques have been described elsewhere (Crane, 1961a, 1961b). The dates and the estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conference of 1962, in that (a) dates are computed on the basis of the Libby half life, 5570 years, (b) a.d. 1950 is used as the zero of the age scale and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In previous Michigan date lists up to and including VII we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many other sources of error in the dating process, we suggest he double the figures that are given in this list. Where there is no comment, it is because the submitter of the sample had none to make.We wish to acknowledge the help of Patricia Dahlstrom in preparing chemical samples and Roscoe Wilmeth in preparing the descriptions. The descriptions and comments are essentially those of persons submitting the samples.

scholarly journals U. S. Geological Survey Radiocarbon Dates VII

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 37-76 ◽  
Author(s):  
Patricia C. Ives ◽  
Betsy Levin ◽  
Richard D. Robinson ◽  
Meyer Rubin
Keyword(s):  
Solid State ◽  
External Field ◽  
Half Life ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
Solid State Electronics ◽  
Counting Error ◽  
Atmospheric Variations ◽  
The One

This date list contains the results of measurements made during 1961, 1962 and 1963. The method of counting, utilizing acetylene gas, remains essentially unchanged, except for the addition of some solid state electronics. The method of computation, using the Libby half-life of 5568 ± 30 yr, is continued. The error listed is always larger than the one-sigma statistical counting error commonly used, and takes into account known uncertainty laboratory factors, and does not include external (field or atmospheric) variations.Unless otherwise stated, collectors of all samples are members of the U. S. Geological Survey.

scholarly journals University of Michigan Radiocarbon Dates XIV

Radiocarbon ◽  
1972 ◽  
Vol 14 (1) ◽  
pp. 155-194 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Standard Deviations

The following is a list of dates obtained since the compilation of List XIII (R., 1970, v. 12, p. 161–180). The method is essentially the same. Two CO2–CS2Geiger counter systems were used. Equipment and counting techniques have been described elsewhere (Crane, 1961). Dates and estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conferences of 1962 and 1965, in that (a) dates are computed on the basis of the Libby half-life, 5570 yr; (b) A.D. 1950 is used as the zero of the age scale; and (c) the errors quoted are the standard deviations obtained from the number of counts only. In Michigan date lists up to and including VII, we quoted errors at least twice as great as the statistical errors of counting in order to take into account other errors in the over-all process.

scholarly journals U. S. Geological Survey Radiocarbon Dates VIII

Radiocarbon ◽  
1965 ◽  
Vol 7 ◽  
pp. 372-398 ◽  
Author(s):  
Betsy Levin ◽  
Patricia C. Ives ◽  
Charles L. Oman ◽  
Meyer Rubin
Keyword(s):  
External Field ◽  
Half Life ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
Counting Error ◽  
Atmospheric Variations ◽  
The One

This list contains the results of measurements made during 1963 and 1964. Samples are counted in the form of acetylene gas, as previously, and ages computed using the Libby half-life of 5568 ± 30 yr. The error listed is always larger than the one-sigma statistical counting error commonly used, takes into account known uncertainty laboratory factors, but does not include external (field or atmospheric) variations.

scholarly journals University of Michigan Radiocarbon Dates XII

Radiocarbon ◽  
1968 ◽  
Vol 10 (1) ◽  
pp. 61-114 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Standard Deviation ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Sources Of Error ◽  
The Many ◽  
Many Sources

The following is a list of dates obtained since the compilation of List XI in December 1965. The method is essentially the same as described in that list. Two CO2-CS2Geiger counter systems were used. Equipment and counting techniques have been described elsewhere (Crane, 1961). Dates and estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conferences of 1962 and 1965, in that (a) dates are computed on the basis of the Libby half-life, 5570 yr, (b) A.D. 1950 is used as the zero of the age scale, and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In previous Michigan date lists up to and including VII, we have quoted errors at least twice as great as the statistical errors of counting, to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many sources of error in the dating process, we suggest doubling the figures that are given in this list.We wish to acknowledge the help of Patricia Dahlstrom in preparing chemical samples and David M. Griffin and Linda B. Halsey in preparing the descriptions.

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).

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