High sensitivity radiocarbon dating in the 50,000 to 70,000 BP range without isotopic enrichment

A. Long, R. Kalin

Research output: Contribution to journalArticle

Abstract

Calculations show the possibility of detecting C-14 remaining after 10 or 11 decay half-lives in natural materials, such as wood, using commercially available liquid scintillation (LS) detectors. Assuming in-situ C-14 production has contributed insignificantly to the measured C-14, one can calculate finite ages approaching 70 ka. In practice, defensible finite age determinations involve careful considerations of several critical elements in the procedure. These critical elements are: 1) the integrity of the sample itself, in terms of younger contaminants and of in situ-produced C-14; 2) the availability of ''dead'' background material; 3) chemical blank in laboratory preparation of, in this case, benzene; and 4) stability of background and efficiency of the LS counting system. High-sensitivity C-14 dating reveals a low level of memory effect C-14 in benzene synthesized in the laboratory from anthracite or marble. This level of C-14 activity is equivalent to that found in 53 ka old wood, and thus, is not distinguishable from petrochemical benzene used in routine dating. If careful control of laboratory conditions can maintain this C-14 blank constant, reproducible dating beyond 53 ka would be possible. Although we have not completed a systematic analysis of the origins of memory effect, lithium reactors used in acetylene production and organic solvents in wood pretreatment are likely sources.
Original languageEnglish
Pages (from-to)351-359
Number of pages8
JournalRadiocarbon
Volume34
Issue number3
Publication statusPublished - 1992

Fingerprint

radiocarbon dating
Benzene
benzene
Wood
Decay (organic)
Data storage equipment
Acetylene
Marble
Scintillation counters
anthracite
liquid
Anthracite
Coal
Calcium Carbonate
Liquids
Scintillation
acetylene
age determination
lithium
marble

Keywords

  • radiocarbon dating
  • natural materials
  • wood
  • isotopic enrichment

Cite this

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title = "High sensitivity radiocarbon dating in the 50,000 to 70,000 BP range without isotopic enrichment",
abstract = "Calculations show the possibility of detecting C-14 remaining after 10 or 11 decay half-lives in natural materials, such as wood, using commercially available liquid scintillation (LS) detectors. Assuming in-situ C-14 production has contributed insignificantly to the measured C-14, one can calculate finite ages approaching 70 ka. In practice, defensible finite age determinations involve careful considerations of several critical elements in the procedure. These critical elements are: 1) the integrity of the sample itself, in terms of younger contaminants and of in situ-produced C-14; 2) the availability of ''dead'' background material; 3) chemical blank in laboratory preparation of, in this case, benzene; and 4) stability of background and efficiency of the LS counting system. High-sensitivity C-14 dating reveals a low level of memory effect C-14 in benzene synthesized in the laboratory from anthracite or marble. This level of C-14 activity is equivalent to that found in 53 ka old wood, and thus, is not distinguishable from petrochemical benzene used in routine dating. If careful control of laboratory conditions can maintain this C-14 blank constant, reproducible dating beyond 53 ka would be possible. Although we have not completed a systematic analysis of the origins of memory effect, lithium reactors used in acetylene production and organic solvents in wood pretreatment are likely sources.",
keywords = "radiocarbon dating, natural materials, wood, isotopic enrichment",
author = "A. Long and R. Kalin",
note = "14TH INTERNATIONAL RADIOCARBON CONF ( 14C14 ), TUCSON, AZ, MAY 20-24, 1991",
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journal = "Radiocarbon",
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High sensitivity radiocarbon dating in the 50,000 to 70,000 BP range without isotopic enrichment. / Long, A.; Kalin, R.

In: Radiocarbon, Vol. 34, No. 3, 1992, p. 351-359.

Research output: Contribution to journalArticle

TY - JOUR

T1 - High sensitivity radiocarbon dating in the 50,000 to 70,000 BP range without isotopic enrichment

AU - Long, A.

AU - Kalin, R.

N1 - 14TH INTERNATIONAL RADIOCARBON CONF ( 14C14 ), TUCSON, AZ, MAY 20-24, 1991

PY - 1992

Y1 - 1992

N2 - Calculations show the possibility of detecting C-14 remaining after 10 or 11 decay half-lives in natural materials, such as wood, using commercially available liquid scintillation (LS) detectors. Assuming in-situ C-14 production has contributed insignificantly to the measured C-14, one can calculate finite ages approaching 70 ka. In practice, defensible finite age determinations involve careful considerations of several critical elements in the procedure. These critical elements are: 1) the integrity of the sample itself, in terms of younger contaminants and of in situ-produced C-14; 2) the availability of ''dead'' background material; 3) chemical blank in laboratory preparation of, in this case, benzene; and 4) stability of background and efficiency of the LS counting system. High-sensitivity C-14 dating reveals a low level of memory effect C-14 in benzene synthesized in the laboratory from anthracite or marble. This level of C-14 activity is equivalent to that found in 53 ka old wood, and thus, is not distinguishable from petrochemical benzene used in routine dating. If careful control of laboratory conditions can maintain this C-14 blank constant, reproducible dating beyond 53 ka would be possible. Although we have not completed a systematic analysis of the origins of memory effect, lithium reactors used in acetylene production and organic solvents in wood pretreatment are likely sources.

AB - Calculations show the possibility of detecting C-14 remaining after 10 or 11 decay half-lives in natural materials, such as wood, using commercially available liquid scintillation (LS) detectors. Assuming in-situ C-14 production has contributed insignificantly to the measured C-14, one can calculate finite ages approaching 70 ka. In practice, defensible finite age determinations involve careful considerations of several critical elements in the procedure. These critical elements are: 1) the integrity of the sample itself, in terms of younger contaminants and of in situ-produced C-14; 2) the availability of ''dead'' background material; 3) chemical blank in laboratory preparation of, in this case, benzene; and 4) stability of background and efficiency of the LS counting system. High-sensitivity C-14 dating reveals a low level of memory effect C-14 in benzene synthesized in the laboratory from anthracite or marble. This level of C-14 activity is equivalent to that found in 53 ka old wood, and thus, is not distinguishable from petrochemical benzene used in routine dating. If careful control of laboratory conditions can maintain this C-14 blank constant, reproducible dating beyond 53 ka would be possible. Although we have not completed a systematic analysis of the origins of memory effect, lithium reactors used in acetylene production and organic solvents in wood pretreatment are likely sources.

KW - radiocarbon dating

KW - natural materials

KW - wood

KW - isotopic enrichment

M3 - Article

VL - 34

SP - 351

EP - 359

JO - Radiocarbon

JF - Radiocarbon

SN - 0033-8222

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