Paul E Damon
Datos Biográficos
| ID | 4680107 |
|---|---|
| NOMBRE | Paul E Damon |
| NOMBRES | Paul E |
| APELLIDO | Damon |
| FIRMA | DAMON P E |
| AFILIACIONES | University of Arizona |
| VERIFICADO | No |
| TOTAL DE OBRAS | 26 |
| TOTAL DE CITAS | 346 |
| TOTAL COMO AUTOR | 26 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 1959 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2004 |
| ÍNDICE H | 9 |
Marine04 Marine Radiocarbon Age Calibration, 0–26 Cal Kyr Bp
New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring…
Preliminary Report of the First Workshop of the Intcal04 Radiocarbon Calibration/Comparison Working Group
The first meeting of the IntCal04 working group took place at Queen's University Belfast from April 15 to 17, 2002. The participants are listed as co-authors of this report. The meeting considered criteria for the acceptance of data into the next official calibration dataset, the importance of including reliable estimates of uncertainty in both the radiocarbon ages and the cal ages, and potential methods for combining datasets. This preliminary r…
Radiocarbon Calibration and Application to Geophysics, Solar Physics, and Astrophysics
This paper includes a brief history of the calibration of the radiocarbon time scale from the first recognition of the necessity of calibration in 1962 to INTCAL98. Thirty-six years of effort by dendrochronologists and the 14 C community have pushed the tree-ring calibration back to 11,854 yr BP. All of this part of the calibration has been done by high-precision beta counting. Uranium-thorium (U-Th) dating of coral samples coupled with accelerat…
The Maunder Minimum
Measurements on same-age tree-ring samples from proximal Ural Mountain trees by the Ioffe Institute research group and at the University of Arizona demonstrate a variance corresponding to a standard deviation of ±5.1% for Ioffe compared to ±2.1% for Tucson. There is also a calibration difference of 4.3 ±1.2 ‰. Comparison of the same years measured in Seattle on wood from the Pacific Northwest shows an offset of 2.2 ± 0.5 ‰. This is not a calibrat…
Factors Affecting the Apparent Radiocarbon Age of Textiles
Report
Recently, in an intercomparison of the Hohenheim German oak chronology (Becker 1993) and the Göttingen chronology (Leuschner and Delorme 1988), an error was discovered in the former (Leuschner, in preparation). Due to an error in adding sections at 5241 bc, 41 yr are missing in the published Hohenheim chronology. After correction of the error, the two chronologies synchronize over their entire common length, back to 7200 bc
Note Concerning “Intercomparison of High-Precision 14 C Measurements at the University of Arizona and the Queen's University of Belfast Radiocarbon Laboratories” by Kalin et al. (1995) and the Regiona…
Although a coauthor of the paper of Kahn et al . (1995), I was not available in time to review the final copy. Consequently, I take this opportunity to make further comments and, hopefully, clarify some of the content and conclusions
Radiocarbon Production by the Gamma-Ray Component of Supernova Explosions
We selected SN1006, the brightest and closest to Earth of all supernovas historically observed, for a study of 14 C production by e − ,e + -bremsstrahlung cascades initiated by hard γ rays (>10 MeV) from that event. During the cascade, bremsstrahlung energies eventually fall within a giant (n,γ), (n,2γ) cross-section, peaking at 23 MeV and approaching effectively zero below 10 MeV and above 40 MeV. The neutrons are absorbed primarily in the react…
A Note Concerning “Location-Dependent Differences in the 14 C Content of Wood” by McCormac et al
I have read with interer .he detailed paper by 18 yr toward older dates may not be valid (Pearson and Qua 1993). They also document "evidence for small location-dependent 14C differences". In the process, they also rediscover a North American marine west coast effect that, as a reviewer of their first draft, I had pointed out to them but that they chose not to acknowledge. Specifically, we find no difference between our measurements on west coast…
Cosmogenic Isotope Paleogeophysics - Paleoastrophysics and Natural Variation of Cosmogenic Isotopes
In order to confirm the radiocarbon half-life of 5568 30 years, based upon then available measurements, Willard Libby (1955) produced the first calibration of the radiocarbon time scale, using samples of known age dating back to 5000 BC. He concluded that this half-life was valid and that the 14C/12C ratio of atmospheric CO2 was sufficiently constant to permit accurate dating of paleoevents. A few years later, this assumption was brought into que…
Fine and Hyperfine Structure in the Spectrum of Secular Variations of Atmospheric 14C
The coarse structure of the 14 C spectrum consists of a secular trend curve that may be closely fit by a sinusoidal curve with period ca 11,000 yr and half amplitude ±51. This long-term trend is the result of changes in the earth's geomagnetic dipole moment. Consequently, it modulates solar components of the 14 C spectrum but does not appear to modulate a component of the spectrum of ca 2300-yr period. The ca 2300-yr period is of uncertain origin…
Global Production and Decay of Radiocarbon
The production rate of 14 C during the Holocene averaged 2.4 ± 0.2 atoms 14 C/cm e 2 sec. Neutrons produced by galactic cosmic rays account for 90% of the 14 C production with the remaining 10% resulting from neutrons produced by protons from solar flares. Production and decay of 14 C can be reconciled by including 14 C permanently or temporarily stored in sediments. Sedimentary reservoirs contain ca 30% of all terrestrial 14 C. The lagoons, bays…
High-Precision Radiocarbon Dating of Bristlecone Pine from 6554 to 5350 BC
New results of radiocarbon dating of ca 100 decadal bristlecone pine samples from 6554 BC to 6084 BC and from 5820 to 5350 BC are presented. Using 3 new 2.5L counters filled to ca 3atm with carbon dioxide, high-precision dating has been performed by this laboratory for more than two years. Demonstration of the precision and accuracy of these counters is presented using ±2‰ measurements from the Spörer minimum period. For the older samples, ±3‰ me…
Geomagnetic-Heliomagnetic Modulation of Atmospheric Radiocarbon Production
New Arizona high precision Δ 14 C data back to 6500 BC plot close to an 11,300-yr period sinusoid extrapolated from the post 5300 BC data (offset = +32‰, half amplitude = 51‰ and phase lag = 2.29 radians). The trend curve is modulated by high latitude components of the non-dipole field with a fundamental period of 2400 yr. Based upon a model of Lund and Banerjee (1985), the non-dipole field rotates and every 1200 yr the high latitude maxima pass …
Twelfth International Radiocarbon Conference After Dinner Remarks
The 12th International Radiocarbon Conference has been a success! To paraphrase Francis Bacon's words in his treatise, "The Novuum Organum," we have gathered together as true sons and daughters of knowledge "to overcome not an adversary in argument but nature in action"; and we have enjoyed good fellowship in the process. I feel strongly in a conference such as this that we, in our science, are a great international fraternity joined together as …
The Concept of DC Gain in Modeling Secular Variations in Atmospheric 14 C
A constraint on radiocarbon reservoir models is that the DC gain of a system (system transfer function at zero frequency) should equal the equilibrium ratio of the atmospheric radiocarbon mass to the production rate. The simple one-box model is essentially a “black box” but the value of the single residence time is theoretically equal to the DC gain. Using a sunspot-production rate algorithm as the forcing function, predictions of the one-box mod…
Radiocarbon Concentration in the Atmosphere
Radiocarbon dates calculated from the ratio of modern carbon-14 activity and sample activity and the half-life of carbon-14 need to be calibrated to compensate for temporal variations in the concentration of carbon-14 in the atmosphere. Development of a suitable calibration scheme has been an ongoing process of the last twenty years, ever since the discovery of variations in historical times of the atmospheric radiocarbon content which parallel c…
Dendrochronologic Calibration of the Radiocarbon Time Scale
Extensive radiocarbon analyses have been made of dendrochronologically dated wood. The resultant radiocarbon data are not in total agreement with the conventional solar calendar as exemplified by the tree-ring chronology. The discrepancy reaches a maximum between 4060 B.C. to 7350 B.C. when radiocarbon dates are too young by 800 to 870 yr. Using a compatible set of 549 dated samples as a working base, a calibration table has been derived for conv…
Vi. Sunspots a N D Radiocarbon Dating in the Middle Ages
Arizona Radiocarbon Dates VII
The C 14 measurements reported here were made in this laboratory between November 15, 1965 and June 15, 1966. Sample descriptions are classified as follows: I. Geochemical Samples II. Geologic-Paleoclimatic Samples III. Early Man-Alluvial Stratigraphy Samples IV. Archaeologic Samples
Arizona Radiocarbon Dates VI
The C 14 measurements reported here were made in this laboratory between November 1, 1963 and November 15, 1965. Sample descriptions are classified as follows: I. Geochemical Samples II. Geologic-Paleoclimatic Samples III. Early Man-Alluvial Stratigraphy Samples IV. Archaeologic Samples
The Potassium-Argon Dating of Late Cenozoic Rocks in East Africa and Italy [and Comments and Reply]
A technique for the potassium-argon dating of high potassium feldspars of less than 50,000 years age is described. The technique is applied to the obtaining of high precision ages in the time-range 60,000-2,000,000 years. Sufficient data are presented to show that the time-scale of Plio-Pleistocene glaciations is greater than 10 years and that the time-scale of hominoids capable of fashioning tools by the working of stone is at least 1.75 10 year…
Arizona Radiocarbon Dates V
With few exceptions the C 14 measurements reported here were made in this laboratory between October 1, 1962 and November 1, 1963
Arizona Radiocarbon Dates IV
C 14 measurements reported here were made in this laboratory between December 1, 1961 and October 1, 1962. Sample descriptions are classified as follows: I. Tree-ring dated samples. II. Modern shells from Santa Barbara County, California. III. Archaeologic samples. IV. Palynologic samples. V. Geologic samples. VI. C 14 content of caliche. VII. Water samples. VIII. Modern organic sample
Arizona Radiocarbon Dates III
Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison o…
Marine04 Marine Radiocarbon Age Calibration, 0–26 Cal Kyr Bp
New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring…
The Potassium-Argon Dating of Late Cenozoic Rocks in East Africa and Italy [and Comments and Reply]
A technique for the potassium-argon dating of high potassium feldspars of less than 50,000 years age is described. The technique is applied to the obtaining of high precision ages in the time-range 60,000-2,000,000 years. Sufficient data are presented to show that the time-scale of Plio-Pleistocene glaciations is greater than 10 years and that the time-scale of hominoids capable of fashioning tools by the working of stone is at least 1.75 10 year…
High-Precision Radiocarbon Dating of Bristlecone Pine from 6554 to 5350 BC
New results of radiocarbon dating of ca 100 decadal bristlecone pine samples from 6554 BC to 6084 BC and from 5820 to 5350 BC are presented. Using 3 new 2.5L counters filled to ca 3atm with carbon dioxide, high-precision dating has been performed by this laboratory for more than two years. Demonstration of the precision and accuracy of these counters is presented using ±2‰ measurements from the Spörer minimum period. For the older samples, ±3‰ me…
Dendrochronologic Calibration of the Radiocarbon Time Scale
Extensive radiocarbon analyses have been made of dendrochronologically dated wood. The resultant radiocarbon data are not in total agreement with the conventional solar calendar as exemplified by the tree-ring chronology. The discrepancy reaches a maximum between 4060 B.C. to 7350 B.C. when radiocarbon dates are too young by 800 to 870 yr. Using a compatible set of 549 dated samples as a working base, a calibration table has been derived for conv…
Arizona Radiocarbon Dates III
Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison o…
Fine and Hyperfine Structure in the Spectrum of Secular Variations of Atmospheric 14C
The coarse structure of the 14 C spectrum consists of a secular trend curve that may be closely fit by a sinusoidal curve with period ca 11,000 yr and half amplitude ±51. This long-term trend is the result of changes in the earth's geomagnetic dipole moment. Consequently, it modulates solar components of the 14 C spectrum but does not appear to modulate a component of the spectrum of ca 2300-yr period. The ca 2300-yr period is of uncertain origin…
Arizona Radiocarbon Dates VI
The C 14 measurements reported here were made in this laboratory between November 1, 1963 and November 15, 1965. Sample descriptions are classified as follows: I. Geochemical Samples II. Geologic-Paleoclimatic Samples III. Early Man-Alluvial Stratigraphy Samples IV. Archaeologic Samples
Arizona Radiocarbon Dates IV
C 14 measurements reported here were made in this laboratory between December 1, 1961 and October 1, 1962. Sample descriptions are classified as follows: I. Tree-ring dated samples. II. Modern shells from Santa Barbara County, California. III. Archaeologic samples. IV. Palynologic samples. V. Geologic samples. VI. C 14 content of caliche. VII. Water samples. VIII. Modern organic sample
Preliminary Report of the First Workshop of the Intcal04 Radiocarbon Calibration/Comparison Working Group
The first meeting of the IntCal04 working group took place at Queen's University Belfast from April 15 to 17, 2002. The participants are listed as co-authors of this report. The meeting considered criteria for the acceptance of data into the next official calibration dataset, the importance of including reliable estimates of uncertainty in both the radiocarbon ages and the cal ages, and potential methods for combining datasets. This preliminary r…
Radiocarbon Concentration in the Atmosphere
Radiocarbon dates calculated from the ratio of modern carbon-14 activity and sample activity and the half-life of carbon-14 need to be calibrated to compensate for temporal variations in the concentration of carbon-14 in the atmosphere. Development of a suitable calibration scheme has been an ongoing process of the last twenty years, ever since the discovery of variations in historical times of the atmospheric radiocarbon content which parallel c…
Radiocarbon Calibration and Application to Geophysics, Solar Physics, and Astrophysics
This paper includes a brief history of the calibration of the radiocarbon time scale from the first recognition of the necessity of calibration in 1962 to INTCAL98. Thirty-six years of effort by dendrochronologists and the 14 C community have pushed the tree-ring calibration back to 11,854 yr BP. All of this part of the calibration has been done by high-precision beta counting. Uranium-thorium (U-Th) dating of coral samples coupled with accelerat…
Report
Recently, in an intercomparison of the Hohenheim German oak chronology (Becker 1993) and the Göttingen chronology (Leuschner and Delorme 1988), an error was discovered in the former (Leuschner, in preparation). Due to an error in adding sections at 5241 bc, 41 yr are missing in the published Hohenheim chronology. After correction of the error, the two chronologies synchronize over their entire common length, back to 7200 bc
Radiocarbon Production by the Gamma-Ray Component of Supernova Explosions
We selected SN1006, the brightest and closest to Earth of all supernovas historically observed, for a study of 14 C production by e − ,e + -bremsstrahlung cascades initiated by hard γ rays (>10 MeV) from that event. During the cascade, bremsstrahlung energies eventually fall within a giant (n,γ), (n,2γ) cross-section, peaking at 23 MeV and approaching effectively zero below 10 MeV and above 40 MeV. The neutrons are absorbed primarily in the react…
Factors Affecting the Apparent Radiocarbon Age of Textiles
A Note Concerning “Location-Dependent Differences in the 14 C Content of Wood” by McCormac et al
I have read with interer .he detailed paper by 18 yr toward older dates may not be valid (Pearson and Qua 1993). They also document "evidence for small location-dependent 14C differences". In the process, they also rediscover a North American marine west coast effect that, as a reviewer of their first draft, I had pointed out to them but that they chose not to acknowledge. Specifically, we find no difference between our measurements on west coast…
Arizona Radiocarbon Dates V
With few exceptions the C 14 measurements reported here were made in this laboratory between October 1, 1962 and November 1, 1963
Arizona Radiocarbon Dates VII
The C 14 measurements reported here were made in this laboratory between November 15, 1965 and June 15, 1966. Sample descriptions are classified as follows: I. Geochemical Samples II. Geologic-Paleoclimatic Samples III. Early Man-Alluvial Stratigraphy Samples IV. Archaeologic Samples
The Concept of DC Gain in Modeling Secular Variations in Atmospheric 14 C
A constraint on radiocarbon reservoir models is that the DC gain of a system (system transfer function at zero frequency) should equal the equilibrium ratio of the atmospheric radiocarbon mass to the production rate. The simple one-box model is essentially a “black box” but the value of the single residence time is theoretically equal to the DC gain. Using a sunspot-production rate algorithm as the forcing function, predictions of the one-box mod…
The Maunder Minimum
Measurements on same-age tree-ring samples from proximal Ural Mountain trees by the Ioffe Institute research group and at the University of Arizona demonstrate a variance corresponding to a standard deviation of ±5.1% for Ioffe compared to ±2.1% for Tucson. There is also a calibration difference of 4.3 ±1.2 ‰. Comparison of the same years measured in Seattle on wood from the Pacific Northwest shows an offset of 2.2 ± 0.5 ‰. This is not a calibrat…
Global Production and Decay of Radiocarbon
The production rate of 14 C during the Holocene averaged 2.4 ± 0.2 atoms 14 C/cm e 2 sec. Neutrons produced by galactic cosmic rays account for 90% of the 14 C production with the remaining 10% resulting from neutrons produced by protons from solar flares. Production and decay of 14 C can be reconciled by including 14 C permanently or temporarily stored in sediments. Sedimentary reservoirs contain ca 30% of all terrestrial 14 C. The lagoons, bays…
Geomagnetic-Heliomagnetic Modulation of Atmospheric Radiocarbon Production
New Arizona high precision Δ 14 C data back to 6500 BC plot close to an 11,300-yr period sinusoid extrapolated from the post 5300 BC data (offset = +32‰, half amplitude = 51‰ and phase lag = 2.29 radians). The trend curve is modulated by high latitude components of the non-dipole field with a fundamental period of 2400 yr. Based upon a model of Lund and Banerjee (1985), the non-dipole field rotates and every 1200 yr the high latitude maxima pass …
University of Arizona Radiocarbon Dates II
The radiocarbon age measurements reported on in this article were made during a period from May, 1957, through May, 1958. During this time the laboratory was operated by the Department of Anthropology, under the direction of Dr. Emil W. Haury. On July 1, 1958, the Carbon-14 laboratory, under the supervision of Dr. Paul E. Damon with Dick Shutler, Jr. as laboratory technician, was transferred to the Geochronology Laboratories
University of Arizona Radiocarbon Dates II
The radiocarbon age measurements reported on in this article were made during a period from May, 1957, through May, 1958. During this time the laboratory was operated by the Department of Anthropology, under the direction of Dr. Emil W. Haury. On July 1, 1958, the Carbon-14 laboratory, under the supervision of Dr. Paul E. Damon with Dick Shutler, Jr. as laboratory technician, was transferred to the Geochronology Laboratories
Arizona Radiocarbon Dates III
Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison o…
Arizona Radiocarbon Dates IV
C 14 measurements reported here were made in this laboratory between December 1, 1961 and October 1, 1962. Sample descriptions are classified as follows: I. Tree-ring dated samples. II. Modern shells from Santa Barbara County, California. III. Archaeologic samples. IV. Palynologic samples. V. Geologic samples. VI. C 14 content of caliche. VII. Water samples. VIII. Modern organic sample
Arizona Radiocarbon Dates V
With few exceptions the C 14 measurements reported here were made in this laboratory between October 1, 1962 and November 1, 1963
The Potassium-Argon Dating of Late Cenozoic Rocks in East Africa and Italy [and Comments and Reply]
A technique for the potassium-argon dating of high potassium feldspars of less than 50,000 years age is described. The technique is applied to the obtaining of high precision ages in the time-range 60,000-2,000,000 years. Sufficient data are presented to show that the time-scale of Plio-Pleistocene glaciations is greater than 10 years and that the time-scale of hominoids capable of fashioning tools by the working of stone is at least 1.75 10 year…
Arizona Radiocarbon Dates VI
The C 14 measurements reported here were made in this laboratory between November 1, 1963 and November 15, 1965. Sample descriptions are classified as follows: I. Geochemical Samples II. Geologic-Paleoclimatic Samples III. Early Man-Alluvial Stratigraphy Samples IV. Archaeologic Samples
Arizona Radiocarbon Dates VII
The C 14 measurements reported here were made in this laboratory between November 15, 1965 and June 15, 1966. Sample descriptions are classified as follows: I. Geochemical Samples II. Geologic-Paleoclimatic Samples III. Early Man-Alluvial Stratigraphy Samples IV. Archaeologic Samples
Vi. Sunspots a N D Radiocarbon Dating in the Middle Ages
Dendrochronologic Calibration of the Radiocarbon Time Scale
Extensive radiocarbon analyses have been made of dendrochronologically dated wood. The resultant radiocarbon data are not in total agreement with the conventional solar calendar as exemplified by the tree-ring chronology. The discrepancy reaches a maximum between 4060 B.C. to 7350 B.C. when radiocarbon dates are too young by 800 to 870 yr. Using a compatible set of 549 dated samples as a working base, a calibration table has been derived for conv…
The Concept of DC Gain in Modeling Secular Variations in Atmospheric 14 C
A constraint on radiocarbon reservoir models is that the DC gain of a system (system transfer function at zero frequency) should equal the equilibrium ratio of the atmospheric radiocarbon mass to the production rate. The simple one-box model is essentially a “black box” but the value of the single residence time is theoretically equal to the DC gain. Using a sunspot-production rate algorithm as the forcing function, predictions of the one-box mod…
Radiocarbon Concentration in the Atmosphere
Radiocarbon dates calculated from the ratio of modern carbon-14 activity and sample activity and the half-life of carbon-14 need to be calibrated to compensate for temporal variations in the concentration of carbon-14 in the atmosphere. Development of a suitable calibration scheme has been an ongoing process of the last twenty years, ever since the discovery of variations in historical times of the atmospheric radiocarbon content which parallel c…
High-Precision Radiocarbon Dating of Bristlecone Pine from 6554 to 5350 BC
New results of radiocarbon dating of ca 100 decadal bristlecone pine samples from 6554 BC to 6084 BC and from 5820 to 5350 BC are presented. Using 3 new 2.5L counters filled to ca 3atm with carbon dioxide, high-precision dating has been performed by this laboratory for more than two years. Demonstration of the precision and accuracy of these counters is presented using ±2‰ measurements from the Spörer minimum period. For the older samples, ±3‰ me…
Geomagnetic-Heliomagnetic Modulation of Atmospheric Radiocarbon Production
New Arizona high precision Δ 14 C data back to 6500 BC plot close to an 11,300-yr period sinusoid extrapolated from the post 5300 BC data (offset = +32‰, half amplitude = 51‰ and phase lag = 2.29 radians). The trend curve is modulated by high latitude components of the non-dipole field with a fundamental period of 2400 yr. Based upon a model of Lund and Banerjee (1985), the non-dipole field rotates and every 1200 yr the high latitude maxima pass …
Twelfth International Radiocarbon Conference After Dinner Remarks
The 12th International Radiocarbon Conference has been a success! To paraphrase Francis Bacon's words in his treatise, "The Novuum Organum," we have gathered together as true sons and daughters of knowledge "to overcome not an adversary in argument but nature in action"; and we have enjoyed good fellowship in the process. I feel strongly in a conference such as this that we, in our science, are a great international fraternity joined together as …
Fine and Hyperfine Structure in the Spectrum of Secular Variations of Atmospheric 14C
The coarse structure of the 14 C spectrum consists of a secular trend curve that may be closely fit by a sinusoidal curve with period ca 11,000 yr and half amplitude ±51. This long-term trend is the result of changes in the earth's geomagnetic dipole moment. Consequently, it modulates solar components of the 14 C spectrum but does not appear to modulate a component of the spectrum of ca 2300-yr period. The ca 2300-yr period is of uncertain origin…
Global Production and Decay of Radiocarbon
The production rate of 14 C during the Holocene averaged 2.4 ± 0.2 atoms 14 C/cm e 2 sec. Neutrons produced by galactic cosmic rays account for 90% of the 14 C production with the remaining 10% resulting from neutrons produced by protons from solar flares. Production and decay of 14 C can be reconciled by including 14 C permanently or temporarily stored in sediments. Sedimentary reservoirs contain ca 30% of all terrestrial 14 C. The lagoons, bays…
Cosmogenic Isotope Paleogeophysics - Paleoastrophysics and Natural Variation of Cosmogenic Isotopes
In order to confirm the radiocarbon half-life of 5568 30 years, based upon then available measurements, Willard Libby (1955) produced the first calibration of the radiocarbon time scale, using samples of known age dating back to 5000 BC. He concluded that this half-life was valid and that the 14C/12C ratio of atmospheric CO2 was sufficiently constant to permit accurate dating of paleoevents. A few years later, this assumption was brought into que…
Note Concerning “Intercomparison of High-Precision 14 C Measurements at the University of Arizona and the Queen's University of Belfast Radiocarbon Laboratories” by Kalin et al. (1995) and the Regiona…
Although a coauthor of the paper of Kahn et al . (1995), I was not available in time to review the final copy. Consequently, I take this opportunity to make further comments and, hopefully, clarify some of the content and conclusions
Radiocarbon Production by the Gamma-Ray Component of Supernova Explosions
We selected SN1006, the brightest and closest to Earth of all supernovas historically observed, for a study of 14 C production by e − ,e + -bremsstrahlung cascades initiated by hard γ rays (>10 MeV) from that event. During the cascade, bremsstrahlung energies eventually fall within a giant (n,γ), (n,2γ) cross-section, peaking at 23 MeV and approaching effectively zero below 10 MeV and above 40 MeV. The neutrons are absorbed primarily in the react…
A Note Concerning “Location-Dependent Differences in the 14 C Content of Wood” by McCormac et al
I have read with interer .he detailed paper by 18 yr toward older dates may not be valid (Pearson and Qua 1993). They also document "evidence for small location-dependent 14C differences". In the process, they also rediscover a North American marine west coast effect that, as a reviewer of their first draft, I had pointed out to them but that they chose not to acknowledge. Specifically, we find no difference between our measurements on west coast…
Factors Affecting the Apparent Radiocarbon Age of Textiles
Report
Recently, in an intercomparison of the Hohenheim German oak chronology (Becker 1993) and the Göttingen chronology (Leuschner and Delorme 1988), an error was discovered in the former (Leuschner, in preparation). Due to an error in adding sections at 5241 bc, 41 yr are missing in the published Hohenheim chronology. After correction of the error, the two chronologies synchronize over their entire common length, back to 7200 bc
The Maunder Minimum
Measurements on same-age tree-ring samples from proximal Ural Mountain trees by the Ioffe Institute research group and at the University of Arizona demonstrate a variance corresponding to a standard deviation of ±5.1% for Ioffe compared to ±2.1% for Tucson. There is also a calibration difference of 4.3 ±1.2 ‰. Comparison of the same years measured in Seattle on wood from the Pacific Northwest shows an offset of 2.2 ± 0.5 ‰. This is not a calibrat…
Radiocarbon Calibration and Application to Geophysics, Solar Physics, and Astrophysics
This paper includes a brief history of the calibration of the radiocarbon time scale from the first recognition of the necessity of calibration in 1962 to INTCAL98. Thirty-six years of effort by dendrochronologists and the 14 C community have pushed the tree-ring calibration back to 11,854 yr BP. All of this part of the calibration has been done by high-precision beta counting. Uranium-thorium (U-Th) dating of coral samples coupled with accelerat…
Preliminary Report of the First Workshop of the Intcal04 Radiocarbon Calibration/Comparison Working Group
The first meeting of the IntCal04 working group took place at Queen's University Belfast from April 15 to 17, 2002. The participants are listed as co-authors of this report. The meeting considered criteria for the acceptance of data into the next official calibration dataset, the importance of including reliable estimates of uncertainty in both the radiocarbon ages and the cal ages, and potential methods for combining datasets. This preliminary r…
Radiocarbon dating (23 obras) · Geology (21 obras) · Archaeology and ancient environmental studies (17 obras) · Paleontology (17 obras) · Archaeology (14 obras) · Geography (14 obras) · Geology and Paleoclimatology Research (13 obras) · Physics (11 obras) · Calibration (7 obras) · Tree-ring climate responses (7 obras)