scholarly journals Is there any Evidence for Regional Atmospheric 14C Offsets in the Southern Hemisphere?

Radiocarbon ◽  
2013 ◽  
Vol 55 (4) ◽  
pp. 2029-2034 ◽  
Author(s):  
Alan Hogg ◽  
Chris Turney ◽  
Jonathan Palmer ◽  
Ed Cook ◽  
Brendan Buckley
Keyword(s):  
Mass Spectrometry ◽  
New Zealand ◽  
Southern Hemisphere ◽  
Accelerator Mass Spectrometry ◽  
Time Interval ◽  
Common Time ◽  
Lagarostrobos Franklinii

Center for Accelerator Mass Spectrometry (CAMS) Tasmanian Huon pine (Lagarostrobos franklinii) decadal measurements for the interval AD 745–855 suggest a mean interhemispheric radiocarbon offset (20 ± 5 yr), which is considerably lower than the previously reported mean interhemispheric offset for the last 2 millennia (44 ± 17 yr). However, comparable University of Waikato (Wk) New Zealand kauri (Agathis australis) measurements show significantly higher values (56 ± 6 yr), suggesting the possibility of a temporary geographic (intrahemispheric) offset between Tasmania, Australia, and Northland, New Zealand, during at least 1 common time interval. Here, we report 9 new Wk Tasmanian Huon pine measurements from the decades showing the largest Huon/kauri difference. We show statistically indistinguishable Wk Huon and Wk kauri 14C ages, thus dispelling the suggestion of a 14C geographic offset between Tasmania and Northland.

scholarly journals High-Precision Radiocarbon Measurements of Tree-Ring Dated Wood from New Zealand: 195 Bc–Ad 995

Radiocarbon ◽  
2011 ◽  
Vol 53 (3) ◽  
pp. 529-542 ◽  
Author(s):  
Alan Hogg ◽  
Jonathan Palmer ◽  
Gretel Boswijk ◽  
Chris Turney
Keyword(s):  
New Zealand ◽  
Southern Hemisphere ◽  
Calibration Curve ◽  
Geographic Location ◽  
Temporal Variations ◽  
Time Interval ◽  
Data Sets ◽  
Data Set ◽  
Data Points ◽  
Lagarostrobos Franklinii

The best means for correcting Southern Hemisphere (SH) radiocarbon measurements, which are significantly influenced by temporal variations in the interhemispheric offset, is by the construction of a SH-specific calibration curve from dendrochronologically dated wood. We present here decadal 14C measurements on dendrochronologically secure New Zealand kauri (Agathis australis), covering the period 195 BC–AD 995, extending the range of calibration measurements from New Zealand tree rings to more than 2 millennia.Recently published Tasmanian huon pine (Lagarostrobos franklinii) data for the interval 165 BC to AD 1095 measured at the Center for Accelerator Mass Spectrometry (CAMS) have underestimated standard errors, which need to be re-assessed before the data can be considered for a Southern Hemisphere calibration curve update. The CAMS huon data, unlike the Waikato kauri data presented here, show a significant reduction in the SH offset for the interval AD 775–855. Although these data points are being checked, it is unlikely this represents a temporal geographic location-dependent offset. With re-assessed errors, the huon data set from 165 BC to AD 995 closely matches the new kauri data, with the combined data sets producing a mean interhemispheric offset with IntCal09 of 44 ± 17 yr for the time interval 195 BC–AD 1845. This SH offset is lower than the modeled offset of 55–58 yr used in the construction of SHCal04, and we recommend the lower value be used in future SHCal updates. Although there is an apparent increase in higher frequency events in the SH offset (NZ kauri plus Tasmanian huon) from 200 BC–AD 1000, the reason for this remains unclear.

scholarly journals Reliability of Bone Gelatin AMS Dating: Rattus Exulans and Marine Shell Radiocarbon Dates from Pauatahanui Midden Sites in Wellington, New Zealand

Radiocarbon ◽  
1999 ◽  
Vol 41 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Nancy Beavan Athfield ◽  
Bruce McFadgen ◽  
Rodger Sparks
Keyword(s):  
Mass Spectrometry ◽  
New Zealand ◽  
Beta Decay ◽  
Confidence Level ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dates ◽  
Austrovenus Stutchburyi ◽  
Ams Dating ◽  
Marine Shell

A suite of 6 bone gelatin accelerator mass spectrometry (AMS) radiocarbon dates for Rattus exulans Peale and associated beta decay 14C dates for Austrovenus stutchburyi shell are presented for 4 middens at Pauatahanui, Wellington, New Zealand. Mean calibrated age ranges of Rattus exulans (520–435 BP and 350–330 BP at 95% confidence level) and shell (465–375 BP at 95% confidence level) from the 4 midden sites overlap. The agreement between Rattus exulans bone gelatin dates and associated shell provides an inter-sample comparison of 14C dating using both gas counting (beta decay) and AMS dating techniques. We examine the adequacy of the standard gelatinization treatment for bone samples, which has been employed consistently at the laboratory since 1995.

Measuring 14C Concentration in Wine to Monitor Global Distribution of 14C

Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1827-1833
Author(s):  
Hirohisa Sakurai ◽  
Saori Namai ◽  
Emiko Inui ◽  
Fuyuki Tokanai ◽  
Kazuhiro Kato ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Correlation Coefficient ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Accelerator Mass Spectrometry ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Fossil Fuel ◽  
Scintillation Counting ◽  
Northern And Southern Hemispheres

Using liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS), radiocarbon concentrations were measured for wine from 8 wineries located in 7 countries in the Northern and Southern hemispheres. The 14C concentrations of ethanol and residual materials in the wine were correlated (correlation coefficient 0.82). The δ14C measurements of wine samples from the mid-latitudes in the Northern Hemisphere were approximately 1l% lower than the extrapolations from Schauinsland data, suggesting a local fossil fuel effect. δ14C measurements from the wine samples from the Southern Hemisphere were higher than those from the Northern Hemisphere. The offsets of the 4 wine δ14C measurements were significant, with values between approximately 8% and 15%. Because the harvest years of the mixed grapes were estimated to be 7–12 yr older than their vintage years, this leads to a caveat when determining the 14C concentrations of the year using the wine vintage.

scholarly journals Radiocarbon Dating of Wood Using Different Pretreatment Procedures: Application to the Chronology of Rotoehu Ash, New Zealand

Radiocarbon ◽  
2001 ◽  
Vol 43 (2A) ◽  
pp. 239-248 ◽  
Author(s):  
G M Santos ◽  
M I Bird ◽  
B Pillans ◽  
L K Fifield ◽  
B V Alloway ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
New Zealand ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Wet Oxidation ◽  
Acid Base ◽  
Acid Pretreatment ◽  
Age Range ◽  
Ams Dates

We compare radiocarbon accelerator mass spectrometry (AMS) ages of wood samples subjected to a conventional acid-base-acid pretreatment with stepped combustion (ABA-SC) with results from the same samples subjected to an acid-base-wet oxidation pretreatment with stepped combustion (ABOX-SC) and cellulose extraction with stepped combustion (CE-SC). The ABOX-SC procedure has been shown previously to lead to lower backgrounds for old charcoal samples. Analyses of relatively uncontaminated “14C-dead” samples of wood suggest that backgrounds of 0.11 ± 0.04 pMC are obtainable for both the ABOX-SC and ABA-SC procedures. Where wood is significantly contaminated the ABOX-SC technique provides significantly better decontamination than either the ABA-SC technique or cellulose extraction alone, although CE-SC can produce comparably low backgrounds to the ABOX-SC procedure.We also report the application of the ABOX-SC, ABA-SC and CE-SC procedures to wood samples associated with the chronologically controversial Rotoehu Ash eruption, New Zealand. New 14C-AMS dates from wood sampled from below the Rotoehu Ash span an age range of 43–50 ka BP consistent with recently presented OSL dates of 42–44 ka obtained for palaeosols beneath the ash.

scholarly journals Hiatus in Prehistoric Chronology of the Cis-Baikal Region, Siberia: Pattern or Artifact?

Radiocarbon ◽  
2007 ◽  
Vol 49 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Yaroslav V Kuzmin
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Baikal Region ◽  
Critical Evaluation ◽  
Burial Grounds

The problem of a hiatus at about 6100–5300 BP (about 4900–4200 cal BC) in the prehistoric chronology of the Cis-Baikal region in Siberia is discussed. Based on a critical evaluation of existing evidence, there was no discontinuity found in the cultural sequence between the Kitoi and Serovo/Glazkovo complexes of the Neolithic, and the proposed “hiatus” may be an artifact based on underestimation of solid data. Conventional 14C dates are presented that were generated in the 1980s to early 2000s for Cis-Baikal prehistoric burial grounds, and were later dated by the accelerator mass spectrometry (AMS).

scholarly journals 14C INTERCOMPARISON EXERCISE ON BONES AND IVORY SAMPLES: IMPLICATIONS FOR FORENSICS

Radiocarbon ◽  
2021 ◽  
pp. 1-12
Author(s):  
G Quarta ◽  
M Molnár ◽  
I Hajdas ◽  
L Calcagnile ◽  
I Major ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
International Atomic Energy Agency ◽  
Accelerator Mass Spectrometry ◽  
Reference Curve ◽  
Nuclear Testing ◽  
Energy Agency ◽  
Widespread Application ◽  
Intercomparison Exercise ◽  
High Degree ◽  
Data Calibration

ABSTRACT The application of accelerator mass spectrometry radiocarbon (AMS 14C) dating in forensics is made possible by the use of the large excursion of the 14C concentration in the post-WWII terrestrial atmosphere due to nuclear testing as a reference curve for data calibration. By this approach high-precision analyses are possible on samples younger than ∼70 years. Nevertheless, the routine, widespread application of the method in the practice of forensics still appears to be limited by different issues due to possible complex interpretation of the results. We present the results of an intercomparison exercise carried out in the framework of an International Atomic Energy Agency (IAEA) CRP-Coordinated Research Project between three AMS laboratories in Italy, Hungary, and Switzerland. Bone and ivory samples were selected with ages spanning from background (>50 ka) to 2018. The results obtained allow us to assess the high degree of reproducibility of the results and the remarkable consistency of the experimental determinations.

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