Zinc Reduction as an Alternative Method for AMS Radiocarbon Dating: Process Optimization at Circe

Marzaioli, Fabio; Borriello, G; Passariello, Isabella; Lubritto, Carmine; Cesare, N. De; D’Onofrio, Antonio; Terrasi, F.

doi:10.1017/s0033822200043423

Cited by 72 publications

(65 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Then the GEL fraction was obtained by heating the collagen to 70°C in a solution with pH 3 for 20 h [23]. Finally the gel was freeze-dried and used for the successive combustion and graphitization processes [24,25]. The obtained graphite was measured for the 14 C/ 12 C isotopic ratio using a NEC 3 MV accelerator mass spectrometer [26].…”

Section: Radiocarbon Datingmentioning

confidence: 99%

Convento di San Francesco a Folloni: the function of a Medieval Franciscan Friary seen through the burials

et al. 2015

View full text Add to dashboard Cite

Background:The Franciscan Friary in Montella near Avellino in Southern Italy is of special interest because according to historical sources it was founded by St. Francis himself in AD 1221-1222. Human remains of several hundred individuals interred in the cloister walk have been unearthed during two excavation campaigns conducted in 2007-2008 and 2010. The environs of the friary have remained rural since the foundation preventing much modern contamination. The state of preservation of the skeletons is fair to good making a suite of analyses worthwhile. Results:The skeletons have been examined anthropologically and tissue samples have been subjected to radiocarbon dating, stable isotope measurements and trace element analyses by Inductively Coupled Plasma Mass Spectrometry and Cold Vapour Atomic Absorption Spectrometry. Conclusions:The radiocarbon dates are consistent with the historical sources and show that the cemetery in the cloister walk has been in uninterrupted use from the foundation of the friary in AD 1221-1222 and until the cemetery went out of use in AD 1524. The anthropological investigations show that the individuals interred at the friary would have been shorter than other Italians from the same time, and it seems that tuberculosis was more prevalent than leprosy. Isotopic measurements show a mixed agricultural and pastoral diet and none of the individuals were consuming marine protein. Based on the trace element analysis it seems that the people resided mainly at two distinct geographical areas, one of which was Montella. One individual stands out from the rest, because he was born and raised at some third geographical location distinct from Montella and because he sports the second oldest radiocarbon date of AD 1050-1249 (two sigma calibrated range). This date is consistent with the first generation of the founders of the friary-perhaps one of St. Francis' fellow travellers from Assisi.

show abstract

Section: Radiocarbon Datingmentioning

confidence: 99%

Convento di San Francesco a Folloni: the function of a Medieval Franciscan Friary seen through the burials

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Pre-treatment of the Zn and TiH 2 reagents by separately baking $2 g of each reagent in vacuum-sealed Pyrex tubes (9 mm OD Â 120 mm length) at 360°C for 3 h was also attempted [7]. Neither of these treatments gave significantly improved results, with treated and control samples yielding comparatively equivalent modern-carbon background component values between 0.9 and 1.5 lg C.…”

Section: Modern-carbon Background Improvementsmentioning

confidence: 99%

“…Baking assembled reactor tubes at 300°C in open air for 1 h prior to use produced the best results with values of 0.3 lg C being observed [7]. This indicates that most of the modern-carbon background component is from adsorbed ambient CO 2 on the surface of the reagents, catalyst, and or reactor tube walls, and not from contaminating carbon inside the lattice of the Zn reagent, which would require heating to a temperature above the melting point of Zn (419.58°C) to eliminate.…”

Section: Modern-carbon Background Improvementsmentioning

confidence: 99%

Small-mass graphite preparation by sealed tube zinc reduction method for AMS 14C measurements

Khosh

Trumbore

2010

Nuclear Instruments and Methods in Physics Research Section B:

View full text Add to dashboard Cite

a b s t r a c tPrevious work has demonstrated that the sealed tube Zn reduction method for converting CO 2 to graphite for AMS 14 C measurements produces targets that can be measured with high precision and low background for samples of about 1 mg C down to approximately 0.1 mg C at the Keck Carbon Cycle AMS facility at the University of California, Irvine (KCCAMS). Now a modified method has been developed to prepare small-mass samples ranging from 0.015 to 0.1 mg C. In this modified method, the volume of the sealed reactor tube is reduced to $1.9 cm 3 , and the amounts of Zn and TiH 2 reagents are reduced proportionally. The amount of Fe catalyst used remains the same to ensure a long lasting current in the AMS. Small-mass samples prepared by this method generally yield 12 C +1 currents of about 0.5 lA per 1 lg C. An in situ simultaneous AMS d 13C measurement allows for correction of both graphitization and machineinduced isotopic fractionation, and is a prerequisite for high precision and accurate measurements using the Zn reducing method. Corrections for modern-carbon and dead-carbon background components are applied to samples based on small-mass samples of a 14 C free material and of a modern standard covering the sample size range. It was discovered during additional investigation into lowering the modern-carbon background component that baking assembled reactor tubes at 300°C for 1 h prior to use resulted in significantly lower modern-carbon background values. The accuracy and precision of small-mass samples prepared by this method are size dependent, but is usually ±10-15‰ for the smallest samples (0.015-0.02 mg C), based on duplicate measurements of primary and secondary standards.

show abstract

“…An aliquot of about 4 mg of C of each sample was chemically pre-treated to produce graphite for 14 C AMS analysis, according to Marzaioli et al (2007). Graphite was pounded into Al cathodes and measured by means of the AMS system of the CIRCE centre (Terrasi et al 2008).…”

Section: Input/standing Litter Pool Studymentioning

confidence: 99%

Inter-comparison of methods for quantifying above-ground leaf litter decomposition rates

et al. 2010

View full text Add to dashboard Cite

Above ground litter decomposition is the result of three interlinked processes: leaching, fragmentation and catabolism. Litter decomposition estimates are most commonly based on measurements of mass loss from litter residues, confined in mesh bags. This method provides a rough estimate of leaching and catabolism, while preventing fragmentation from occurring. Alternatively, litter decomposition is studied in the laboratory as microbial respiration of litter residue. In this case, generally only catabolism is measured. While those limits are often discussed, their careful assessment has never been attempted. We present here results from a study where the decomposition rate of Arbutus unedo leaf litter, at a throughfall manipulation experiment, was investigated using: 1) litterbags; 2) turnover based on litter input/standing litter pool; 3) 14 C-bomb spike; 4) laboratory incubation; 5) DayCent modeling. Aims of this study were: 1) to quantitatively assess the hypothesis that the litterbags and the laboratory incubation methods, by preventing fragmentation, overestimate above ground litter mean residence time; 2) to evaluate the ability of the above methods to capture the effects of changes in precipitation on litter decay rates. Results confirmed our hypothesis and demonstrated that the litterbag and the laboratory incubation methods do capture the effects of the water manipulation treatment on litter decay rates.

show abstract

Zinc Reduction as an Alternative Method for AMS Radiocarbon Dating: Process Optimization at Circe

Cited by 72 publications

References 32 publications

Convento di San Francesco a Folloni: the function of a Medieval Franciscan Friary seen through the burials

Convento di San Francesco a Folloni: the function of a Medieval Franciscan Friary seen through the burials

Small-mass graphite preparation by sealed tube zinc reduction method for AMS 14C measurements

Inter-comparison of methods for quantifying above-ground leaf litter decomposition rates

Contact Info

Product

Resources

About