scholarly journals The Roman amphitheatre in Mérida, Spain ˗Augustan or Flavian? Radiocarbon dating results on mortar carbonate

2020 ◽  
Vol 47 (1) ◽  
pp. 187-195
Author(s):  
Alf Lindroos ◽  
Jan Heinemeier ◽  
Åsa Ringbom ◽  
Thomas Schrøder Daugbjerg ◽  
Irka Hajdas
Keyword(s):  
Carbon Dioxide ◽  
Phosphoric Acid ◽  
Radiocarbon Dating ◽  
Lime Mortar ◽  
Carbon Contamination ◽  
Early Stages ◽  
Hydrolysis Process ◽  
Dating Methods

AbstractFour lime mortar samples from the Mérida amphitheatre in Spain were dated in 2001 and re-dated in 2019 with refined dating methods and focus on carbon dioxide that was released in late CO2 fractions when dissolved in phosphoric acid. The samples were difficult to date because they contained highly soluble, young carbonate contamination that dominated the carbon dioxide from the early stages of the reaction with the acid in the hydrolysis process. They were also rather hydraulic and rich in magnesium, which could have caused delayed hardening. However, there was very little dead carbon contamination so that late carbon dioxide fraction gave uniform 14C ages, pointing to a late 1st c. AD Flavian, or later age of the amphitheatre.

Delayed Hardening and Reactivation of Binder Calcite, Common Problems in Radiocarbon Dating of Lime Mortars

Radiocarbon ◽  
2020 ◽  
Vol 62 (3) ◽  
pp. 565-577 ◽  
Author(s):  
Alf Lindroos ◽  
Åsa Ringbom ◽  
Jan Heinemeier ◽  
Irka Hajdas ◽  
Jesper Olsen
Keyword(s):  
Carbon Dioxide ◽  
Phosphoric Acid ◽  
Calcium Hydroxide ◽  
Radiocarbon Dating ◽  
Lime Mortars ◽  
Dating Method ◽  
Common Problems

ABSTRACTWhen sampling mortars for radiocarbon (14C) dating it is crucial to ensure that the sample has hardened rapidly relative the resolution of the dating method. Soft and porous lime mortars usually fulfill this criterion if the samples are taken from an uncovered surface from less than a few centimeters deep. However, hard, concrete-like mortars may be impermeable for carbon dioxide and even the outermost centimeters may still contain uncarbonated calcium hydroxide. These mortars may harden very slowly and contain carbonate that formed centuries or even millennia after the original building phase, and they can still be alkaline and capture modern 14C, causing younger 14C ages than the actual construction age. Another problem is reactivation of the binder carbonate if it has been partly decarbonated during a fire later on in its history. It will be shown that these young carbonates dissolve rapidly in phosphoric acid and in many cases a reasonable 14C age can be read from 14C profiles in sequential dissolution if the measurements from initially formed carbon dioxide are disregarded. However, if a mortar was made waterproof deliberately by adding crushed or ground tile, as in Roman cocciopesto mortars, it may be very difficult to get a conclusive dating.

Carbon dioxide requirement of Neisseria gonorrhoeae growing on a solid medium

1976 ◽  
Vol 4 (2) ◽  
pp. 129-132
Author(s):  
D J Platt
Keyword(s):  
Carbon Dioxide ◽  
Neisseria Gonorrhoeae ◽  
Rapid Growth ◽  
Solid Medium ◽  
Colony Growth ◽  
Growth Cycle ◽  
Lag Phase ◽  
Replica Plating ◽  
Early Stages ◽  
Male Patients

A survey of 120 isolations of Neisseria gonorrhoeae from male patients showed that 47 (39%) isolates were unable to produce visible colonies without a supply of exogenous carbon dioxide. Of 63 strains, 25 strains required CO2 for isolation but none exhibited a CO2 requirement beyond subculture 4. CO2-requiring strains deprived of CO2 appeared to lose their colony-forming ability exponentially in an environment otherwise conductive to growth. The CO2 requirement was found to be linked to the initiation of growth. An agar-to-agar replica-plating device was used to study the early stages of colonial growth. The CO2 requirement was also found to correlate with the various phases of the colony growth cycle, such that it was required during lag phase, not required during the phase of rapid growth, and returned as colonies aged. These results are discussed.

scholarly journals Suitability of Ostrich Eggshell for Radiocarbon Dating

Radiocarbon ◽  
2001 ◽  
Vol 43 (1) ◽  
pp. 133-137 ◽  
Author(s):  
John C Vogel ◽  
Ebbie Visser ◽  
Annemarie Fuls
Keyword(s):  
Radiocarbon Dating ◽  
Archaeological Sites ◽  
Carbon Contamination ◽  
Suitable Material ◽  
Ostrich Eggshell

Ostrich eggshell from archaeological sites remains largely free of more recent carbon contamination and as such is suitable material for radiocarbon dating. The carbonate fraction of the shell does, however, display an initial deficit in 14C, which causes the ages to appear 180 ± 120 yr too old.

THE AEROBIC DECOMPOSITION OF GLUCOSE IN PODSOL SOILS

1939 ◽  
Vol 17c (4) ◽  
pp. 109-124 ◽  
Author(s):  
P. H. H. Gray ◽  
C. B. Taylor
Keyword(s):  
Carbon Dioxide ◽  
Biological Activity ◽  
Carbon Dioxide Production ◽  
Potassium Nitrate ◽  
Food Material ◽  
Early Stages ◽  
Aerobic Decomposition ◽  
Micro Organisms

The decomposition of glucose in samples from cultivated podsol soils of the Appalachian upland region of Quebec Province was effected rapidly by aerobic micro-organisms without the aid of added nitrogen. Potassium nitrate stimulated the rate of carbon dioxide production from glucose added to soil; the rate increased chiefly during the early stages while glucose was still present, and bacterial numbers were rising. Fungi developed high numbers later than the bacteria; they developed especially in soil to which glycine was added with the glucose. Biological activity was stimulated in soils in which glucose had previously been decomposed. The decomposition of the glucose appears to release other sources of available food material.

scholarly journals AMS Radiocarbon Dating of Ice: Validity of the Technique and the Problem of Cosmogenic In-Situ Production in Polar Ice Cores

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 431-435 ◽  
Author(s):  
A. T. Wilson ◽  
D. J. Donahue
Keyword(s):  
Carbon Dioxide ◽  
Radiocarbon Dating ◽  
Ice Cores ◽  
Polar Ice ◽  
Ams Radiocarbon Dating ◽  
In Situ Production ◽  
Sublimation Technique

In the “sublimation technique,” carbon dioxide entrapped in ice is recovered by sublimation, converted to graphite and ratio of 14C/13C in the CO2 determined by AMS measurements. We describe here several experiments performed to check the validity of such measurements and to study the effect of cosmogenically produced in-situ14C on the measurements.

scholarly journals Impregnation of poly(L-lactide-ran-δ-valerolactone) with essential bark oil using supercritical carbon dioxide

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chikara Tsutsumi ◽  
Souta Manabe ◽  
Susumu Nakayama ◽  
Yuushou Nakayama ◽  
Takeshi Shiono
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Azeotropic Distillation ◽  
Proteinase K ◽  
High Yield ◽  
Feed Ratio ◽  
One Pot ◽  
Molecular Weights ◽  
Hydrolysis Process ◽  
Supercritical Carbon

Abstract This work studied the incorporation of essential bark oil from Thujopsis dolabrata var. hondae, which is known to repel various insects, in poly(L-lactide-ran-δ-valerolactone) [poly(L-LA-ran-VL)] using supercritical carbon dioxide (scCO2). The poly(L-LA-ran-VL) was synthesized by first purifying the monomers by azeotropic distillation with benzene, followed by polymerization with Sn(oct)2 using the same equipment, representing an efficient one-pot process. The copolymerization of L-LA with VL using this technique at a feed ratio of 90/10 mol/mol gave poly(L-LA-ran-VL) (91/9) with a molecular weight of 6.48 × 104 g/mol and a high yield of 74.9%. Products with molecular weights over 5.0 × 104 g/mol were obtained at L-LA feed proportions of 70 to 90%. Impregnation trials were conducted between 40 and 120 °C at 14 MPa for 3 h. The oil content of a 73/27 specimen was found to increase significantly during processing at 100 or 120 °C. During enzymatic degradation with proteinase K, the 91/9 specimen showed the fastest degradation rate. Although the 71/29 sample was slowly hydrolyzed in a phosphate buffer at pH 7.0, the release of oil vapor from this material was slightly higher than that from the 91/9 specimen, and the vapor release rate continuously increased throughout the hydrolysis process.

scholarly journals Radiocarbon dating of methane and carbon dioxide evaded from a temperate peatland stream

2012 ◽  
Vol 114 (1-3) ◽  
pp. 213-223 ◽  
Author(s):  
M. H. Garnett ◽  
S. M. L. Hardie ◽  
C. Murray ◽  
M. F. Billett
Keyword(s):  
Carbon Dioxide ◽  
Radiocarbon Dating
Sign in / Sign up

Export Citation Format

Share Document