Unexpected Problems in AMS 14C Dating of Fen Peat

Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 95-108 ◽  
Author(s):  
Minna Väliranta ◽  
Markku Oinonen ◽  
Heikki Seppä ◽  
Sanna Korkonen ◽  
Sari Juutinen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Time Window ◽  
Plant Macrofossils ◽  
Carbon Accumulation ◽  
14C Dating ◽  
Plant Macrofossil ◽  
Peat Core ◽  
Ams Dating ◽  
Ams 14C Dating

Four fen peat sequences in northern Finland were dated by the accelerator mass spectrometry (AMS) radiocarbon method in order to study past peatland dynamics and carbon accumulation patterns. Initially, plant macrofossils were used for dating. However, the dates were severely disordered, with marked inversions in all sequences. In one 140-cm peat core, for example, all ages fell within a ∼1000-yr time window. Following these unreliable results, a few bulk peat samples were dated to help assess if any of the plant macrofossil-derived dates were reliable. Bulk dates did not help to solve the problem. This study evaluates the possible sources of error but is unable to single out one clear cause. It is probable that many factors related to the fen environment, such as flooding and root intrusion, may have contributed to the errors. Peat plant macrofossils and bulk peat samples are considered to be reliable dating materials, but the examples given herein highlight the difficulties that can be associated with AMS dating of peat samples.

scholarly journals Correcting for Contamination in AMS 14C Dating

Radiocarbon ◽  
2002 ◽  
Vol 44 (2) ◽  
pp. 591-595 ◽  
Author(s):  
Ken Mueller ◽  
Paul Muzikar
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
Chemical Processing ◽  
14C Dating ◽  
Two Stage ◽  
Carbon Contamination ◽  
Ams 14C Dating

When using accelerator mass spectrometry (AMS) for radiocarbon dating, it is important to correct for carbon contamination that is added to the sample and the standard during chemical processing. We derive an equation for making this correction that generalizes previous work in several ways. We treat the case in which contaminating carbon is added during both the combustion step and graphitization step. Taking this two-stage contamination process into account is particularly important when only a fraction of the CO2 produced in the combustion is graphitized. We also allow for the fact that the 13C fractions of the sample, the standard, and the contaminants may be different.

scholarly journals A Comparison of Cellulose Extraction and ABA Pretreatment Methods for AMS 14C Dating of Ancient Wood

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1371-1379 ◽  
Author(s):  
J R Southon ◽  
A L Magana
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Extraction Method ◽  
Acid Base ◽  
14C Dating ◽  
Standard Acid ◽  
Ancient Wood ◽  
Ams 14C Dating

We have compared accelerator mass spectrometry (AMS) radiocarbon results on wood samples at or near the limit of 14C dating, pretreated with a standard acid-base-acid (ABA) protocol, with those obtained from cellulose prepared from the same samples by several modifications of the Jayme-Wise cellulose extraction method (Green 1963). These tests were carried out to determine the most efficient way to ensure low backgrounds in 14C measurements of well-preserved ancient wood samples.

The Strange Case of the Ankhpakhered Mummy: Results of AMS 14C Dating

Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1403-1408
Author(s):  
G Quarta ◽  
S Malgora ◽  
M D'Elia ◽  
V Gaballo ◽  
E Braione ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
Accelerator Mass Spectrometry ◽  
Radiocarbon Dating ◽  
14C Dating ◽  
Egyptian Mummy ◽  
Ams Radiocarbon Dating ◽  
Ancient Egyptian ◽  
The University ◽  
Ams 14C Dating

The ancient Egyptian mummy discovered in the wooden coffin of Ankhpakhered, priest of the god Min, has been studied at CEDAD (Centre for Dating and Diagnostics) at the University of Salento, Italy. The CT scan, performed by the multidisciplinary team of the Mummy Project of Milan, highlighted unusual features of the mummy, suggesting a reuse of the sarcophagus. Furthermore, specimens were taken via endoscopy for accelerator mass spectrometry (AMS) radiocarbon dating and Fourier transform infrared (FTIR) analyses, which have been carried out at CEDAD.

scholarly journals A Chronology of the Pre-Columbian Paracas and Nasca Cultures in South Peru Based on AMS 14C Dating

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 551-564 ◽  
Author(s):  
Ingmar Unkel ◽  
Bernd Kromer ◽  
Markus Reindel ◽  
Lukas Wacker ◽  
Günther Wagner
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Building Material ◽  
Initial Period ◽  
Southern Coast ◽  
14C Dating ◽  
Radiocarbon Dates ◽  
The People ◽  
Absolute Dating ◽  
Ams 14C Dating

The people of the Paracas and Nasca cultures, the creators of the famous geoglyphs, lived in the desert of the southern coast of Peru between about 800 BC and AD 650. The archaeological chronology of these cultures has been based almost exclusively on a sequence of ceramic styles. The absolute dating of some of the style phases was supported by a few radiocarbon dates (Rowe 1967). Here, we present an absolute chronology of the Paracas and Nasca cultures based on 14C dating of more than 100 organic samples from settlement and tomb relics, as well as on material derived from geoglyph sites in the Nasca/Palpa region (south Peru). The main focus has been on Nasca period settlement centers near Palpa, Los Molinos and La Muña, the Paracas period site of Jauranga, and the Initial period site of Pernil Alto. Most of the 14C samples were dated at the accelerator mass spectrometry (AMS) facility of the ETH Zurich (Switzerland). The targets were produced in the newly built graphitization line at the Heidelberg 14C laboratory (Germany). Clay (adobe) bricks, which are quite a common building material in Peru, were successfully tested to be used for AMS 14C dating of adobe architecture in Peruvian archaeology.

scholarly journals A Novel Approach for Developing High-Resolution Sub-Fossil Peat Chronologies with 14C Dating

Radiocarbon ◽  
2004 ◽  
Vol 46 (1) ◽  
pp. 455-463 ◽  
Author(s):  
T H Donders ◽  
F Wagner ◽  
K van der Borg ◽  
A F M de Jong ◽  
H Visscher
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
20Th Century ◽  
Accelerator Mass Spectrometry ◽  
Meteorological Data ◽  
Time Frame ◽  
14C Dating ◽  
Novel Approach

Sub-fossil sections from a Florida wetland were accelerator mass spectrometry (AMS) dated and the sedimentological conditions were determined. 14C data were calibrated using a combined wiggle-match and 14C bomb-pulse approach. Repeatable results were obtained providing accurate peat chronologies for the last 130 calendar yr. Assessment of the different errors involved led to age models with 3–5 yr precision. This allows direct calibration of paleoenvironmental proxies with meteorological data. The time frame in which 14C dating is commonly applied can possibly be extended to include the 20th century.

scholarly journals 14C Dating of Laser-Oxidized Organics

Radiocarbon ◽  
1993 ◽  
Vol 35 (2) ◽  
pp. 331-333 ◽  
Author(s):  
A. L. Watchman ◽  
R. A. Lessard ◽  
A. J. T. Jull ◽  
L. J. Toolin ◽  
Weston Blake
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Accelerator Mass Spectrometry ◽  
14C Dating ◽  
Ion Laser ◽  
Different Parts

We used a continuous krypton ion laser to rapidly oxidize milligram-sized fragments of coniferous driftwood of known ages, and dated the resulting carbon dioxide by accelerator mass spectrometry (AMS). AMS 14C ages of non-pretreated young wood from different parts of two logs were within 10% of the ages of conventionally determined alkaline insoluble fractions. The age of the oldest whole wood measured after laser oxidation was within the error ranges of conventional values.

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.

scholarly journals Examination of Background Contamination Levels for Gas Counting and AMS Target Preparation in Trondheim

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 312-317 ◽  
Author(s):  
Steinar Gulliksen ◽  
Mette S. Thomsen
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Target Preparation ◽  
Very Old ◽  
Ams Dating ◽  
Contamination Levels ◽  
Lower Background

The Radiological Dating Laboratory in Trondheim relatively often dates samples with ages >30 ka BP. Contaminated background materials are known to affect the accuracy of very old dates. We have found, by measurements of different materials, that such contamination is small when using our conventional gas proportional counting (GPC) system. We have also studied contamination levels of our target preparation for 14C accelerator mass spectrometry (AMS) dating in Uppsala. A significant lower background is obtained for Icelandic double spar than for marbles, probably due to a crystal structure of the double spar that is more insensitive to contaminating processes. The background for combusted samples is at the same level as for samples of double spar, indicating that additional 14C contamination due to combustion is negligible. Dates obtained on interstadial samples (T >30 ka bp) by both GPC and AMS agree well.

scholarly journals Marine Turtle Bones from an Archaeological Site in Polynesia Yield Reliable Age Determinations

Radiocarbon ◽  
1990 ◽  
Vol 32 (2) ◽  
pp. 143-147 ◽  
Author(s):  
T S Dye
Keyword(s):  
Mass Spectrometry ◽  
Sample Size ◽  
Accelerator Mass Spectrometry ◽  
South Pacific ◽  
Archaeological Site ◽  
Marine Turtle ◽  
Long Distance ◽  
Marine Turtles ◽  
Ams Dating ◽  
Age Determinations

Accelerator mass spectrometry dating of three 50g samples of marine turtle bone from the basal cultural stratum of the Tongoleleka archaeological site, Lifuka Island, Kingdom of Tonga, South Pacific yields results that agree with conventional 14C dates on marine shell. A method for calibrating these dates that takes into account the long distance migrations of marine turtles in the South Pacific is proposed. A sample size greater than 50g is recommended for routine AMS dating of marine turtle bone.

scholarly journals Towards a Radiocarbon Chronology of the Late-Glacial: Sample Selection Strategies

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 1007-1019 ◽  
Author(s):  
M J C Walker ◽  
C Bryant ◽  
G R Coope ◽  
D D Harkness ◽  
J J Lowe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Sample Selection ◽  
Late Glacial ◽  
Plant Macrofossils ◽  
Sampling Strategies ◽  
Radiocarbon Dates ◽  
Selection Strategies ◽  
Beta Counting ◽  
Radiocarbon Chronology

This paper outlines a dating program designed to test the reproducibility of radiocarbon dates on different materials of Late-Glacial age (plant macrofossils, fossil beetle remains, and the “humic” and “humin” chemical fractions of limnic sediments) using a combination of radiometric (beta counting) and accelerator mass spectrometry (AMS) techniques. The results have implications for the design of sampling strategies and for the development of improved dating protocols, both of which are important if a high-precision 14C chronology for the Late-Glacial is to be achieved.

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