Accelerator Mass Spectrometry 14C Measurements Research Articles

AMS 14C Dating at the Scottish Universities Environmental Research Centre (SUERC) Radiocarbon Dating Laboratory

AbstractThis paper describes all the major procedures adopted by the Scottish Universities Environmental Research Centre (SUERC) Radiocarbon Dating Laboratory. This includes sample pretreatment, graphite production, accelerator mass spectrometry (AMS) measurement, associated stable isotope measurements, data handling, and age calculations, but with the main emphasis being on the chemical pretreatment methods. All of the above enable the laboratory to provide a complete analytical service comprising advice on sample selection, preparation and analysis of samples, and Bayesian analysis of resulting 14C (and other) data. This applies to both our research and commercial activities. The pretreatment methods that we mainly focus on are used to remove contaminant carbon from a range of sample types or to isolate a particular chemical fraction from a sample prior to combustion/hydrolysis, graphitization, and subsequent AMS 14C measurement. The methods described are for bone (collagen extraction, with and without ultrafiltration), cremated bone, tooth enamel, charcoal, grain, carbon residues, shell, wood (including alpha-cellulose isolation), peat, sediments, textiles, fuel/biofuel, and forensic samples.

Stable nitrogen isotope record of lacustrine sediments in Lake Onuma (Northern Japan) indicates regional hydrological variability during the past four centuries

Discriminating natural and anthropogenic forcing on hydroclimatic changes is of fundamental importance for projecting future precipitation distribution under the warming climate. A sediment core (ON12C) obtained from Lake Onuma is used to study the evolution of precipitation in Northern Japan. The age-depth model for the core is based on three identified tephra layers, combined with accelerator mass spectrometry 14C measurements of plant remnants, 137Cs dating, and lithology. Multi-proxy records, including pollen concentration, Alnus pollen percentages and C/N atomic ratios, indicate that the δ15N record reflects nitrogen availability in the catchment where precipitation may exert a significant impact. The δ15N record shows that the precipitation was gradually increasing from 1640 AD, reaching peak strength in the middle of the 19th century, followed by a dry interval during the 20th century. The reconstructed variability in the precipitation from Lake Onuma is supported by other precipitation records from the Asian monsoon region. Solar irradiance is likely responsible for the changes in the summer monsoon precipitation on the centennial timescales during the late Little Ice Age, and the winter monsoon may also have played an important role in snow precipitation. However, the 20th century anomaly indicates that the Asian summer monsoon precipitation variability might be affected by anthropogenic forcing.

High-precision age determination of Holocene samples by radiocarbon dating with accelerator mass spectrometry at Nagoya University

Age determination with high accuracy as well as high resolution is a principal procedure in the research of Quaternary processes, such as volcanic eruptions, lacustrine and ocean sedimentation, and recent fault activation, for investigating past global environmental changes and predicting the realistic changes in the near future. Among several dating techniques applicable to late Quaternary samples, radiocarbon dating has been commonly used since 1950, although its application is limited to ages younger than ca. 50 cal ka BP. In particular, recent developments of accelerator mass spectrometry (AMS)-related techniques have opened a variety of applications. A Tandetron AMS system (Model 4130-AMS, HVE, B.V., the Netherlands) introduced in 1996/97 at Nagoya University, still has excellent performance, and this device has been used frequently for 14C dating of late Quaternary samples. Here, we describe briefly the AMS 14C-measurement system of Nagoya University and then focus on the following four applications for Japanese Holocene samples: i) 14C dating and dendrochronological analysis of wood samples excavated from archeological sites; ii) 14C dating analysis of individual annual rings of a huge tree to compare the 14C age variations with the IntCal13 dataset; iii) research on the carbon reservoir effects of marine samples around the Japanese Archipelago; iv) potential application of a new 14C landmark for precise calendar age estimation of tree rings.

Age of the Younger Laxá Lava and Lake Mývatn, Northern Iceland, Determined by AMS Radiocarbon Dating

Lake Mývatn and several smaller lakes in northern Iceland were formed by the large Holocene lava flow of the Younger Laxá Lava (YLL). The age of the YLL was estimated by tephrochronology at 1800–2300 BP (Thorarinsson 1951). Conventional radiocarbon dating of charred vegetation beneath the YLL (Thorarinsson 1964) yielded uncalibrated ages of 1940 ± 27014C yr BP (Yale), 2110 ± 14014C yr BP (Copenhagen), and 1990 ± 5014C yr BP (Winnipeg). Ongoing palcolimnological research at Lake Mývatn requires a more precise age estimation of the YLL. Charcoal samples from beneath the YLL were collected at Presthvammur in 2007 and analyzed by accelerator mass spectrometry (AMS)14C measurements. The reliability of the conventional14C ages of the samples Yale, Copenhagen, and Winnipeg was re-evaluated, applying criteria from Pettit et al. (2003) and Graf (2009). The result of AMS14C measurement (2170 ± 38 cal yr BP) underpins the local tephrochronology and provides a reliable age of the YLL and Lake Mývatn.

High-precision Radiocarbon Dating with Accelerator Mass Spectrometry and Calibration of Radiocarbon Ages

High-resolution as well as high-precision age estimation is particularly important for Quaternary research to realize its main aim of better understanding of global environmental changes of the past and realistic prediction of the changes in the near future. Among several dating methods that are applicable to Quaternary samples, radiocarbon (14C) dating has been commonly used since its development in late 1940s.A new 14C detection technique, accelerator mass spectrometry (AMS), has been developed since 1977. The method directly detects and counts 14C atoms, instead of counting β-ray emitted in the decay of 14C, and therefore requires only a few mg of carbon for 14C measurements. Nowadays, AMS 14C dating is widely used and more than sixty AMS 14C facilities are in operation in the world. In Japan, eight facilities for AMS 14C dating have been in use since 2004.As one of the eight AMS 14C measurement systems in Japan, the Nagoya University AMS group has started routine 14C measurements with the firstly introduced Tandetron AMS system since 1983 and also with the secondly established Tandetron AMS since 1999. The second system has an excellent performance of the standard deviation (one sigma) of the 14C/12C ratios of around ±0.2% to ±0.4% (±17-±30 14C yrs) and that of the corresponding 13C/12C ratios of ±0.03% to ±0.07%, as are tested for HOxII targets. By using this AMS system, we are now trying to provide accurate ages to the Quaternary events. Briefly discussed in this article are, (1) a consistency test of the established IntCal98 and IntCal04 14C data sets with the 14C-concentration records in Japanese tree rings ; (2) programs of high accuracy and precision age estimation by 14C wiggle matching techniques for wood samples ; (3) investigations of 14C reservoir effect for marine samples from the Japanese Archipelago.

AMS 14C Dating of Iron Artifacts: Development and Application

We have developed a prototype carbon extraction system for accelerator mass spectrometry (AMS) radiocarbon dating of archaeological iron remains by combusting them with a RF induction furnace. We have also successfully tested and used a method of carbon extraction from iron using a CuCl2 solution. Modifications to our carbon extraction systems and methods provide us acceptable performances; carbon yield is normally around 80% and the 14C background level is as low as 42–48 ka BP in 14C apparent age. We have also conducted an iron refining experiment to examine the sources for carbon 14C age derived from iron, using established AMS 14C dating and carbon extraction systems. Our refining experiment was conducted on iron slag, which are by-products formed during iron smelting methods in the 7th century AD, and using modern charcoal as fuel. The aim of the experiment was to determine whether original carbon characteristics in the original iron materials would be preserved, or if the carbon signature would be replaced to some degree by the modern charcoal. AMS 14C measurements on the refined iron yielded 14C ages equivalent to those of the modern charcoal fuel. The result indicates that the original carbon signatures in the iron slag from 7th century production was replaced completely by modern carbon used in our experiment. The experiment confirms the assumption that 14C ages on iron products are associated with the fuel source of the iron smelting or refining process. We also report on the dating of iron slag materials excavated from the Gennaitouge iron smelting site, where 14C dates were consistent with the age of the site estimated by archaeological evidence.

Late-Glacial and Early Holocene Environmental and Climatic Change at Lake Tambichozero, Southeastern Russian Karelia

High-resolution lithostratigraphy, mineral magnetic, carbon, pollen, and macrofossil analyses, and accelerator mass spectrometry 14C measurements were performed in the study of a sediment sequence from Lake Tambichozero, southeastern Russian Karelia, to reconstruct late-glacial and early Holocene aquatic and terrestrial environmental changes. The lake formed ca. 14,000 cal yr B.P. and the area around the lake was subsequently colonized by arctic plants, forming patches of pioneer communities surrounded by areas of exposed soil. A minor rise in lake productivity and the immigration of Betula pubescens occurred ca. 11,500 cal yr B.P. The rise in summer temperatures probably led to increased melting of remnant ice and enhanced erosion. The distinct increase in lake productivity and the development of open Betula-Populus forests, which are reconstructed based on plant macrofossil remains, indicate stable soils from 10,600 cal yr B.P. onward. Pinus and Picea probably became established ca. 9900 cal yr B.P.

Preparation of Graphite Targets in the Gliwice Radiocarbon Laboratory for AMS14C Dating

A line for preparation of graphite targets for accelerator mass spectrometry (AMS) radiocarbon dating has been built in the Gliwice14C Laboratory. The AMS14C measurements of our targets are performed in the Leibniz-Labor für Altersbestimmung, Kiel, Germany. The quality of our line has been tested in two series of AMS14C measurements of background and Ox-II standard samples and by measurements of the amount of CO2released during combustion of sample-free quartz tubes. Most background contamination in the first series was introduced during combustion, which has been greatly reduced by baking quartz tubes vacuum-sealed with CuO and Ag. The residual contamination (ca. 1.5 μg C) seems to come mostly from the quartz tubes themselves. At present, most of the contamination of the background is introduced during graphitization. The reproducibility of background preparations is satisfactory, especially for samples larger than 1.5 mg, when it is better than ± 0.09 pMC. Despite still significant contamination with low-14C carbon during the graphitization process (corresponding to 1.2 ± 0.2% of14C-free carbon), the good reproducibility of the results allows us to use our line in routine14C dating.

Deep-sea sedimentary record of the late Wisconsin cataclysmic floods from the Columbia River

Research Article| May 01, 1999 Deep-sea sedimentary record of the late Wisconsin cataclysmic floods from the Columbia River Charlotte A. Brunner; Charlotte A. Brunner 1Department of Marine Science, University of Southern Mississippi, Stennis Space Center, Mississippi 39529, USA Search for other works by this author on: GSW Google Scholar William R. Normark; William R. Normark 2U.S. Geological Survey, MS 999, 345 Middlefield Road, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Gian G. Zuffa; Gian G. Zuffa 3Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Via Zamboni 67, 40127 Bologna, Italy Search for other works by this author on: GSW Google Scholar Francesca Serra Francesca Serra 3Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Via Zamboni 67, 40127 Bologna, Italy Search for other works by this author on: GSW Google Scholar Author and Article Information Charlotte A. Brunner 1Department of Marine Science, University of Southern Mississippi, Stennis Space Center, Mississippi 39529, USA William R. Normark 2U.S. Geological Survey, MS 999, 345 Middlefield Road, Menlo Park, California 94025, USA Gian G. Zuffa 3Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Via Zamboni 67, 40127 Bologna, Italy Francesca Serra 3Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Bologna, Via Zamboni 67, 40127 Bologna, Italy Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1999) 27 (5): 463–466. https://doi.org/10.1130/0091-7613(1999)027<0463:DSSROT>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Charlotte A. Brunner, William R. Normark, Gian G. Zuffa, Francesca Serra; Deep-sea sedimentary record of the late Wisconsin cataclysmic floods from the Columbia River. Geology 1999;; 27 (5): 463–466. doi: https://doi.org/10.1130/0091-7613(1999)027<0463:DSSROT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract New results from Ocean Drilling Program Site 1037 and U.S. Geological Survey high-resolution seismic-reflection profiles confirm the great thickness, fast deposition rate, distant source, and convolute path of turbidites that fill the Escanaba Trough, the rift valley of the southernmost segment of the Gorda Ridge. Accelerator mass spectrometry 14C measurements provide the first direct dating of the Escanaba Trough turbidites, demonstrating an average deposition rate faster than 10 m/k.y. between 32 and 11 ka and as fast as 15 m/k.y. during the oxygen isotope stage 2 lowstand. In the upper 60 m of sediment, the petrology of turbidite sand beds, which are as much as 12 m thick, show that the dominant source for the turbidites is from the Columbia River, which is more than 800 km to the north, rather than from the much closer rivers of northern California. New high-resolution seismic-reflection profiles show that, except for areas of very recent volcanism, the entire Escanaba Trough below 3200 m water depth is floored by the turbidite sequence that was cored in the upper 60 m at Site 1037B. The ages of the upper 120 m of turbidites correspond with the ages of channeled scabland deposits associated with latest Quaternary jokulhlaups from glacial Lake Missoula. The age and source characteristics suggest that these megaturbidite beds in Escanaba Trough are most likely deposits formed by hyperpycnally generated turbidity currents as the largest of the Lake Missoula floods entered the sea. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Isotope stratigraphy, sedimentation rates, deep circulation, and carbonate events in the Labrador Sea during the last ~ 200 ka

High-resolution stable-isotope and accelerator mass spectrometry 14C measurements in 25 box and piston cores from the Labrador Sea allow the reconstruction of major paleoceanographical changes during the last ~ 200 ka in this basin and also document the links between the interior of the Laurentide Ice Sheet and the North Atlantic Ocean during this interval. Two deep circulation regimes are indicated by contrasting sedimentation rates on the slopes: (i) the modern situation is characterized by a gyre of the North Atlantic Deep Water (NADW) components into the basin, which is responsible for the high-energy Western Boundary Undercurrent; this regime also prevailed during the former "true" interglacials and possibly during shorter "warm" intervals (e.g., Bølling-Allerød); (ii) a more frequent NADW-free situation during glacial and interstadial intervals is marked by the presence of a vertically homogeneous water mass in the basin. Sedimentological records also indicate that carbonate events (i.e., pulses of detrital Paleozoic carbonates from Hudson Strait) and Heinrich events (sharp increases in ice-rafted lithic fragments), which are observed during the last two glaciations, are due to two distinct mechanisms. We hypothesize that detrital-carbonate events are linked to the triggering of turbidity currents in the western Labrador Sea by surges of the ice margin off Hudson Strait, and that the North Atlantic Mid-Ocean Channel, and possibly the Charlie Gibbs Fracture Zone, played a role in the spreading of these carbonates into the North Atlantic. Rapid calving would have been responsible for the intense ice rafting responsible for the Heinrich events stricto sensu. During such intervals, low productivity in surface waters is inferred from light carbon events and low concentrations in primary productivity indicators.