Radiocarbon Dating of Bones at the LARA Laboratory in Bern, Switzerland

Radiocarbon ◽  
2016 ◽  
Vol 59 (3) ◽  
pp. 831-842 ◽  
Author(s):  
Sönke Szidat ◽  
Edith Vogel ◽  
Regula Gubler ◽  
Sandra Lösch
Keyword(s):  
Acid Treatment ◽  
Radiocarbon Dating ◽  
Sample Pretreatment ◽  
Bulk Sediment ◽  
Acid Base ◽  
The Holocene ◽  
Plant Remains ◽  
University Of Bern ◽  
The University

AbstractThe Laboratory for the Analysis of Radiocarbon with AMS (LARA) was established at the University of Bern in 2013. Since then, the quality of sample preparation and radiocarbon measurement procedures have been validated for different materials such as plant remains, macrofossils, bulk sediment, charcoals, and wood. This article presents the optimization of sample pretreatment of bones based on protocols described in the literature. The extraction of collagen was performed with an acid-base-acid treatment, gelatinization, coarse filtration, lyophilization, and graphitization. Dating results were validated as satisfactory for the Holocene by investigation of 36 individual samples previously dated by other 14C laboratories including VIRI/SIRI materials and from well-known archaeological contexts. An additional blank contribution for bone treatment was determined by comparison with the preparation of other sample materials. The cases of two outliers from the Holocene were studied in detail.

SUITABILITY OF ACID-SOLUBLE AND ACID-INSOLUBLE LEATHER FRACTIONS IN RADIOCARBON DATING

Radiocarbon ◽  
2020 ◽  
pp. 1-8
Author(s):  
Alyssa M Tate ◽  
Brittany Hundman ◽  
Jonathan Heile
Keyword(s):  
Radiocarbon Dating ◽  
Insoluble Fraction ◽  
Economic Life ◽  
Chemical Pretreatment ◽  
Acid Base ◽  
The Past ◽  
Acid Soluble Collagen ◽  
Method Of Production ◽  
Insight Into

ABSTRACT Leather has been produced by a variety of methods throughout human history, providing researchers unique insight into multiple facets of social and economic life in the past. Archaeologically recovered leather is often fragile and poorly preserved, leading to the use of various conservation and restoration efforts that may include the application of fats, oils, or waxes. Such additives introduce exogenous carbon to the leather, contaminating the specimen. These contaminants, in addition to those accumulated during interment, must be removed through chemical pretreatment prior to radiocarbon (14C) dating to ensure accurate dating. DirectAMS utilizes organic solvents, acid-base-acid (ABA) and gelatinization for all leather samples. Collagen yield from leather samples is variable due to the method of production and the quality of preservation. However, evaluating the acid-soluble collagen fraction, when available, provides the most accurate 14C dates for leather samples. In instances where gelatinization does not yield sufficient material, the resulting acid-insoluble fraction may be dated. Here we examine the effectiveness of the combined organic solvent and ABA pretreatment with gelatinization for leather samples, as well as the suitability of the acid-insoluble fraction for 14C dating.

scholarly journals The BernClim plant phenological data set from the canton of Bern (Switzerland) 1970–2018

2019 ◽  
Vol 11 (4) ◽  
pp. 1645-1654 ◽  
Author(s):  
This Rutishauser ◽  
François Jeanneret ◽  
Robert Brügger ◽  
Yuri Brugnara ◽  
Christian Röthlisberger ◽  
...  
Keyword(s):  
Growing Season ◽  
Data Set ◽  
Urban And Regional Planning ◽  
Phenological Data ◽  
Observation Network ◽  
Good Internal Consistency ◽  
Change Impact ◽  
University Of Bern ◽  
The University

Abstract. In 1970, the Institute of Geography of the University of Bern initiated the phenological observation network BernClim. Seasonality information from plants, fog and snow was originally available for applications in urban and regional planning and agricultural and touristic suitability and is now a valuable data set for climate change impact studies. Covering the growing season, volunteer observers record the dates of key development stages of hazel (Corylus avellana), dandelion (Taraxacum officinale), apple tree (Pyrus malus) and beech (Fagus sylvatica). All observations consist of detailed site information, including location, altitude, exposition (aspect) and inclination, that makes BernClim unique in its richness in detail on decadal timescales. Quality control (QC) by experts and statistical analyses of the data have been performed to flag impossible dates, dates outside the biologically plausible range, repeated dates in the same year, stretches of consecutive identical dates and statistically inconsistent dates (outliers in time or in space). Here, we report BernClim data of 7414 plant phenological observations from 1970 to 2018 from 1304 sites at 110 stations, the QC procedure and selected applications (Rutishauser et al., 2019: https://doi.org/10.1594/PANGAEA.900102). The QC points to very good internal consistency (only 0.2 % were flagged as internally inconsistent) and likely high quality of the data. BernClim data indicate a trend towards an extended growing season. They also track the regime shift in the late 1980s well to pronounced earlier dates like numerous other phenological records across the Northern Hemisphere.

scholarly journals AMS Radiocarbon Dating of Paleolithic-Aged Charcoal from Europe and the Mediterranean Rim Using ABOx-SC

Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 839-846 ◽  
Author(s):  
F Brock ◽  
T F G Higham
Keyword(s):  
South Africa ◽  
Failure Rate ◽  
Radiocarbon Dating ◽  
Sample Pretreatment ◽  
Combustion Method ◽  
High Failure Rate ◽  
Acid Base ◽  
Ams Radiocarbon Dating ◽  
The Mediterranean

Radiocarbon dating of charcoal >25–30 kyr can be problematic due to contamination from exogeneous carbon and the variable effectiveness of 14C pretreatments to remove it. Bird et al. (1999) developed the ABOx-SC (acid-base-oxidation-stepped combustion) method for removing contaminants from older charcoal samples, which involves a harsher treatment than traditional acid-base-acid (ABA) pretreatments. This method has been shown to considerably improve the reliability of dating old charcoal from sites in Australia, South Africa, Brazil, and Malaysia (Bird et al. 1999, 2003; Turney et al. 2001; Santos et al. 2003; Higham et al. 2009a). Here, we apply the technique to material from 5 Paleolithic sites from Europe and the Mediterranean Rim. For 2 of the sites (Kebara Cave, Israel and Taramsa Hill, Egypt), the ABOx-SC and ABA methods produced similar dates. However, in the case of 1 site, the Grotta di Fumane in Italy, ABOx-SC pretreatment produced significantly older results from those of ABA methods, requiring substantial reinterpretation of the archaeological sequence of the site. The rigorous nature of the technique resulted in a high failure rate for sample pretreatment, and insufficient material survived the pretreatment for dating from Grotte des Pigeons, Morocco or Gorham's Cave, Gibraltar.

scholarly journals 14C Analysis and Sample Preparation at the New Bern Laboratory for the Analysis of Radiocarbon with AMS (LARA)

Radiocarbon ◽  
2014 ◽  
Vol 56 (02) ◽  
pp. 561-566 ◽  
Author(s):  
Sönke Szidat ◽  
Gary A Salazar ◽  
Edith Vogel ◽  
Michael Battaglia ◽  
Lukas Wacker ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Ion Source ◽  
Carbon Dating ◽  
Climate Research ◽  
Accelerator Mass Spectrometer ◽  
History Of ◽  
Set Up ◽  
University Of Bern ◽  
The University

The University of Bern has set up the new Laboratory for the Analysis of Radiocarbon with AMS (LARA) equipped with an accelerator mass spectrometer (AMS) MICADAS (MIni CArbon Dating System) to continue its long history of14C analysis based on conventional counting. The new laboratory is designated to provide routine14C dating for archaeology, climate research, and other disciplines at the University of Bern and to develop new analytical systems coupled to the gas ion source for14C analysis of specific compounds or compound classes with specific physical properties. Measurements of reference standards and wood samples dated by dendrochronology demonstrate the quality of the14C analyses performed at the new laboratory.

scholarly journals 14C AMS Dating of Icelandic Lake Sediments

Radiocarbon ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 865-872 ◽  
Author(s):  
Árný E. Sveinbjörnsdóttir ◽  
Jan Heinemeier ◽  
Peter Kristensen ◽  
Niels Rud ◽  
Áslaug Geirsdóttir ◽  
...  
Keyword(s):  
Sample Pretreatment ◽  
Bulk Sediment ◽  
Organic Fraction ◽  
Sediment Samples ◽  
Age Diversity ◽  
Plant Remains ◽  
Ams Dating ◽  
Lowermost Part ◽  
Reservoir Age ◽  
Depth Curve

We report an age-depth profile for the sediments of the Lake Hesrvatn, southern Iceland, based on 14C analyses of the organic fraction of bulk sediment samples, molluscs and foraminifera. Our age-depth curve is supported by the occurrence of the well-dated Vedde ash in the lowermost part of the sediments. Comparison of foraminifera dates with the age of the Vedde ash indicates a reservoir age of ca. 400 yr. The results suggest that the sediments at Hestvatn accumulated in a marine environment until ca. 8700 bp and thereafter in freshwater.Owing to the lack of terrestrial macrofossils and the low concentration of molluscs and foraminifera, we were forced to attempt to date most of the core with the organic fraction of the bulk sediment samples. We found, however, that this fraction is not homogeneous in density or 14C age. We believe that during sample pretreatment we managed to isolate a light organic fraction, which closely represents the true age of the sediment, whereas the denser fraction yields ages that are too high. This age diversity may to some extent be explained by the large drainage area of the lake, from which plant remains of different ages may have been washed into the lake.

scholarly journals 14C Analysis and Sample Preparation at the New Bern Laboratory for the Analysis of Radiocarbon with AMS (LARA)

Radiocarbon ◽  
2014 ◽  
Vol 56 (2) ◽  
pp. 561-566 ◽  
Author(s):  
Sönke Szidat ◽  
Gary A Salazar ◽  
Edith Vogel ◽  
Michael Battaglia ◽  
Lukas Wacker ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Ion Source ◽  
Carbon Dating ◽  
Climate Research ◽  
Accelerator Mass Spectrometer ◽  
History Of ◽  
Set Up ◽  
University Of Bern ◽  
The University

The University of Bern has set up the new Laboratory for the Analysis of Radiocarbon with AMS (LARA) equipped with an accelerator mass spectrometer (AMS) MICADAS (MIni CArbon Dating System) to continue its long history of 14C analysis based on conventional counting. The new laboratory is designated to provide routine 14C dating for archaeology, climate research, and other disciplines at the University of Bern and to develop new analytical systems coupled to the gas ion source for 14C analysis of specific compounds or compound classes with specific physical properties. Measurements of reference standards and wood samples dated by dendrochronology demonstrate the quality of the 14C analyses performed at the new laboratory.

scholarly journals Atmospheric CO<sub>2</sub>, δ(O<sub>2</sub>/N<sub>2</sub>) and δ<sup>13</sup>CO<sub>2</sub> measurements at Jungfraujoch, Switzerland: results from a flask sampling intercomparison program

2013 ◽  
Vol 6 (7) ◽  
pp. 1805-1815 ◽  
Author(s):  
I. T. van der Laan-Luijkx ◽  
S. van der Laan ◽  
C. Uglietti ◽  
M. F. Schibig ◽  
R. E. M. Neubert ◽  
...  
Keyword(s):  
Research Station ◽  
Average Difference ◽  
Max Planck ◽  
Atmospheric Measurements ◽  
Weekly Basis ◽  
The World ◽  
Intercomparison Exercises ◽  
University Of Bern ◽  
The University

Abstract. We present results from an intercomparison program of CO2, δ(O2/N2) and δ13CO2 measurements from atmospheric flask samples. Flask samples are collected on a bi-weekly basis at the High Altitude Research Station Jungfraujoch in Switzerland for three European laboratories: the University of Bern, Switzerland, the University of Groningen, the Netherlands and the Max Planck Institute for Biogeochemistry in Jena, Germany. Almost 4 years of measurements of CO2, δ(O2/N2) and δ13CO2 are compared in this paper to assess the measurement compatibility of the three laboratories. While the average difference for the CO2 measurements between the laboratories in Bern and Jena meets the required compatibility goal as defined by the World Meteorological Organization, the standard deviation of the average differences between all laboratories is not within the required goal. However, the obtained annual trend and seasonalities are the same within their estimated uncertainties. For δ(O2/N2) significant differences are observed between the three laboratories. The comparison for δ13CO2 yields the least compatible results and the required goals are not met between the three laboratories. Our study shows the importance of regular intercomparison exercises to identify potential biases between laboratories and the need to improve the quality of atmospheric measurements.

scholarly journals 14C Research at the Laboratory for the Analysis of Radiocarbon with AMS (LARA), University of Bern

2020 ◽  
Vol 74 (12) ◽  
pp. 1010-1014
Author(s):  
Sönke Szidat
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Quality Improvement ◽  
Particulate Matter ◽  
Radiocarbon Dating ◽  
Radioactive Carbon ◽  
Fossil Carbon ◽  
Air Quality Improvement ◽  
University Of Bern ◽  
The University

The Laboratory for the Analysis of Radiocarbon with AMS (LARA) at the University of Bern measures the radioactive carbon isotope 14C with accelerator mass spectrometry (AMS) in different applications. Besides radiocarbon dating of environmental and archaeological samples, the LARA focuses on source apportionment of air-borne particulate matter (i.e. aerosols) as well as greenhouse gases such as carbon dioxide and methane. This approach allows the identification and quantification of fossil carbon emissions in these air components, which is relevant for measures of air-quality improvement. The LARA furthermore develops instrumental setups for and at the AMS in order to analyze 14C samples in μg-amounts with low contamination and high throughput, preferably using online-hyphenated systems.

scholarly journals Atmospheric CO<sub>2</sub>, δ(O<sub>2</sub>/N<sub>2</sub>) and δ<sup>13</sup>CO<sub>2</sub> measurements at Jungfraujoch, Switzerland: results from a flask sampling intercomparison program

2012 ◽  
Vol 5 (5) ◽  
pp. 7293-7322 ◽  
Author(s):  
I. T. van der Laan-Luijkx ◽  
S. van der Laan ◽  
C. Uglietti ◽  
M. F. Schibig ◽  
R. E. M. Neubert ◽  
...  
Keyword(s):  
Research Station ◽  
Average Difference ◽  
Max Planck ◽  
Atmospheric Measurements ◽  
Weekly Basis ◽  
The World ◽  
Intercomparison Exercises ◽  
University Of Bern ◽  
The University

Abstract. We present results from an intercomparison program of CO2, δ(O2/N2) and δ13CO2 measurements from atmospheric flask samples. Flask samples are collected on a bi-weekly basis at the High Altitude Research Station Jungfraujoch in Switzerland for three European laboratories: the University of Bern, Switzerland, the University of Groningen, the Netherlands and the Max Planck Institute for Biogeochemistry in Jena, Germany. Almost 4 yr of measurements of CO2, δ(O2/N2) and δ13CO2 are compared in this paper to assess the measurement compatibility of the three laboratories. While the average difference for the CO2 measurements between the laboratories in Bern and Jena meets the required compatibility goal as defined by the World Meteorological Organisation, the standard deviation of the average differences between all laboratories is not within the required goal. However, the obtained annual trend and seasonalities are the same within their estimated uncertainties. For δ(O2/N2) significant differences are observed between the three laboratories. The comparison for δ13CO2 yields the least compatible results and the required goals are not met between the three laboratories. Our study shows the importance of regular intercomparison exercises to identify potential biases between laboratories and the need to improve the quality of atmospheric measurements.

Epistemic and relational conflicts in sharing identical vs. complementary information during cooperative learning

2002 ◽  
Vol 61 (3) ◽  
pp. 139-151 ◽  
Author(s):  
Céline Darnon ◽  
Céline Buchs ◽  
Fabrizio Butera
Keyword(s):  
Cooperative Learning ◽  
Social Comparison ◽  
Positive Relationship ◽  
Learning Task ◽  
Control Group ◽  
Complementary Information ◽  
Relational Conflict ◽  
The Social ◽  
The University

When interacting on a learning task, which is typical of several academic situations, individuals may experience two different motives: Understanding the problem, or showing their competences. When a conflict (confrontation of divergent propositions) emerges from this interaction, it can be solved either in an epistemic way (focused on the task) or in a relational way (focused on the social comparison of competences). The latter is believed to be detrimental for learning. Moreover, research on cooperative learning shows that when they share identical information, partners are led to compare to each other, and are less encouraged to cooperate than when they share complementary information. An epistemic vs. relational conflict vs. no conflict was provoked in dyads composed by a participant and a confederate, working either on identical or on complementary information (N = 122). Results showed that, if relational and epistemic conflicts both entailed more perceived interactions and divergence than the control group, only relational conflict entailed more perceived comparison activities and a less positive relationship than the control group. Epistemic conflict resulted in a more positive perceived relationship than the control group. As far as performance is concerned, relational conflict led to a worse learning than epistemic conflict, and - after a delay - than the control group. An interaction between the two variables on delayed performance showed that epistemic and relational conflicts were different only when working with complementary information. This study shows the importance of the quality of relationship when sharing information during cooperative learning, a crucial factor to be taken into account when planning educational settings at the university.

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