A J T Jull
Biographic Data
| ID | 248762 |
|---|---|
| NAME | A J T Jull |
| GIVEN NAMES | A J T |
| FAMILY NAME | Jull |
| SIGNATURE | JULL A J T |
| AFFILIATIONS | University of Arizona |
| ORCID | 0000-0002-4079-4947 |
| VERIFIED | Yes |
| TOTAL WORKS | 133 |
| TOTAL CITATIONS | 747 |
| AUTHOR COUNT | 133 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1983 |
| LATEST PUBLICATION YEAR | 2025 |
| H-INDEX | 14 |
Radiocarbon dating of the Church of St. Margaret of Antioch in Kopčany (Slovakia)
An international consortium of radiocarbon laboratories has established the origin of the Church of St. Margaret of Antioch in Kopčany (Slovakia), because its age was not well known from previous investigations. In total, 13 samples of charcoal, wood, mortar, and plaster were analyzed. The 14 C results obtained from the different laboratories, as well as between the different sample types, were in good agreement. Resulting the final 14 C calibrat…
C age of recent natural earthworm biospheroids—implications for paleosol dating
Earthworm biospheroids are a useful alternative to radiocarbon ( 14 C) soil dating. In this study, we undertook a series of measurements to test the 14 C dating potential/performance of recent earthworm biospheroid granules. A novel sample preparation protocol for 14 C in biospheroids was developed and elaborated at Atomki (Institute for Nuclear Research) and tested on IAEA reference materials. 24 natural biospheroid samples were extracted from f…
The last 40,000 years of a floodplain area (Tisza, Hungary) comparative case study of 14C and OSL methods
To investigate the environmental history of the Tisza River (Hungary), we applied 14 C and OSL dating methods for five parallel, neighboring cores from the flood plain area (Jászság Basin). Four major sedimentary layers were identified: meadow soil on the top (S1); silty-clay (S2); clayey-silt (S3) section; and fine sand (S4). 14 C and OSL data were integrated into a synthetic age-depth model using the BACON software package. Formation of the S1 …
Novel dissolved organic 14C analyses method applied in a case study at a Lilw waste repository
A routine chemical procedure was developed at the Ede Hertelendi Laboratory of Environmental Studies (HEKAL), in Debrecen which can measure the dissolved organic radiocarbon content of groundwater as well as the inorganic and total fraction. The typical background of this non-purgeable dissolved organic radiocarbon preparation is 0.73 ± 0.14 percent modern carbon (pMC), using a carbon contamination correction on fossil dissolved material (potassi…
Performance and Inter-Comparison Tests of the Micadas at the Radiocarbon Laboratory of Lanzhou University, China
Since 2018, the radiocarbon laboratory of Lanzhou University has been equipped with a compact accelerator mass spectrometer—a 200-KV mini carbon dating system (MICADAS), together with an auto graphitization equipment (AGE III). The laboratory has for a long time prepared graphite targets for 14 C dating of plant fossils, charcoal, bones, and bulk organic matter. Herein, we give an overview of the operating status and performance of the dating fac…
The Potential of Biogenic Fraction Analysis by Radiocarbon in Food, Drug, and Cosmetic Products
Biobased content analysis is a well-established, analytically independent, standardized method to determine the biobased content of fuels and plastics, based on differences of the specific radiocarbon ( 14 C) activity of fossil and recent biogenic compounds. This biogenic content analysis can be useful for the producers as a quality assurance tool, for the customers as feedback about the truly biobased products and for the control organizations a…
Intercomparison Exercise on Fuel Samples for Determination of Biocontent Ratio by 14 C Accelerator Mass Spectrometry
The method of determining the biobased carbon content in liquid fuel samples is standardized, but different laboratories use different protocols during sample preparation and perform the measurements using different machines. The accelerator mass spectrometry (AMS) laboratories use different combustion, preparation, and graphitization methods for the graphite production for the spectrometric measurements. As a result, the intercomparison between …
Obituary
Douglas J. Donahue was one of the pioneers of accelerator mass spectrometry at the University of Arizona. He passed away just shy of his 96th birthday in September 2020, exactly six months after Dee, his beloved wife of 72 years. We all have fond memories of the time we spent working with Doug, and he left his mark on us all. We'd like to share some of those memories, in a slightly scientific context. Doug was born in 1924, on Douglas St. in Wich…
The Iaea Forensics Program
In the frame of the IAEA-CRP (Coordinated Research Projects): Enhancing Nuclear Analytical Techniques to Meet the Needs of Forensic Sciences , an intercomparison exercise was organized between three AMS laboratories. Aim of the program is to promote the use of nuclear and accelerator-based techniques in routine forensics practice. In this view, one of the key points is the assessment of the precision and accuracy levels achievable on material of …
Scaling the 14 C-Excursion Signal in Multiple Tree-Ring Series With Dynamic Time Warping
A signal of rapid changes in 14 C production is logged in annual series of 14 C derived from tree rings, which can be associated with diverse effects of cosmic-ray fluxes, including solar burst and supernova events. These 14 C signatures may vary in time and space. The intensity and structure of the 14 C signal is multifaced, which complicates understanding of the forcing and attribution of the underlying astrophysical events. It was suggested th…
Chronology of the Golden Horde in Kazakhstan
We present accelerator mass spectrometry radiocarbon (AMS 14 C) dating results of the “Jochi Khan Mausoleum”—the proposed burial place of the oldest son of Gengghis Khan in Ulytau, Kazakhstan. The Ulytau region retains 34 burial complexes of Islamic tradition associated with the Golden Horde history (1221–1438 CE). However, there is no calendar-dated chronology of the medieval mausoleums in this region, which complicates their historical interpre…
Soil Organic Carbon Dating of Paleosoils of Alluvial Fans in a Blown Sand Area (Nyírség, Hungary)
The most widely used dating techniques in quaternary research are the radiocarbon ( 14 C) and optically stimulated luminescence (OSL) dating methods. In some environments, the investigated sediments do not contain enough material for 14 C dating. In these cases, 14 C dating of bulk sediment may be used as a last resort. The major aim of the present study was to determine the reliability and limitations of the different fractions of the soil organ…
Radiocarbon Dating of St. George’s Rotunda in Nitrianska Blatnica (Slovakia)
An international consortium of radiocarbon ( 14 C) laboratories was established to date the origin of the St. George’s Rotunda in Nitrianska Blatnica (Slovakia), because its age was not well established in previous investigations. Altogether, 20 samples of wood, charcoal, mortar and plaster were analyzed. The 14 C results obtained from the different laboratories as well as between the different sample types were in good agreement, resulting in a …
Gas Ion Source Performance of the Environmicadas at Hekal Laboratory, Debrecen, Hungary
A coupled accelerator mass spectrometer–gas interface system has been successfully operating at the Hertelendi Laboratory of Environmental Studies, Debrecen, Hungary, since 2013. Over the last 6 years more than 500 gas targets were measured below 100 μg carbon content for carbon isotopic composition. The system was tested with blanks, OxII, IAEA-C1, IAEA-C2, and IAEA-C7 standards. The performance of our instrumentation shows good agreement with o…
C Intercomparison Exercise on Bones and Ivory Samples
The application of accelerator mass spectrometry radiocarbon (AMS 14 C) dating in forensics is made possible by the use of the large excursion of the 14 C concentration in the post-WWII terrestrial atmosphere due to nuclear testing as a reference curve for data calibration. By this approach high-precision analyses are possible on samples younger than ∼70 years. Nevertheless, the routine, widespread application of the method in the practice of for…
Radiocarbon Ages of Suyanggae Paleolithic Sites in Danyang, Korea
The Suyanggae archeological complex is located in Aegok-li, Danyang County, Chungbuk Province, Korea (128°20'00"E, 365 ̊7'15"N, elevation 132 m). We investigated two Suyanggae Paleolithic localities (1 and 6). A total of 31 samples (18 localities) were analyzed for radiocarbon ( 14 C) ages in three paleolithic cultural horizons of Suyanggae Locality 6 (SYG-6). The purpose of this paper is to report all dating results of SYG-6. It was found that r…
An Intercomparison Project on 14 C From Single-Year Tree Rings
A laboratory intercomparison project was carried out on 20 annually resolved late-wood samples from the Danish oak record. The project included the following three laboratories: (1) the University of Arizona AMS Laboratory, University of Arizona, USA (AA); (2) HEKAL AMS Laboratory, MTA Atomki, Hungary (DeA); and (3) Aarhus AMS Centre (AARAMS), Aarhus University, Denmark (AAR). The large majority of individual data points (96%) lie within ±2σ of t…
Anthropogenic 129I in the South China Sea and coastal waters around Taiwan
In this article, we present a study of seawater 129I/127I time-series data from several coastal sites in Taiwan, including Yehliu Geopark (north–northeast coast), Kaohsiung (southwest coast), and Zhuwei Fishing Village (northwest coast). The objective of this study was to document how 129I/127I responds to known seasonal variations in the surface ocean currents that carry 129I to each of these sites. The responses were shown to be quite distinct.…
Ams 14 C Dating of the Mayan Codex of Mexico Revisited
The Mayan Codex of Mexico (MCM), the only Mayan codex found in the 20th century, was unveiled in 1971 during the Ancient Maya Calligraphy exhibition at Club Grolier. The codex comprises 10 pages of bark paper in accordion format, coated with a layer of plaster on both sides. It illustrates the synodic cycles of Venus, with its four phases. Since its discovery, the MCM has been subject to controversy and discussions about its authenticity. In 2016…
The Best Possible Time Resolution
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Spatial Distribution of 14 C in Tree Leaves from Bali, Indonesia
The increase of fossil-fuel-derived CO 2 in the atmosphere has led to the dilution of the atmospheric radiocarbon concentration, but due to the costly instrumentation, the continuous atmospheric 14 C/ 12 C data is incomplete in developing countries, such as in Indonesia. These data give useful information about the level of local and regional fossil emissions. In this study, 14 C AMS measurements of local vegetation and woody plant species sample…
Can the 14 C Production in 1055 Ce Be Affected by Sn1054
Annually resolved radiocarbon ( 14 C) measurements on tree rings led to the discovery of abrupt variations in 14 C production attributed to large solar flares. We present new results of annual and subannual 14 C fluctuations in tree rings from a middle-latitude sequoia (California) and a high-latitude pine (Finland), analyzed for the period 1030–1080 CE, to trace a possible impact of the Crab supernova explosion, occurring during the Oort minimum…
Signatures of global climatic events and forcing factors for the last two millennia from the active mudflats of Rohisa, southern Saurashtra, Gujarat, western India
Assessment and Development of Bone Preparation for Radiocarbon Dating at Hekal
Bone is one of the most complex sample materials used for radiocarbon ( 14 C) dating. The installation of the EnvironMICADAS AMS at HEKAL (department of ICER) in 2011 required the adoption of new sample preparation techniques for small bone samples. Since then, hundreds of procedural background and known-age bones have been processed using our modified Longin method (MLM) and dated along with unknown samples. Their results are used in this study …
The Best possible Time resolution
Today, accelerator mass spectrometry (AMS) technology enables us to carry out very precise measurements of radiocarbon ( 14 C). Unfortunately, due to fluctuations in the 14 C calibration curve, the resulting calibrated time intervals vary from decades up to centuries in calibrated age. Within a time scale of several decades, we can find several time intervals on the 14 C calibration curve which correspond with periods of rapid increases in atmosp…
Accelerator radiocarbon dating at the molecular level
Status Report of the New AMS 14 C Sample Preparation Lab of the Hertelendi Laboratory of Environmental Studies (Debrecen, Hungary)
We document chemical laboratory procedures and results on international comparison samples at the Hertelendi Laboratory of Environmental Studies, Debrecen, Hungary. We also show results using the new MICADAS system and compare these results to internationally recognized standards and blank materials. The newly developed sample preparation system in HEKAL can handle samples as 1) organic material, 2) cellulose fraction of plant, 3) bones, 4) carbo…
Report on the First Stage of the Iron Age Dating Project in Israel
The traditional chronology of ancient Israel in the 11th–9th centuries BCE was constructed mainly by correlating archaeological phenomena with biblical narratives and with Bible-derived chronology. The chronology of Cyprus and Greece, and hence of points further west, are in turn based on that of the Levant. Thus, a newly proposed chronology, about 75–100 yr lower than the conventional one, bears crucial implications not only for biblical history…
First Direct AMS Dates on Early Maize From Tehuacán, Mexico
The Tehuacán region in Central Mexico is thought to be the locale of origin of Zea mays , or maize, a cultivated plant pivotal in the development of agriculture in the Americas (MacNeish, 1981, 1985). The age of the earliest maize, and its rate of dispersal are thus important components of cultural development in the New World. We have secured permission from the Federal Government of Mexico to date critical specimens from Tehuacán, which represe…
Study of Bone Radiocarbon Dating Accuracy at the University of Arizona NSF Accelerator Facility for Radioisotope Analysis
Bone would seem to be an ideal material for 14 C dating because this calcified tissue contains 20 weight per cent protein. Fossil bone, however, can lose most of its original organic matter and frequently contains contaminants having different 14 C ages. Numerous 14 C dates on bone have been available to archaeologists and geologists but many age determinations have been inaccurate despite over 30 years of research in the field following the firs…
Stepped-Combustion 14 C Dating of Sediment
Radiocarbon dating of bulk sediment has long been used as a method of last resort when reliable wood, charcoal, or plant macrofossils are not available for analysis. Accurate dating of sediment is complicated by the presence of multiple organic carbon fractions, each with a potentially different 14 C activity. Additionally, the presence of carbon bound by clay minerals can significantly reduce the accuracy of a sediment age determination, with th…
The Upper Paleolithic of Mongolia
Chronology of the Obi-Rakhmat Grotto (Uzbekistan)
The Obi-Rakhmat Grotto is one of the key Paleolithic sites in Central Asia. Archaeological excavations have revealed 22 strata containing archaeological materials. Lithic assemblages from all cultural layers display features similar to both late Middle Paleolithic blade industries and early Upper Paleolithic complexes in Southwest Asia and the Siberian Altai Mountains; this suggests a gradual Middle-to-Upper Paleolithic transition occurred in wes…
Dating the Iron Age I/II Transition in Israel
Nearly a decade ago, a different chronology than the conventional absolute chronology for the early Iron Age in Israel was suggested. The new, lower chronology “transfers” Iron Age I and Iron Age IIA contexts in Israel, traditionally dated to the 11th and 10th centuries BCE, to the 10th and 9th centuries, respectively. Thus, it places the Iron I|IIA transition at about 920–900 BCE. This alternative chronology carries important implications for Is…
Production of Graphite Targets by Deposition from CO/H 2 for Precision Accelerator 14 C Measurements
A method has been developed at the Arizona AMS facility for production of graphite directly from CO 2 by catalytic reduction of CO/H 2 mixtures. The method is a modification of procedures discussed by Vogel et al (1984). Currents of 12 C − from these targets vary considerably, but have a median value which is 70% of that achieved from spectroscopic graphite. Precisions of ±60 to 100 yr are routinely achieved for 14 C ages of 5000-yr-old samples c…
Major Revisions in the Pleistocene Age Assignments for North American Human Skeletons by C-14 Accelerator Mass Spectrometry
Radiocarbon analyses by accelerator mass spectrometric (AMS) techniques on organic fractions of human bone from various North American localities previously assigned ages ranging from about 70,000 to 15,000 years B.P. now suggest that none of these skeletons is older than 11,000 C-14 years B.P
More Rapid 14 C Excursions in the Tree-Ring Record
Two radiocarbon ( 14 C) excursions are caused by an increase of incoming cosmic rays on a short time scale found in the Late Holocene (AD 774–775 and AD 993–994), which are widely explained as due to extreme solar proton events (SPE). In addition, a larger event has also been reported at 5480 BC (Miyake et al. 2017a), which is attributed to a special mode of a grand solar minimum, as well as another at 660 BC (Park et al. 2017). Clearly, other ev…
Radiocarbon AMS Dating of Pollen Concentrated from Eolian Sediments
Dating pollen concentrated from eolian sediments provides a new way to establish a chronological framework on the Loess Plateau of China. We show that pollen deposited simultaneously with sediment in a stable environment can provide reliable ages. We suggest that the reliability of pollen dating can be evaluated by comparison with wood cellulose or charcoal ages from the same stratigraphic level. Dating pollen concentrates from the various profil…
Operation of the NSF-Arizona Accelerator Facility for Radioisotope Analysis and Results from Selected Collaborative Research Projects
Radiocarbon dating at the Arizona accelerator facility has improved substantially in the last three years. Since starting to use graphite targets (see Jull et al , 1986), we have been able to obtain routinely a precision of ca ± 1% (ca 80 yr) for relatively modern material. Our routine technique of tuning and operating the tandem accelerator mass spectrometer (TAMS) and our method of calculating 14 C results are discussed in detail. Data on activ…
The Reliability of AMS Radiocarbon Dating of Shells from China
We tested the feasibility of dating freshwater and terrestrial molluscs from the semiarid and arid zone in China, since these types of shell material deposit only aragonite to form their shell structure, and shell integrity can be easily observed using X-ray diffraction. We also tested the possibility of estimating microenvironmental changes from shell δ 13 C values, but variations within shell populations preclude the use of these values as a re…
Radiocarbon Dating of Scrolls and Linen Fragments from the Judean Desert
We report on new 14 C measurements of samples of 18 texts (scrolls) and 2 linen fragments from Qumran Caves 1, 2, and 4 and from Nahal Hever, both in the Dead Sea region. The radiocarbon results are in good agreement with estimates of age based on paleography
Second Radiocarbon Intercomparison Program for the Chauvetpont d'Arc Cave, Ardèche, France
The Chauvet-Pont d'Arc Cave is one of the most important sites for the study of the earliest manifestations and development of prehistoric art at the beginning of the Upper Paleolithic. Different dating techniques have been performed thus far (AMS 14 C, U/Th TIMS, 36 Cl dating) to model the chronological framework of this decorated cave. The cave yielded several large charcoal fragments, which enabled the opportunity for obtaining multiple dates;…
C Chronostratigraphy for Qinghai Lake in China
Radiocarbon accelerator mass spectrometry (AMS) techniques were used to date total organic carbon and plant seeds in the lFs core sequence (36°48′N, 100°08′E) from Qinghai Lake, China. This core was drilled ∼18 m into Qinghai Lake sediments as part of an international cooperative research project, “Scientific Drilling at Qinghai Lake in the Northeastern Tibetan Plateau: High-Resolution Paleoenvironmental Records of Eastern Asia Linked to Global C…
Sample Preparation of Dissolved Organic Carbon in Groundwater for AMS 14 C Analysis
This study describes a sample preparation technique used to isolate dissolved organic carbon (DOC) in groundwater for radiocarbon analysis using accelerator mass spectrometry (AMS). The goal of the work is to improve our ability to determine groundwater residence times based on 14 C measurements of the DOC fraction in groundwater. Water samples were collected from carbonate and volcanic rock aquifers in southern Nevada. Multiple measurements of t…
Radiocarbon Dating of the Stone and Bronze Age Sites in Primorye (Russian Far East)
The first results of radiocarbon dating of the ancient sites in the Russian Far East were published early in the 1960s (Okladnikov 1964). We now have enough data to establish the main features in the 14 C chronology of the Stone and Bronze Age cultures in Primorye, one of the archaeologically well-studied regions of the Russian Far East
The earliest surviving textiles in East Asia from Chertovy Vorota Cave, Primorye Province, Russian Far East
Carbonised textiles were found in a burnt down building inside a cave 30km from the far eastern coast of Russia. The textiles were made from untwisted or hand-twisted blades of sedge grass to form ropes, nets and woven mats. Dated by AMS toc. 9400-8400 cal BP these are the earliest textiles so far known from East Asia
The Radiocarbon Dating and Authentication of Iron Artifacts
The continuing improvements in accelerator mass spectrometry (AMS) dating technology mean that it is possible to work on ever smaller samples, which in turn, make an ever wider range of sample potentially available for dating. This paper discusses some of the difficulties arising with the interpretation of AMS dates obtained from carbon in iron. The overriding problem is that the carbon, now in chemical combination with the iron, could have come …
Adoption and Evaluation of a sample Pretreatment Protocol for Radiocarbon Dating of Cremated Bones at Hekal
A comparative study was undertaken to adopt and evaluate a radiocarbon ( 14 C) preparation procedure for accelerator mass spectrometry (AMS) measurements of cremated bones at our laboratory, including different types of archaeological samples (cremated bone, bone, charcoal, charred grain). All 14 C analyses were performed using the EnvironMICADAS AMS instrument at the Hertelendi Laboratory of Environmental Studies (HEKAL) and the ancillary analys…
Temporal Variation of Atmospheric Fossil and Modern CO 2 Excess at a Central European Rural Tower Station between 2008 and 2014
In 2008, the atmospheric CO 2 measurements at the Hegyhátsál rural tower station were extended further by 14 CO 2 air sampling from two elevations (115 and 10 m a.g.l.), in cooperation with HEKAL (ICER). Since then, a complete six-year-long (2008–2014) dataset of atmospheric CO 2 , Δ 14 C, fossil, and modern CO 2 excess (relative to Jungfraujoch) has been assembled and evaluated. Based on our results, the annual mean CO 2 mole fraction rose at bo…
Chronology of Prehistoric Cultural Complexes of Sakhalin Island (Russian Far East)
A chronological framework for the prehistoric cultural complexes of Sakhalin Island is presented based on 160 radiocarbon dates from 74 sites. The earliest 14 C-dated site, Ogonki 5, corresponds to the Upper Paleolithic, about 19,500–17,800 BP. According to the 14 C data, since about 8800 BP, there is a continuous sequence of Neolithic, Early Iron Age, and Medieval complexes. The Neolithic existed during approximately 8800–2800 BP. Transitional N…
Results of Tests and Measurements from the Nsf Regional Accelerator Facility for Radioisotope Dating
Tests of performance of the tandem accelerator mass spectrometer at the NSF Regional Facility at the University of Arizona are discussed. Results of measurements on some tree rings and on some archaeologic samples are presented
Major Revisions in the Pleistocene Age Assignments for North American Human Skeletons by C-14 Accelerator Mass Spectrometry
Radiocarbon analyses by accelerator mass spectrometric (AMS) techniques on organic fractions of human bone from various North American localities previously assigned ages ranging from about 70,000 to 15,000 years B.P. now suggest that none of these skeletons is older than 11,000 C-14 years B.P
Operation of the NSF-Arizona Accelerator Facility for Radioisotope Analysis and Results from Selected Collaborative Research Projects
Radiocarbon dating at the Arizona accelerator facility has improved substantially in the last three years. Since starting to use graphite targets (see Jull et al , 1986), we have been able to obtain routinely a precision of ca ± 1% (ca 80 yr) for relatively modern material. Our routine technique of tuning and operating the tandem accelerator mass spectrometer (TAMS) and our method of calculating 14 C results are discussed in detail. Data on activ…
Urban Atmospheric 14 CO and 14 CH 4 Measurements by Accelerator Mass Spectrometry
Atmospheric gas samples (0.1m 3 ) were collected at ground level during January/February 1984 in Las Vegas, Nevada for 14 C/ 13 C accelerator mass spectrometry and total abundance measurements of CO and CH 4 . During winter months in this locale, CO concentrations can occur at 10 to 100 times background, occasionally exceeding the National Ambient Air Quality Standard (NAAQS). Methane concentrations show a slight enhancement (∼24%) above the back…
Production of Graphite Targets by Deposition from CO/H 2 for Precision Accelerator 14 C Measurements
A method has been developed at the Arizona AMS facility for production of graphite directly from CO 2 by catalytic reduction of CO/H 2 mixtures. The method is a modification of procedures discussed by Vogel et al (1984). Currents of 12 C − from these targets vary considerably, but have a median value which is 70% of that achieved from spectroscopic graphite. Precisions of ±60 to 100 yr are routinely achieved for 14 C ages of 5000-yr-old samples c…
Radiocarbon and Cation-Radio Ages for Rock Varnish on Tioga and Tahoe Marainal Boulders of Pine Creek, Eastern Sierra Nevada, California, and their Paleoclimatic Implications
Accelerator mass spectrometry 14 C analyses of organic matter extracted from rock varnishes on morainal boulders yield limiting minimum ages for three crests of the Tioga glaciation. At Pine Creek in the eastern Sierra Nevada, varnish started to form on boulders of the outermost Tioga moraine before 19,000 yr B.P., and varnish originated on the innermost Tioga moraine before 13,200 yr B.P. Comparisons with lake-level, paleohydrological, paleoecol…
Study of Bone Radiocarbon Dating Accuracy at the University of Arizona NSF Accelerator Facility for Radioisotope Analysis
Bone would seem to be an ideal material for 14 C dating because this calcified tissue contains 20 weight per cent protein. Fossil bone, however, can lose most of its original organic matter and frequently contains contaminants having different 14 C ages. Numerous 14 C dates on bone have been available to archaeologists and geologists but many age determinations have been inaccurate despite over 30 years of research in the field following the firs…
New radiocarbon dates and Late Palaeolithic diet at Wadi Kubbaniya, Egypt
Vegetable remains are a rarity in Palueolithic contexts. These new determinations on material from southern Egypt establish securely the date of an intensive grass-tuber and fish economy in the Nile Valley towards 20,000 years ago
Application of Tandem Accelerator Mass-Spectrometer Dating to Late Pleistocene-Holocene Sediments of the East Antarctic Continental Shelf
Glacial recession from the Antarctic continental shelf is recorded by glacial-marine diamictons, sands, and overlying siliceous oozes. In order to clarify the chronology for this sequence, use was made of the University of Arizona tandem accelerator mass-spectrometer (TAMS) for 14 C dating. Small samples of benthic and planktonic foraminifera were selectively removed from diamictons, graded sands, and surface sediments which were recovered from t…
Accelerator mass spectrometry
Spallogenic 14C in High-Altitude Rocks and in Antarctic Meteorites
14 C in high-altitude rocks and in Antarctic meteorites of long terrestrial age has been found at levels consistent with in-situ production by cosmic rays. Levels of 0.2–0.59 dpm/kg (or 1.0–2.6 × 10 6 14 C/g) are found in high-altitude samples ranging from 3300 to 5460m. Similar values are observed in Antarctic meteorites that have been dated by 81 Kr by Freundel, Schultz & Reedy (1986) as over 100 kyr old
First Direct AMS Dates on Early Maize From Tehuacán, Mexico
The Tehuacán region in Central Mexico is thought to be the locale of origin of Zea mays , or maize, a cultivated plant pivotal in the development of agriculture in the Americas (MacNeish, 1981, 1985). The age of the earliest maize, and its rate of dispersal are thus important components of cultural development in the New World. We have secured permission from the Federal Government of Mexico to date critical specimens from Tehuacán, which represe…
Radiocarbon in Dissolved Organic and Inorganic Carbon From the Central North Pacific
Radiocarbon measurements are reported for dissolved organic carbon (DOC) and inorganic carbon (DIC) from seawater samples collected from the Alcyone-5 cruise in the central North Pacific Ocean in 1985. Differences between the UV-radiation techniques used here and those reported by Williams, Oeschger and Kinney (1969) to oxidize and recover the DOC from sea water are presented. UV unoxidizable DOC in these samples is discussed in a separate public…
Radiocarbon Dating of Deep-Sea Sediments
Radiocarbon dating (Libby, 1955) has been an important tool in the marine sciences since the early 1950s (eg, Arrhenius, Kjellberg & Libby, 1951; Ericson et al , 1956; Broecker, Ewing & Heezen, 1960; Emery & Bray, 1962) and the basic principles and analytic procedures of the method have changed little. In the late 1970s, the Accelerator Mass Spectrometer (AMS) method of 14 C dating was developed (Bennett et al , 1977, 1978), the major advantages …
Accuracy of North American Human Skeleton Ages
Accelerator mass spectrometry (AMS) radiocarbon dates fail to provide conclusive evidence that all New World human fossils are younger than approximately 11,000 yr. Because fossil bones vary widely in preservation, their radiocarbon dates are not equally accurate. Molecular-level radiocarbon dating, which used individual amino acids to assess fossil diagenesis, revealed that dates on known-age, noncollagenous bone were underestimated by at least …
Chronology of Holocene vertebrate extinction in the Galápagos Islands
Eleven conventional and 15 AMS (accelerator mass spectrometer) radiocarbon dates establish chronologies for nine Holocene vertebrate fossil sites in the Galápagos Islands, Ecuador. A Holocene fossil record approaching 500,000 bones, more than 90% of which predate the arrival of people, shows that most or all cases of extinction or extirpation in the Galápagos occurred after first human contact in AD 1535. This is especially significant for two sp…
Revised age of deglaciation of Lake Emma based on new radiocarbon and macrofossil analyses
Previous radiocarbon ages of detrital moss fragments in basal organic sediments of Lake Emma indicated that extensive deglaciation of the San Juan Mountains occurred prior to 14,900 yr B.P. (Carrara et al. , 1984). Paleoecological analyses of insect and plant macrofossils from these basal sediments cast doubt on the reliability of the radiocarbon ages. Subsequent accelerator radiocarbon dates of insect fossils and wood fragments indicate an early…
Accelerator radiocarbon dating at the molecular level
Cosmogenic Nuclides in Ice Sheets
We discuss the nature of the twofold record of cosmogenic nuclides in ice sheets, of nuclei produced in the atmosphere, and of nuclei produced in situ due to interactions of cosmic-ray particles with oxygen nuclei in ice. We show that a wealth of geophysical information, in principle, can be derived from a suitable combination of nuclides in ice deposited at different latitudes. Such knowledge includes temporal changes in the cosmic-ray flux, in …
Measurements of Cosmogenic 14 C Produced by Spallation in High-Altitude Rocks
The production of radioisotopes at the Earth's surface by cosmic-ray effects has been discussed for many years. Only in the past few years, with the higher sensitivity provided by accelerator mass spectrometry (AMS) in detecting 10 Be, 26 A1 and 36 Cl, have the radioisotopes produced in this way been measured. We report here our measurements of cosmogenic 14 C in terrestrial rocks at high altitude, and comparisons to other exposure-dating methods
C Profiles in the Norwegian and Greenland Seas by Conventional and AMS Measurements
CO 2 in the atmosphere is an important climate gas because of its absorption of infrared radiation. More knowledge about CO 2 uptake in the ocean is of critical significance in predicting future climate development. For a period of approximately 30 years, radioactive carbon from nuclear tests has been a very useful tracer in CO 2 exchange studies. Up to now, the measurements have been based mainly on the conventional counting technique with large…
Pleistocene Geochronology and Palaeothermometry from Protein Diagenesis in Ostrich Eggshells
Pleistocene Geochronology and Palaeothermometry from Protein Diagenesis in Ostrich Eggshells: Implications for the Evolution of Modern Humans was published in The Origin of Modern Humans and the Impact of Chronometric Dating on page 49
C Dating of Laser-Oxidized Organics
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 14 C 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 …
Late Quaternary (Stage 2 and 3) Meltwater and Heinrich Events, Northwest Labrador Sea
Two major meltwater events are documented in cores from the NW Labrador Sea. One occurred ca. 20,000 14 C yr B.P. in association with deposition of a major detrital carbonate unit. Both prior to and after this event, δ 18 O values of near-surface planktonic foraminifera were 4.5%, indicating fully enriched glacial values. A younger event (ca. 14,000 14 C yr B.P.) is characterized by a dramatic change in δ 18 O from 4.5 to 2.0% and coincided with …
Dating of the Basal Aurignacian Sandwich at Abric Romanı́ (Catalunya, Spain) by Radiocarbon and Uranium-Series
Radiocarbon dating (108 works) · Geology (97 works) · Archaeology and ancient environmental studies (71 works) · Geology and Paleoclimatology Research (70 works) · Archaeology (68 works) · Paleontology (68 works) · Geography (67 works) · Chemistry (48 works) · Accelerator mass spectrometry (39 works) · Isotope Analysis in Ecology (35 works)