George S Burr
Biographic Data
| ID | 285181 |
|---|---|
| NAME | George S Burr |
| GIVEN NAMES | George S |
| FAMILY NAME | Burr |
| SIGNATURE | BURR G S |
| AFFILIATIONS | University of Arizona |
| ORCID | 0000-0003-0068-7589 |
| VERIFIED | Yes |
| TOTAL WORKS | 49 |
| TOTAL CITATIONS | 4255 |
| AUTHOR COUNT | 49 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1992 |
| LATEST PUBLICATION YEAR | 2022 |
| H-INDEX | 8 |
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…
Meyer Rubin—a Radiocarbon Pioneer
was a pioneer in the field of radiocarbon. In 1950, after serving in World War II, he began his career as a geologist at the United States Geological Survey (USGS). He joined the survey's radiocarbon laboratory on December 1, 1953, under Hans Suess (Suess 1954a). Suess constructed an acetylene gas 14 C betacounting laboratory that extended the age limit of the Libby 14 C solid graphite method by several half-lives (Suess 1954b; After Suess left, …
East Asian winter monsoon variation during the last 3000 years as recorded in a subtropical mountain lake, northeastern Taiwan
The East Asian Winter Monsoon (EAWM) is a fundamental part of the global monsoon system that affects nearly one-quarter of the world’s population. Robust paleoclimate reconstructions in East Asia are complicated by multiple sources of precipitation. These sources, such as the EAWM and typhoons, need to be disentangled in order to understand the dominant source of precipitation influencing the past and current climate. Taiwan, situated within the …
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.…
Climatic control of orbital time-scale wildfire occurrences since the late MIS 3 at Qinghai Lake, monsoon marginal zone
High resolution record of heavy metals from estuary sediments of Nankan River (Taiwan) assessed by rigorous multivariate statistical analysis
Holocene variation of radiocarbon reservoir age offshore western Taiwan, derived from paired charcoals and mollusks
The great cultural divergence and environmental background of Northern Shaanxi and its adjacent regions during the late Neolithic
Sea level implications from Late Quaternary/Holocene paleosols from the Oujiang Delta, China
We describe two coastal paleosols recovered in sediment cores from the Oujiang Delta, Southeast China. These provide useful benchmarks for past sea level change on the East China Sea coast. Radiocarbon ( 14 C) dates on charcoal and plant matter show that one formed during Marine Isotope Stage 3 (MIS 3) and was exposed for perhaps 20 ka, during the Last Glacial Maximum. The other formed in the Early Holocene and was briefly exposed, during a perio…
Holocene Precipitation Records from Inner Mongolia Derived from Hydrogen Isotope Compositions of Sediment Fatty Acids
The Inner Mongolian Plateau lies along the northern limit reached by the East Asian summer monsoon. This geographic setting makes it especially sensitive to environmental change and an excellent site for understanding Quaternary East Asian monsoon variability. In this study we present new results of hydrogen isotopic compositions of fatty acids extracted from sediments, which were used to construct Holocene paleoprecipitation (or moisture) change…
Dissolved Inorganic and Organic Carbon in an Ephemeral Fresh Water Stream in Southern Arizona
We report on an initial long-term study of dissolved inorganic and organic carbon (DIC) from Sabino Creek, located in Sabino Canyon, Pima County, Arizona. The purpose of this study was to monitor changes in dissolved radiocarbon ( 14 C) with time and to understand the processes contributing to these variations. Our results span the period 2009–2016 and show a mixing trend between dissolved inorganic and organic carbon modern end-members with an o…
Out of the Cave and into the Light
Climate Change, Desertification, and Societal Responses along the Mu Us Desert Margin during the Ming Dynasty
Historical records for the Mu Us Desert margin during the Ming dynasty (1368–1644) and corresponding high-resolution climate proxy records have prompted studies on societal responses to climatic changes in this region. The Mu Us Desert margin is highly sensitive to changes in desertification and biological productivity controlled in part by Asian monsoon variations. Here the existing historical temperature and precipitation records are examined t…
Paleodietary Analysis of Humans in Guanzhong Basin, Shaanxi Province Since 8000 BP
We identified human paleodietary changes from inhabitants of the Guanzhong basin since 8000 BP, based on published carbon and nitrogen isotopic measurements on bones, fauna and plant remains. We also directly measured 14 C ages, δ 13 C and δ 15 N values from bones unearthed at the Zhouyuan site, west of Guanzhong, in order to reconstruct paleodietary changes of the ancient inhabitants. We found that during the Laoguantai period, animal foods were…
Preliminary Investigation on the Rapid and Direct AMS Measurement of 129 I in Environmental Samples without Chemical Separation
Accelerator mass spectrometry (AMS) is the most sensitive method for measuring 129 I in environmental samples available today, with a detection limit of about 10 –15 for 129 I/ 127 I. A drawback of the technique is the time-consuming chemical separation required to prepare AMS targets from raw samples. This step significantly limits applications requiring rapid analyses and large numbers of samples, for example, in monitoring studies associated w…
Dating surface assemblages using pottery and eggshell
Temporal Variations of Radiocarbon Reservoir Ages in the South Pacific Ocean during the Holocene
This article discusses the magnitude and rate of change of radiocarbon reservoir ages from the surface ocean in the South Pacific during the Holocene. 14 C reservoir ages are calculated from paired U/Th and 14 C measurements. Seventeen pairs of coral dates were determined from samples collected on Rendova and Tetepare Islands, in the Solomon Islands, and from Espiritu Santo Island, Vanuatu. The samples are all Holocene in age, with 230 Th ages ra…
Late Pleistocene sedimentary history of multiple glacially dammed lake episodes along the Yarlung-Tsangpo river, southeast Tibet
We present a reconstructed lithologic column compiled from a series of lacustrine outcrops along a tributary of the Nyang River, a major tributary of the Yarlung-Tsangpo in southeast Tibet. The deposits were preserved between terraces at altitudes of 2950–3100 m asl. The stratigraphic record features at least two sets of coarsening-upward sequences depicting episodic aggradation and progradation of a glacially dammed lake related delta. Recognize…
Testing the Accuracy of 14 C Age Data from Pollen Concentrates in the Yangtze Delta, China
In order to test the accuracy of accelerator mass spectrometry (AMS) radiocarbon dating of pollen, 8 samples of pollen concentrates and 4 bulk organic samples were collected and analyzed from trench T1041 at the Tianluoshan site, Yuyao city, Zhejiang Province. This site was chosen because a reliable chronology had been previously established there based on radiocarbon dates of plant materials. The pollen concentrate samples were measured using AM…
Radiocarbon dating, reservoir effects, and calibration
Radionuclide Studies of Stony Meteorites from Hot Deserts
We summarize the use of radiocarbon produced by spallation in meteorites in space to determine their terrestrial age or residence time. This “age” gives us important information as it can be compared to the rates of weathering and infall of meteorites. The processes that affect the collection of meteorites in a given area can be related to the rates of infall of new meteorites, and the rate of removal by chemical weathering and physical erosion
Low-Temperature and Temperature Stepped-Combustion of Terrace Sediments from Nanfu, Taiwan
We discuss a radiocarbon study of sediment samples collected from Nanfu terrace in western Taiwan. From these, we extracted humic acids (HA) and humin from the very fine and coarse grain-size fractions using a standard acid-alkali-acid pretreatment. The humin extracts were combusted at 400 and 1100 °C by stepped-combustion, to yield a low-temperature (LT) carbon component and a high-temperature (HT) carbon component. We compare the ages of the LT…
Chronology of the perishables
Intriguing wooden objects, excavated (mostly unstratigraphically) from peat bogs in the Trans-Urals region of Russia, are here dated by AMS and found to belong to the Aeneolithic and Bronze Age. In spite of a long sojourn in museums, and conservation with various chemicals, the dates obtained were consistent and reliable
Chronology of Late Pleistocene Humans in Eurasia
A compilation of direct age determinations for Late Pleistocene human fossils in eastern Europe and Asia is presented in this paper, and current problems with the dating of hominids in these regions are discussed. Only 25 human finds (4 Neanderthals and 21 modern humans) have been directly dated from Pleistocene eastern Europe and Asia. Indirect dating of human remains (using presumably associated organics) often is insecure, especially when info…
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
IntCal09 and Marine09 Radiocarbon Age Calibration Curves, 0-50,000 Years cal BP
The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14 C and calendar timescales as established in 2002. No change was made to the curves…
INTCAL98 Radiocarbon Age Calibration, 24,000-0 cal BP
The focus of this paper is the conversion of radiocarbon ages to calibrated (cal) ages for the interval 24,000-0 cal BP (Before Present, 0 cal BP = AD 1950), based upon a sample set of dendrochronologically dated tree rings, uranium-thorium dated corals, and varve-counted marine sediment. The 14 C age-cal age information, produced by many laboratories, is converted to Δ 14 C profiles and calibration curves, for the atmosphere as well as the ocean…
Intcal04 Terrestrial Radiocarbon Age Calibration, 0–26 Cal Kyr BP
A new calibration curve for the conversion of radiocarbon ages to calibrated (cal) ages has been constructed and internationally ratified to replace IntCal98, which extended from 0–24 cal kyr BP (Before Present, 0 cal BP = AD 1950). The new calibration data set for terrestrial samples extends from 0–26 cal kyr BP, but with much higher resolution beyond 11.4 cal kyr BP than IntCal98. Dendrochronologically-dated tree-ring samples cover the period f…
Marine04 Marine Radiocarbon Age Calibration, 0–26 Cal Kyr Bp
New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring…
AMS 14C dating the Protoaurignacian/Early Aurignacian of Isturitz, France. Implications for Neanderthal–modern human interaction and the timing of technical and cultural innovations in Europe
Dating North Asian surface assemblages with ostrich eggshell
Dating surface assemblages using pottery and eggshell
Anomalous 11-Year Δ 14 C Cycle at High Latitudes
We find no evidence for an anomalously intense 11-yr cycle in Δ 14 C at high latitudes during the period, AD 1870–1885, as reported by Fan et al . (1983, 1986). However, there does appear to be a regional effect within the MacKenzie River region (67°N, 130°W), with atmospheric 14 C depressed by relative to the Olympic Peninsula. Such an effect would require only 5% of CO 2 in the air mass to have been derived from 5% 14 C-depleted soil gas CO 2 .…
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
Comparisons and Interpretations of Charcoal and Organic Matter Radiocarbon Ages from Buried Soils in North-Central Colorado, USA
The reliability of radiocarbon ages based on soil organic matter (SOM) from Holocene buried soils in Middle Park, Colorado, is assessed by comparison with ages of charcoal. On average, 14 C ages of SOM from buried surface horizons are 880 ± 230 14 C yr younger than charcoal ages from the same horizon. Humic acid (HA) and low-temperature (400 °) combustion residue (LT) fractions are 390 ± 230 and 1290 ± 230 14 C yr younger than charcoal ages, resp…
Chronology of the perishables
Intriguing wooden objects, excavated (mostly unstratigraphically) from peat bogs in the Trans-Urals region of Russia, are here dated by AMS and found to belong to the Aeneolithic and Bronze Age. In spite of a long sojourn in museums, and conservation with various chemicals, the dates obtained were consistent and reliable
C Wiggle Matching of the ‘Floating’ Tree-Ring Chronology from the Altai Mountains, Southern Siberia
The Bayesian approach to calibration of radiocarbon dates was used to wiggle-match the “floating” tree-ring chronology from a Pazyryk culture (Scythian-type complex from Sayan-Altai Mountain system, southern Siberia) burial ground in order to estimate the calendar age of its construction. Seventeen bidecadal tree-ring samples were 14 C dated with high precision (±20–30 yr). The results of wiggle-matching show that the Pazyryk-type burial mounds i…
Radiocarbon dating of primary aragonite by sequential extraction of CO 2
This paper describes the potential of correcting the 14 C age shift resulting from the contamination of primary aragonites by detrital carbonates using online sequential extraction of CO 2 . The experiments were carried out on laminated lacustrine aragonites collected from Holocene Dead Sea sediment sections. X-ray diffraction analysis revealed the presence of detrital calcite interpreted to originate from the watershed and transported to the lak…
Out of the Cave and into the Light
A Time History of Pre- and Post-Bomb Radiocarbon in the Barents Sea Derived from Arcto-Norwegian Cod Otoliths
Radiocarbon measured in seawater dissolved inorganic carbon (DIC) can be used to investigate ocean circulation, atmosphere/ocean carbon flux, and provide powerful constraints for the fine-tuning of general circulation models (GCMs). Time series of 14 C in seawater are derived most frequently from annual bands of hermatypic corals. However, this proxy is unavailable in temperate and polar oceans. Fish otoliths, calcium carbonate auditory, and grav…
Regional Radiocarbon Effect Due to Thawing of Frozen Earth
Accelerator mass spectrometry (AMS) measurement of 25 single-year tree rings from AD 1861–1885 at ca. ±3.5‰ precision shows no evidence of an anomalous 11-yr cycle of 14 C near the Arctic Circle in the Mackenzie River area. However, the Δ 14 C measurements are lower on average by 2.7 ± 0.9 (ō)‰ relative to 14 C measurements on tree rings from the Pacific Northwest (Stuiver and Braziunas 1993). We attribute this depression of Δ 14 C to thawing of …
The great cultural divergence and environmental background of Northern Shaanxi and its adjacent regions during the late Neolithic
Low-Temperature and Temperature Stepped-Combustion of Terrace Sediments from Nanfu, Taiwan
We discuss a radiocarbon study of sediment samples collected from Nanfu terrace in western Taiwan. From these, we extracted humic acids (HA) and humin from the very fine and coarse grain-size fractions using a standard acid-alkali-acid pretreatment. The humin extracts were combusted at 400 and 1100 °C by stepped-combustion, to yield a low-temperature (LT) carbon component and a high-temperature (HT) carbon component. We compare the ages of the LT…
Reconstruction of 130-kyr Relative Geomagnetic Intensities from 10 Be in Two Chinese Loess Sections
Efforts to extract weak geomagnetic excursion signals from Chinese loess-paleosol 10 Be have generally been unsuccessful due to the complexities of its accumulation, because the geomagnetic and climate (precipitation and dust) signals contained in loess-paleosol sequence are tightly overprinted. Here, we present a reconstruction of geomagnetic relative paleointensities for the past 130 kyr from 10 Be records in 2 Chinese loess-paleosol sections u…
Radiocarbon in the Water Column of the Southwestern North Pacific Ocean—24 Years After Geosecs
In the framework of the Worldwide Marine Radioactivity Studies (WOMARS) project, water profile samples for radiocarbon measurements were taken during the IAEA'97 cruise at 10 stations in the southwestern North Pacific Ocean. While 14 C concentrations were rapidly decreasing from the surface (Δ 14 C about 100‰) down to about 800 m at all visited stations (Δ 14 C about −200‰), the concentrations below 1000 m were almost constant. Some stations were…
Radiocarbon Beyond this World
In this paper, we review the production of radiocarbon and other radionuclides in extraterrestrial materials. This radioactivity can be produced by the effects of solar and galactic cosmic rays on solid material in space. In addition, direct implantation at the lunar surface of 14 C and other radionuclides can occur. The level of 14 C and other radionuclides in a meteorite can be used to determine its residence time on the Earth's surface, or “te…
Temporal Variations of Radiocarbon Reservoir Ages in the South Pacific Ocean during the Holocene
This article discusses the magnitude and rate of change of radiocarbon reservoir ages from the surface ocean in the South Pacific during the Holocene. 14 C reservoir ages are calculated from paired U/Th and 14 C measurements. Seventeen pairs of coral dates were determined from samples collected on Rendova and Tetepare Islands, in the Solomon Islands, and from Espiritu Santo Island, Vanuatu. The samples are all Holocene in age, with 230 Th ages ra…
Radionuclide Studies of Stony Meteorites from Hot Deserts
We summarize the use of radiocarbon produced by spallation in meteorites in space to determine their terrestrial age or residence time. This “age” gives us important information as it can be compared to the rates of weathering and infall of meteorites. The processes that affect the collection of meteorites in a given area can be related to the rates of infall of new meteorites, and the rate of removal by chemical weathering and physical erosion
Chronology of Late Pleistocene Humans in Eurasia
A compilation of direct age determinations for Late Pleistocene human fossils in eastern Europe and Asia is presented in this paper, and current problems with the dating of hominids in these regions are discussed. Only 25 human finds (4 Neanderthals and 21 modern humans) have been directly dated from Pleistocene eastern Europe and Asia. Indirect dating of human remains (using presumably associated organics) often is insecure, especially when info…
A Thermal and Acid Treatment for Carbon Extraction from Cast Iron and Its Application to Ams Dating of Cast Iron Objects from Ancient Korea
A method of thermal and acid treatments was developed at the Archaeo-metallurgy Laboratory of Hongik University in Korea to extract carbon from cast iron, and carbon objects thus prepared from cast iron artifacts of ancient Korea were dated at the University of Arizona's AMS Facility. The thermal treatments consist of heating a specimen to ∼1000 °C in a controlled environment with reduced oxygen potential, then cooling it rapidly to room temperat…
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
Anomalous 11-Year Δ 14 C Cycle at High Latitudes
We find no evidence for an anomalously intense 11-yr cycle in Δ 14 C at high latitudes during the period, AD 1870–1885, as reported by Fan et al . (1983, 1986). However, there does appear to be a regional effect within the MacKenzie River region (67°N, 130°W), with atmospheric 14 C depressed by relative to the Olympic Peninsula. Such an effect would require only 5% of CO 2 in the air mass to have been derived from 5% 14 C-depleted soil gas CO 2 .…
A Large Drop in Atmospheric 14 C/ 12 C and Reduced Melting in the Younger Dryas, Documented with 230 Th Ages of Corals
Paired carbon-14 ( 14 C) and thorium-230( 230 Th) ages were determined on fossil corals from the Huon Peninsula, Papua New Guinea. The ages were used to calibrate part of the 14 C time scale and to estimate rates of sea-level rise during the last deglaciation. An abrupt offset between the 14 C and 230 Th ages suggests that the atmospheric 14 C/ 12 C ratio dropped by 15 percent during the latter part of and after the Younger Dryas (YD). This promi…
Intercomparison of High-Precision ∆ 14 C Analyses Using Gas Counting and AMS
We report results of a three-year intercomparison experiment between the WHOI Radiocarbon Laboratory (now at University of California, Irvine) and the NSF-University of Arizona AMS Laboratory. The purpose of this study was to compare high-precision measurements of samples obtained routinely using gas proportional counting techniques with results obtained using AMS techniques. Three sets of annually banded, modern coral samples were used for the i…
Regional Radiocarbon Effect Due to Thawing of Frozen Earth
Accelerator mass spectrometry (AMS) measurement of 25 single-year tree rings from AD 1861–1885 at ca. ±3.5‰ precision shows no evidence of an anomalous 11-yr cycle of 14 C near the Arctic Circle in the Mackenzie River area. However, the Δ 14 C measurements are lower on average by 2.7 ± 0.9 (ō)‰ relative to 14 C measurements on tree rings from the Pacific Northwest (Stuiver and Braziunas 1993). We attribute this depression of Δ 14 C to thawing of …
INTCAL98 Radiocarbon Age Calibration, 24,000-0 cal BP
The focus of this paper is the conversion of radiocarbon ages to calibrated (cal) ages for the interval 24,000-0 cal BP (Before Present, 0 cal BP = AD 1950), based upon a sample set of dendrochronologically dated tree rings, uranium-thorium dated corals, and varve-counted marine sediment. The 14 C age-cal age information, produced by many laboratories, is converted to Δ 14 C profiles and calibration curves, for the atmosphere as well as the ocean…
Radiocarbon Beyond this World
In this paper, we review the production of radiocarbon and other radionuclides in extraterrestrial materials. This radioactivity can be produced by the effects of solar and galactic cosmic rays on solid material in space. In addition, direct implantation at the lunar surface of 14 C and other radionuclides can occur. The level of 14 C and other radionuclides in a meteorite can be used to determine its residence time on the Earth's surface, or “te…
Extremely Large Variations of Atmospheric 14 C Concentration During the Last Glacial Period
A long record of atmospheric 14 C concentration, from 45 to 11 thousand years ago (ka), was obtained from a stalagmite with thermal-ionization mass-spectrometric 230 Th and accelerator mass-spectrometric 14 C measurements. This record reveals highly elevated Δ 14 C between 45 and 33 ka, portions of which may correlate with peaks in cosmogenic 36 Cl and 10 Be isotopes observed in polar ice cores. Superimposed on this broad peak of Δ 14 C are sever…
C Wiggle Matching of the ‘Floating’ Tree-Ring Chronology from the Altai Mountains, Southern Siberia
The Bayesian approach to calibration of radiocarbon dates was used to wiggle-match the “floating” tree-ring chronology from a Pazyryk culture (Scythian-type complex from Sayan-Altai Mountain system, southern Siberia) burial ground in order to estimate the calendar age of its construction. Seventeen bidecadal tree-ring samples were 14 C dated with high precision (±20–30 yr). The results of wiggle-matching show that the Pazyryk-type burial mounds i…
A Time History of Pre- and Post-Bomb Radiocarbon in the Barents Sea Derived from Arcto-Norwegian Cod Otoliths
Radiocarbon measured in seawater dissolved inorganic carbon (DIC) can be used to investigate ocean circulation, atmosphere/ocean carbon flux, and provide powerful constraints for the fine-tuning of general circulation models (GCMs). Time series of 14 C in seawater are derived most frequently from annual bands of hermatypic corals. However, this proxy is unavailable in temperate and polar oceans. Fish otoliths, calcium carbonate auditory, and grav…
High-resolution evidence from southern China of an early holocene optimum and a mid-Holocene dry event during the Past 18,000 Years
Computer models suggest that the Holocene Optimum for East Asian summer monsoon precipitation occurred at different times in different regions of China. Previous studies indicate that this time-transgressive Holocene Optimum should have been experienced about 3000 yr ago in southern China. In this study we describe a section which allows us to test this timing directly. We have closely examined high-resolution eutrophic peat/mud sequences coverin…
Intcal04 Terrestrial Radiocarbon Age Calibration, 0–26 Cal Kyr BP
A new calibration curve for the conversion of radiocarbon ages to calibrated (cal) ages has been constructed and internationally ratified to replace IntCal98, which extended from 0–24 cal kyr BP (Before Present, 0 cal BP = AD 1950). The new calibration data set for terrestrial samples extends from 0–26 cal kyr BP, but with much higher resolution beyond 11.4 cal kyr BP than IntCal98. Dendrochronologically-dated tree-ring samples cover the period f…
Marine04 Marine Radiocarbon Age Calibration, 0–26 Cal Kyr Bp
New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring…
Radiocarbon in the Water Column of the Southwestern North Pacific Ocean—24 Years After Geosecs
In the framework of the Worldwide Marine Radioactivity Studies (WOMARS) project, water profile samples for radiocarbon measurements were taken during the IAEA'97 cruise at 10 stations in the southwestern North Pacific Ocean. While 14 C concentrations were rapidly decreasing from the surface (Δ 14 C about 100‰) down to about 800 m at all visited stations (Δ 14 C about −200‰), the concentrations below 1000 m were almost constant. Some stations were…
Paleoproductivity Variations in the Equatorial Arabian Sea
We analyzed a sediment core from the equatorial Arabian Sea, chronologically constrained by accurate accelerator mass spectrometry (AMS) radiocarbon dates on selected planktonic foraminiferal species, for paleoproductivity variations corresponding to the variations in the Indian Ocean Equatorial Westerlies (IEW). The IEW in turn are positively correlated to the Southern Oscillation Index (SOI), which is a measure of El Niño, Southwest monsoon (SW…
Radiocarbon dating of primary aragonite by sequential extraction of CO 2
This paper describes the potential of correcting the 14 C age shift resulting from the contamination of primary aragonites by detrital carbonates using online sequential extraction of CO 2 . The experiments were carried out on laminated lacustrine aragonites collected from Holocene Dead Sea sediment sections. X-ray diffraction analysis revealed the presence of detrital calcite interpreted to originate from the watershed and transported to the lak…
Comparisons and Interpretations of Charcoal and Organic Matter Radiocarbon Ages from Buried Soils in North-Central Colorado, USA
The reliability of radiocarbon ages based on soil organic matter (SOM) from Holocene buried soils in Middle Park, Colorado, is assessed by comparison with ages of charcoal. On average, 14 C ages of SOM from buried surface horizons are 880 ± 230 14 C yr younger than charcoal ages from the same horizon. Humic acid (HA) and low-temperature (400 °) combustion residue (LT) fractions are 390 ± 230 and 1290 ± 230 14 C yr younger than charcoal ages, resp…
AMS 14C dating the Protoaurignacian/Early Aurignacian of Isturitz, France. Implications for Neanderthal–modern human interaction and the timing of technical and cultural innovations in Europe
Dating North Asian surface assemblages with ostrich eggshell
IntCal09 and Marine09 Radiocarbon Age Calibration Curves, 0-50,000 Years cal BP
The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14 C and calendar timescales as established in 2002. No change was made to the curves…
Climatology of the Eastern Arabian Sea during the last glacial Cycle reconstructed from paired measurement of foraminiferal δ 18 O and Mg/Ca
Paired measurements of Mg/Ca and δ 18 O of Globigerenoides sacculifer from an Eastern Arabian Sea (EAS) sediment core indicate that sea-surface temperature (SST) varied within 2°C and sea-surface salinity within 2 psu during the last 100 ka. SST was coldest (∽ 27°C) during Marine Isotope Stage (MIS) 4 and 2. Sea-surface salinity was highest (∽ 37.5 psu) during most of the last glacial period (∽ 60–18 ka), concurrent with increased δ 18 O G.saccul…
A Thermal and Acid Treatment for Carbon Extraction from Cast Iron and Its Application to Ams Dating of Cast Iron Objects from Ancient Korea
A method of thermal and acid treatments was developed at the Archaeo-metallurgy Laboratory of Hongik University in Korea to extract carbon from cast iron, and carbon objects thus prepared from cast iron artifacts of ancient Korea were dated at the University of Arizona's AMS Facility. The thermal treatments consist of heating a specimen to ∼1000 °C in a controlled environment with reduced oxygen potential, then cooling it rapidly to room temperat…
Reconstruction of 130-kyr Relative Geomagnetic Intensities from 10 Be in Two Chinese Loess Sections
Efforts to extract weak geomagnetic excursion signals from Chinese loess-paleosol 10 Be have generally been unsuccessful due to the complexities of its accumulation, because the geomagnetic and climate (precipitation and dust) signals contained in loess-paleosol sequence are tightly overprinted. Here, we present a reconstruction of geomagnetic relative paleointensities for the past 130 kyr from 10 Be records in 2 Chinese loess-paleosol sections u…
Environmental Changes of the Aral Sea (Central Asia) in the Holocene
Changes of the Aral Sea level have been observed in 3 sediment boreholes, 2 outcrops, and associated archaeological sites. The obtained results are supported by 25 radiocarbon dates. Major trends of lake-level changes have been reconstructed in some detail for the last 2000 yr, and additional data provide an outline of fluctuations throughout the Holocene. Several distinct changes are shown to precede the modern, human-induced regression of the A…
Chronology of Late Pleistocene Humans in Eurasia
A compilation of direct age determinations for Late Pleistocene human fossils in eastern Europe and Asia is presented in this paper, and current problems with the dating of hominids in these regions are discussed. Only 25 human finds (4 Neanderthals and 21 modern humans) have been directly dated from Pleistocene eastern Europe and Asia. Indirect dating of human remains (using presumably associated organics) often is insecure, especially when info…
Geology (38 works) · Geology and Paleoclimatology Research (34 works) · Radiocarbon dating (32 works) · Geography (29 works) · Paleontology (29 works) · Archaeology and ancient environmental studies (23 works) · Archaeology (19 works) · Physical geography (18 works) · Holocene (16 works) · Oceanography (16 works)