Stewart P H T Freeman
Dados Biográficos
| ID | 4129636 |
|---|---|
| NOME | Stewart P H T Freeman |
| PRENOMES | Stewart P H T |
| SOBRENOME | Freeman |
| ASSINATURA | FREEMAN S P H T |
| AFILIAÇÕES | Scottish Enterprise |
| ORCID | 0000-0001-6148-3171 |
| VERIFICADO | Sim |
| TOTAL DE OBRAS | 8 |
| TOTAL DE CITAÇÕES | 66 |
| TOTAL COMO AUTOR | 8 |
| TOTAL COMO EDITOR | 0 |
| PRIMEIRO ANO DE PUBLICAÇÃO | 2005 |
| ANO MAIS RECENTE DE PUBLICAÇÃO | 2026 |
| ÍNDICE H | 3 |
Direct radiocarbon ( 14 C) analysis of methane using positive ion mass spectrometry
The reduction of anthropogenic methane emissions is a priority due to its potent global warming potential. Radiocarbon ( 14 C) can distinguish between methane from natural biogenic and fossil fuel sources, however, the analysis of methane 14 C by conventional accelerator mass spectrometry (AMS) techniques is demanding. At SUERC, a prototype positive ion mass spectrometer (PIMS) is set up to directly analyze 14 C in methane with minimal sample pre…
Radiocarbon Dating of Fugendake Volcano in Unzen, SW Japan
This article presents new radiocarbon ages for the lavas, pyroclastic flow, and lahar deposits that originated from the Fugendake and Mayuyama volcanoes of the Younger Unzen Volcano, SW Japan. Nine charcoal samples were collected from the lavas and pyroclastic flow deposits, and 17 soil samples from the underlying volcanic-related products. This data set, together with previously published ages (thermoluminescence, K-Ar, fission track, and 14 C),…
Cosmogenic 10 Be and 26 Al ages of Holocene moraines in southern Norway I
Cosmogenic nuclide dating ( 10 Be and 26 Al) is applied to boulders on two moraine ridges at the type-site of the early-Holocene Erdalen Event, southern Norway, dated previously using radiocarbon. Quartz-rich rock samples yielded 10 Be age estimates between 9.8 ± 1.2 and 10.1 ± 1.1 ka (external uncertainties, ± 1σ), with an average of 9.95 ka. These age estimates are statistically indistinguishable from the independent radiocarbon age estimate. 2…
The use of ‘bomb spike’ calibration and high-precision AMS 14 C analyses to date salt-marsh sediments deposited during the past three centuries
A combination of ‘bomb spike’ calibration and conventional calibration of AMS 14 C dating has been used to determine a detailed age-depth model for a 1-m sediment section collected from a salt marsh in Poole Harbour, southern England. These data were compared with the chronology obtained from 210 Pb analysis and 137 Cs age markers. We report post bomb values of over 1.46 F 14 C (> 146% modern 14 C), and both the rising and falling limbs of the at…
A Cremated Bone Intercomparison Study
It is now almost 10 yr since radiocarbon dating of cremated bone was first developed using the small carbonate component contained within the hydroxyapatite-based inorganic fraction. Currently, a significant number of 14 C laboratories date cremated bone as part of their routine dating service. As a general investigation of cremated bone dating since this initial development, a small, cremated bone intercomparison study took place in 2005, involv…
Investigation into Background Levels of Small Organic Samples at the Nerc Radiocarbon Laboratory
Recent progress in preparation/combustion of submilligram organic samples at our laboratories is presented. Routine methods had to be modified/refined to achieve acceptable and consistent procedural blanks for organic samples smaller than 1000 μg C. A description of the process leading to a modified combustion method for smaller organic samples is given in detail. In addition to analyzing different background materials, the influence of different…
Influence of Mollusk Species on Marine ΔR Determinations
Radiocarbon ages were measured on replicate samples of burnt grain and 5 mollusk species collected from a single sealed layer at an archaeological site (Hornish Point) on the west coast of South Uist, Scotland. The aim was to examine the impact of using different mollusk species on ΔR determinations that are calculated using the paired terrestrial/marine sample approach. The mollusk species examined inhabit a range of environments and utilize a v…
Progress in AMS Target Production of Sub-Milligram Samples at the Nerc Radiocarbon Laboratory
Recent progress in graphite target production for sub-milligram environmental samples in our facility is presented. We describe an optimized hydrolysis procedure now routinely used for the preparation of CO 2 from inorganic samples, a new high-vacuum line dedicated to small sample processing (combining sample distillation and graphitization units), as well as a modified graphitization procedure. Although measurements of graphite targets as small …
A Cremated Bone Intercomparison Study
It is now almost 10 yr since radiocarbon dating of cremated bone was first developed using the small carbonate component contained within the hydroxyapatite-based inorganic fraction. Currently, a significant number of 14 C laboratories date cremated bone as part of their routine dating service. As a general investigation of cremated bone dating since this initial development, a small, cremated bone intercomparison study took place in 2005, involv…
Influence of Mollusk Species on Marine ΔR Determinations
Radiocarbon ages were measured on replicate samples of burnt grain and 5 mollusk species collected from a single sealed layer at an archaeological site (Hornish Point) on the west coast of South Uist, Scotland. The aim was to examine the impact of using different mollusk species on ΔR determinations that are calculated using the paired terrestrial/marine sample approach. The mollusk species examined inhabit a range of environments and utilize a v…
Progress in AMS Target Production of Sub-Milligram Samples at the Nerc Radiocarbon Laboratory
Recent progress in graphite target production for sub-milligram environmental samples in our facility is presented. We describe an optimized hydrolysis procedure now routinely used for the preparation of CO 2 from inorganic samples, a new high-vacuum line dedicated to small sample processing (combining sample distillation and graphitization units), as well as a modified graphitization procedure. Although measurements of graphite targets as small …
Cosmogenic 10 Be and 26 Al ages of Holocene moraines in southern Norway I
Cosmogenic nuclide dating ( 10 Be and 26 Al) is applied to boulders on two moraine ridges at the type-site of the early-Holocene Erdalen Event, southern Norway, dated previously using radiocarbon. Quartz-rich rock samples yielded 10 Be age estimates between 9.8 ± 1.2 and 10.1 ± 1.1 ka (external uncertainties, ± 1σ), with an average of 9.95 ka. These age estimates are statistically indistinguishable from the independent radiocarbon age estimate. 2…
Influence of Mollusk Species on Marine ΔR Determinations
Radiocarbon ages were measured on replicate samples of burnt grain and 5 mollusk species collected from a single sealed layer at an archaeological site (Hornish Point) on the west coast of South Uist, Scotland. The aim was to examine the impact of using different mollusk species on ΔR determinations that are calculated using the paired terrestrial/marine sample approach. The mollusk species examined inhabit a range of environments and utilize a v…
Progress in AMS Target Production of Sub-Milligram Samples at the Nerc Radiocarbon Laboratory
Recent progress in graphite target production for sub-milligram environmental samples in our facility is presented. We describe an optimized hydrolysis procedure now routinely used for the preparation of CO 2 from inorganic samples, a new high-vacuum line dedicated to small sample processing (combining sample distillation and graphitization units), as well as a modified graphitization procedure. Although measurements of graphite targets as small …
The use of ‘bomb spike’ calibration and high-precision AMS 14 C analyses to date salt-marsh sediments deposited during the past three centuries
A combination of ‘bomb spike’ calibration and conventional calibration of AMS 14 C dating has been used to determine a detailed age-depth model for a 1-m sediment section collected from a salt marsh in Poole Harbour, southern England. These data were compared with the chronology obtained from 210 Pb analysis and 137 Cs age markers. We report post bomb values of over 1.46 F 14 C (> 146% modern 14 C), and both the rising and falling limbs of the at…
A Cremated Bone Intercomparison Study
It is now almost 10 yr since radiocarbon dating of cremated bone was first developed using the small carbonate component contained within the hydroxyapatite-based inorganic fraction. Currently, a significant number of 14 C laboratories date cremated bone as part of their routine dating service. As a general investigation of cremated bone dating since this initial development, a small, cremated bone intercomparison study took place in 2005, involv…
Investigation into Background Levels of Small Organic Samples at the Nerc Radiocarbon Laboratory
Recent progress in preparation/combustion of submilligram organic samples at our laboratories is presented. Routine methods had to be modified/refined to achieve acceptable and consistent procedural blanks for organic samples smaller than 1000 μg C. A description of the process leading to a modified combustion method for smaller organic samples is given in detail. In addition to analyzing different background materials, the influence of different…
Cosmogenic 10 Be and 26 Al ages of Holocene moraines in southern Norway I
Cosmogenic nuclide dating ( 10 Be and 26 Al) is applied to boulders on two moraine ridges at the type-site of the early-Holocene Erdalen Event, southern Norway, dated previously using radiocarbon. Quartz-rich rock samples yielded 10 Be age estimates between 9.8 ± 1.2 and 10.1 ± 1.1 ka (external uncertainties, ± 1σ), with an average of 9.95 ka. These age estimates are statistically indistinguishable from the independent radiocarbon age estimate. 2…
Radiocarbon Dating of Fugendake Volcano in Unzen, SW Japan
This article presents new radiocarbon ages for the lavas, pyroclastic flow, and lahar deposits that originated from the Fugendake and Mayuyama volcanoes of the Younger Unzen Volcano, SW Japan. Nine charcoal samples were collected from the lavas and pyroclastic flow deposits, and 17 soil samples from the underlying volcanic-related products. This data set, together with previously published ages (thermoluminescence, K-Ar, fission track, and 14 C),…
Direct radiocarbon ( 14 C) analysis of methane using positive ion mass spectrometry
The reduction of anthropogenic methane emissions is a priority due to its potent global warming potential. Radiocarbon ( 14 C) can distinguish between methane from natural biogenic and fossil fuel sources, however, the analysis of methane 14 C by conventional accelerator mass spectrometry (AMS) techniques is demanding. At SUERC, a prototype positive ion mass spectrometer (PIMS) is set up to directly analyze 14 C in methane with minimal sample pre…
Radiocarbon dating (7 obras) · Geology (6 obras) · Archaeology and ancient environmental studies (5 obras) · Geology and Paleoclimatology Research (4 obras) · Carbon fibers (3 obras) · Geography (3 obras) · Materials Science (3 obras) · Paleontology (3 obras) · Accelerator mass spectrometry (2 obras) · Archaeology (2 obras)