<p&amp... more <p>The arrival of the great Maori waka and the settlement of New Zealand some seven or eight hundred years ago are described in oral history, but details of exactly when and how colonisation occurred are undocumented. Radiocarbon dating of early archaeological sites is particularly problematic, due to the inbuilt age of datable materials, and non-linearity and ambiguity in the calibration of measurements to calendar dates. Hangi stones, used as heat retainers in traditional Maori earth ovens, hold thermoremanent records of Earth’s magnetic field at the time of their last cooling. Matching the directions of these magnetizations to established reference curves provides alternative, archaeomagnetic, estimates of age. Our results cover the past 700 years, with a cluster of dates between 1500 and 1600 AD, from both North and South Islands, but none earlier than 1300 AD, thus supporting a model of rapid coordinated migration around that time. Archaeointensity data have been obtained from sixteen distinct archaeological features, including twelve hangi from eight sites, and from them the first archaeointensity record for New Zealand has been constructed. To this has been added other archaeointensity and palaeointensity data from the SW Pacific region and virtual axial dipole moments (VADMs) have been plotted. This plot outlines steady VADM values of about 8 x10<sup>22</sup> Am<sup>2</sup> from 1000-1300 AD, and 9.5 x10<sup>22</sup> Am<sup>2</sup> from 1500 AD to the present, with an intervening sharp peak in the early 15<sup>th</sup> century when the VADM reached about 13 x10<sup>22</sup> Am<sup>2</sup>. This peak bears many similarities to archaeomagnetic “jerks” and “spikes” in northern hemisphere records from the first millennia BC and AD. However, it is the first such feature to be found in the southern hemisphere at this date, suggesting, in accordance with recent modelling, that it may be a feature of the non-dipole field, associated with rapid growth and decay of an intense flux patch on the core-mantle boundary.</p>
Hangi stones, used to retain heat in traditional Maori earth ovens (hangi), may carry records of ... more Hangi stones, used to retain heat in traditional Maori earth ovens (hangi), may carry records of Earth's magnetic field when they were last used. Sixteen archaeological features, including 12 hangi, from eight sites were sampled and their palaeomagnetic data used to construct the first archaeointensity record for New Zealand, covering the past 700 years. A combination of radiocarbon dating of associated charcoal and archaeomagnetic dating of palaeomagnetic directions was used to obtain a ‘preferred’ date of each palaeointensity. A plot of virtual axial dipole moment (VADM) for the SW Pacific region outlines steady VADM values of about 8 × 1022 A m2 from 1000 to 1300 AD and 9.5 × 1022 A m2 from 1500 AD to the present, with a sharp peak in the early fifteenth century when the VADM reached about 13 × 1022 A m2. This peak bears many similarities to archaeomagnetic ‘jerks’ and ‘spikes’ in Northern Hemisphere records from the first millennia BC and AD. However, it is the first such fe...
ABSTRACT.We present the first radiocarbon dates from previously unrecorded, secondary burials in ... more ABSTRACT.We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Mountains,Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally harvested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a highland burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is concurrent with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom ritual relative to known funerary rituals of the pre- to post-Angkorian periods, and to similar exposed jar and coffin burial rituals in Mainland and Island Southeast Asia
Gauging the effect of 14C-depleted marine foods on radiocarbon ages requires an accurate assessme... more Gauging the effect of 14C-depleted marine foods on radiocarbon ages requires an accurate assessment of the likely proportion of marine foods in the diet. Several factors must be considered, including region-specific δ13C, δ15N and δ34S data values (regional stable isotope values can differ from global averages), temporal variations in δ13C which offset values in modern dietary standards by up to 1.5‰, and that modelling which considers only δ13C may overestimate the contribution of various dietary sources. Here, we compare previous calculations by linear interpolation of δ13C and a complex computer simulation of marine contribution to the diet of inhumations from the SAC archaeological site Watom Island, Papua New Guinea, with the ISOSOURCE mixing model and a revised database of regional dietary sources and their isotopic values, to estimate marine diet contributions and radiocarbon offsets for burials from the SAC site. Though different estimates of marine contribution to diet do not significantly alter previous calibrations of radiocarbon ages for the inhumations, the new ISOSOURCE calculations challenge the idea of excessive exploitation of marine resources and support evidence for arboriculture and horticulture being a major component in Lapita diet.Keywords Watom Island; Lapita; marine offsets; calibration; mixing models; dietary standards
ABSTRACT Smoothed curves are least-squares fitted to three sets of decadal radiocarbon calibratio... more ABSTRACT Smoothed curves are least-squares fitted to three sets of decadal radiocarbon calibration data from New Zealand and British Isles (AD 1725-1935) and western North America (AD 1145-1945). The curves are compared with each other and with a curve previously calculated from New Zealand data (AD 1335-1745). The smoothing procedure results in reduced standard deviations of the curves, but at the expense of time resolution. The comparison shows a variable 14C offset between the northern and southern hemispheres of 0-70 years (Southern Hemisphere older), and a Northern Hemisphere longitudinal variation of -20 to +60 years (British Isles generally older than western North America).
... Titre du document / Document title. Radiocarbon calibration curve variations and their implic... more ... Titre du document / Document title. Radiocarbon calibration curve variations and their implications for the interpretation of New Zealand prehistory. Auteur(s) / Author(s). MCFADGEN BG (1) ; KNOX FB ; COLE TRL ; ... Method. ; Dating. ; Chemical analysis. ; Radiocarbon. ; Population ...
ABSTRACT We Fourier transformed and filtered calibration curve data to compensate for the averagi... more ABSTRACT We Fourier transformed and filtered calibration curve data to compensate for the averaging effect of radiocar-bon-dating sets of adjacent tree rings. A Wiener Filter was also applied to minimize the effects of the counting errors of the dates on the resulting calibration curve and to produce a least-squares curve through the data. The method is illustrated using a short 14C-dated tree-ring sequence from New Zealand to produce a calibration curve at yearly intervals for New Zealand matai (Prumnopitys taxi folia). The resulting curve has a nominal standard error of 10±3 yr, which is ca. half the average stan-dard error of the original raw data.
... Figure 2 Detrended calibration curves from the west coast of North America (Douglas fir), Bri... more ... Figure 2 Detrended calibration curves from the west coast of North America (Douglas fir), British Isles (European oak), and New Zealand (cedar) compared with the Wolf, Sporer, Maunder, and Dalton periods of climatic cooling in the North Atlantic (Masarik and Beer 1999 ...
RefDoc, THE reference in scientific document supply / Refdoc, la référence en fourniture de docum... more RefDoc, THE reference in scientific document supply / Refdoc, la référence en fourniture de documents scientifiques ...
We present the first radiocarbon dates from previously unrecorded, secondary burials in the Carda... more We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Moun- tains, Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally har- vested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a high- land burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is con- current with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom rit- ual relative to known funerary rituals of the pre- to post-Angkorian periods, and to similar exposed jar and coffin burial rituals in Mainland and Island Southeast Asia.
We propose a model for the seismic driving of environmental changes and illustrate it using a cas... more We propose a model for the seismic driving of environmental changes and illustrate it using a case study from New Zealand dated to the 15th Century AD. A "seismic staircase" shows a chronological progression of environmental outcomes that includes tsunami, rock avalanches, vegetation disturbance, rapid coastal dune building, river aggradation, and abandonment of prehistoric coastal settlements. The 15th Century event appears to be unique in the past Millenium and is most notable for its period of rapid coastal dune building. The coincidence of a catastrophic El Niño episode in the mid 15th Century AD may have served to move sediments rapidly through the terrestrial system thus delimiting clearly separate geomorphological after-effects. We contend that seismic driving is a major factor in determining paleoenvironmental change in tectonically active areas during the Holocene and provides the palaeoenvironmental context within which smaller scale events operate.
ABSTRACT Four stranded beach ridge deposits are recognised at Avoca Point, Kaikoura and are consi... more ABSTRACT Four stranded beach ridge deposits are recognised at Avoca Point, Kaikoura and are considered to have been uplifted by earthquakes. An uplift rate of 1.5 mm/year is derived from beach ridge heights and radiocarbon dates. Earthquake uplifts are dated at 1900 years ago (amount unknown), 1400 years ago (1.1 m), 400 years ago (0.8 m), and 200 years ago (1.1 m).Intermittent human occupation, probably for fishing, fowling and scavenging, was located on the actively-growing Beach Ridge C, between the sea and a lagoon. Cultural remains have very probably been mixed with the beach ridge deposits, with naturally stranded shells, and with bones from carcasses stranded by wave action.
Abstract Gauging the effect of14C-depleted marine foods on radiocarbon ages requires an accurate ... more Abstract Gauging the effect of14C-depleted marine foods on radiocarbon ages requires an accurate assessment of the likely proportion of marine foods in the diet. Several factors must be considered, including region-specific δ13C, δ15N and δ34S data values (regional stable ...
<p&amp... more <p>The arrival of the great Maori waka and the settlement of New Zealand some seven or eight hundred years ago are described in oral history, but details of exactly when and how colonisation occurred are undocumented. Radiocarbon dating of early archaeological sites is particularly problematic, due to the inbuilt age of datable materials, and non-linearity and ambiguity in the calibration of measurements to calendar dates. Hangi stones, used as heat retainers in traditional Maori earth ovens, hold thermoremanent records of Earth’s magnetic field at the time of their last cooling. Matching the directions of these magnetizations to established reference curves provides alternative, archaeomagnetic, estimates of age. Our results cover the past 700 years, with a cluster of dates between 1500 and 1600 AD, from both North and South Islands, but none earlier than 1300 AD, thus supporting a model of rapid coordinated migration around that time. Archaeointensity data have been obtained from sixteen distinct archaeological features, including twelve hangi from eight sites, and from them the first archaeointensity record for New Zealand has been constructed. To this has been added other archaeointensity and palaeointensity data from the SW Pacific region and virtual axial dipole moments (VADMs) have been plotted. This plot outlines steady VADM values of about 8 x10<sup>22</sup> Am<sup>2</sup> from 1000-1300 AD, and 9.5 x10<sup>22</sup> Am<sup>2</sup> from 1500 AD to the present, with an intervening sharp peak in the early 15<sup>th</sup> century when the VADM reached about 13 x10<sup>22</sup> Am<sup>2</sup>. This peak bears many similarities to archaeomagnetic “jerks” and “spikes” in northern hemisphere records from the first millennia BC and AD. However, it is the first such feature to be found in the southern hemisphere at this date, suggesting, in accordance with recent modelling, that it may be a feature of the non-dipole field, associated with rapid growth and decay of an intense flux patch on the core-mantle boundary.</p>
Hangi stones, used to retain heat in traditional Maori earth ovens (hangi), may carry records of ... more Hangi stones, used to retain heat in traditional Maori earth ovens (hangi), may carry records of Earth's magnetic field when they were last used. Sixteen archaeological features, including 12 hangi, from eight sites were sampled and their palaeomagnetic data used to construct the first archaeointensity record for New Zealand, covering the past 700 years. A combination of radiocarbon dating of associated charcoal and archaeomagnetic dating of palaeomagnetic directions was used to obtain a ‘preferred’ date of each palaeointensity. A plot of virtual axial dipole moment (VADM) for the SW Pacific region outlines steady VADM values of about 8 × 1022 A m2 from 1000 to 1300 AD and 9.5 × 1022 A m2 from 1500 AD to the present, with a sharp peak in the early fifteenth century when the VADM reached about 13 × 1022 A m2. This peak bears many similarities to archaeomagnetic ‘jerks’ and ‘spikes’ in Northern Hemisphere records from the first millennia BC and AD. However, it is the first such fe...
ABSTRACT.We present the first radiocarbon dates from previously unrecorded, secondary burials in ... more ABSTRACT.We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Mountains,Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally harvested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a highland burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is concurrent with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom ritual relative to known funerary rituals of the pre- to post-Angkorian periods, and to similar exposed jar and coffin burial rituals in Mainland and Island Southeast Asia
Gauging the effect of 14C-depleted marine foods on radiocarbon ages requires an accurate assessme... more Gauging the effect of 14C-depleted marine foods on radiocarbon ages requires an accurate assessment of the likely proportion of marine foods in the diet. Several factors must be considered, including region-specific δ13C, δ15N and δ34S data values (regional stable isotope values can differ from global averages), temporal variations in δ13C which offset values in modern dietary standards by up to 1.5‰, and that modelling which considers only δ13C may overestimate the contribution of various dietary sources. Here, we compare previous calculations by linear interpolation of δ13C and a complex computer simulation of marine contribution to the diet of inhumations from the SAC archaeological site Watom Island, Papua New Guinea, with the ISOSOURCE mixing model and a revised database of regional dietary sources and their isotopic values, to estimate marine diet contributions and radiocarbon offsets for burials from the SAC site. Though different estimates of marine contribution to diet do not significantly alter previous calibrations of radiocarbon ages for the inhumations, the new ISOSOURCE calculations challenge the idea of excessive exploitation of marine resources and support evidence for arboriculture and horticulture being a major component in Lapita diet.Keywords Watom Island; Lapita; marine offsets; calibration; mixing models; dietary standards
ABSTRACT Smoothed curves are least-squares fitted to three sets of decadal radiocarbon calibratio... more ABSTRACT Smoothed curves are least-squares fitted to three sets of decadal radiocarbon calibration data from New Zealand and British Isles (AD 1725-1935) and western North America (AD 1145-1945). The curves are compared with each other and with a curve previously calculated from New Zealand data (AD 1335-1745). The smoothing procedure results in reduced standard deviations of the curves, but at the expense of time resolution. The comparison shows a variable 14C offset between the northern and southern hemispheres of 0-70 years (Southern Hemisphere older), and a Northern Hemisphere longitudinal variation of -20 to +60 years (British Isles generally older than western North America).
... Titre du document / Document title. Radiocarbon calibration curve variations and their implic... more ... Titre du document / Document title. Radiocarbon calibration curve variations and their implications for the interpretation of New Zealand prehistory. Auteur(s) / Author(s). MCFADGEN BG (1) ; KNOX FB ; COLE TRL ; ... Method. ; Dating. ; Chemical analysis. ; Radiocarbon. ; Population ...
ABSTRACT We Fourier transformed and filtered calibration curve data to compensate for the averagi... more ABSTRACT We Fourier transformed and filtered calibration curve data to compensate for the averaging effect of radiocar-bon-dating sets of adjacent tree rings. A Wiener Filter was also applied to minimize the effects of the counting errors of the dates on the resulting calibration curve and to produce a least-squares curve through the data. The method is illustrated using a short 14C-dated tree-ring sequence from New Zealand to produce a calibration curve at yearly intervals for New Zealand matai (Prumnopitys taxi folia). The resulting curve has a nominal standard error of 10±3 yr, which is ca. half the average stan-dard error of the original raw data.
... Figure 2 Detrended calibration curves from the west coast of North America (Douglas fir), Bri... more ... Figure 2 Detrended calibration curves from the west coast of North America (Douglas fir), British Isles (European oak), and New Zealand (cedar) compared with the Wolf, Sporer, Maunder, and Dalton periods of climatic cooling in the North Atlantic (Masarik and Beer 1999 ...
RefDoc, THE reference in scientific document supply / Refdoc, la référence en fourniture de docum... more RefDoc, THE reference in scientific document supply / Refdoc, la référence en fourniture de documents scientifiques ...
We present the first radiocarbon dates from previously unrecorded, secondary burials in the Carda... more We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Moun- tains, Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally har- vested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a high- land burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is con- current with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom rit- ual relative to known funerary rituals of the pre- to post-Angkorian periods, and to similar exposed jar and coffin burial rituals in Mainland and Island Southeast Asia.
We propose a model for the seismic driving of environmental changes and illustrate it using a cas... more We propose a model for the seismic driving of environmental changes and illustrate it using a case study from New Zealand dated to the 15th Century AD. A "seismic staircase" shows a chronological progression of environmental outcomes that includes tsunami, rock avalanches, vegetation disturbance, rapid coastal dune building, river aggradation, and abandonment of prehistoric coastal settlements. The 15th Century event appears to be unique in the past Millenium and is most notable for its period of rapid coastal dune building. The coincidence of a catastrophic El Niño episode in the mid 15th Century AD may have served to move sediments rapidly through the terrestrial system thus delimiting clearly separate geomorphological after-effects. We contend that seismic driving is a major factor in determining paleoenvironmental change in tectonically active areas during the Holocene and provides the palaeoenvironmental context within which smaller scale events operate.
ABSTRACT Four stranded beach ridge deposits are recognised at Avoca Point, Kaikoura and are consi... more ABSTRACT Four stranded beach ridge deposits are recognised at Avoca Point, Kaikoura and are considered to have been uplifted by earthquakes. An uplift rate of 1.5 mm/year is derived from beach ridge heights and radiocarbon dates. Earthquake uplifts are dated at 1900 years ago (amount unknown), 1400 years ago (1.1 m), 400 years ago (0.8 m), and 200 years ago (1.1 m).Intermittent human occupation, probably for fishing, fowling and scavenging, was located on the actively-growing Beach Ridge C, between the sea and a lagoon. Cultural remains have very probably been mixed with the beach ridge deposits, with naturally stranded shells, and with bones from carcasses stranded by wave action.
Abstract Gauging the effect of14C-depleted marine foods on radiocarbon ages requires an accurate ... more Abstract Gauging the effect of14C-depleted marine foods on radiocarbon ages requires an accurate assessment of the likely proportion of marine foods in the diet. Several factors must be considered, including region-specific δ13C, δ15N and δ34S data values (regional stable ...
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Papers by Bruce McFadgen
in Mainland and Island Southeast Asia
(regional stable isotope values can differ from global averages), temporal variations in δ13C which offset values in modern dietary standards by up to 1.5‰, and that modelling which considers only δ13C may overestimate the contribution of various dietary sources. Here, we compare previous calculations by linear interpolation of δ13C and a complex computer simulation of marine contribution to the diet of inhumations from the SAC
archaeological site Watom Island, Papua New Guinea, with the ISOSOURCE mixing model and a revised database of regional dietary sources and their isotopic values, to estimate marine diet contributions and radiocarbon offsets for burials from the SAC site. Though different estimates of marine contribution to diet do not significantly alter previous calibrations of radiocarbon ages for the inhumations, the new ISOSOURCE calculations challenge the idea of excessive exploitation of marine resources and support evidence for arboriculture and horticulture being a major component in Lapita diet.Keywords Watom Island; Lapita; marine offsets; calibration; mixing models; dietary standards
in Mainland and Island Southeast Asia
(regional stable isotope values can differ from global averages), temporal variations in δ13C which offset values in modern dietary standards by up to 1.5‰, and that modelling which considers only δ13C may overestimate the contribution of various dietary sources. Here, we compare previous calculations by linear interpolation of δ13C and a complex computer simulation of marine contribution to the diet of inhumations from the SAC
archaeological site Watom Island, Papua New Guinea, with the ISOSOURCE mixing model and a revised database of regional dietary sources and their isotopic values, to estimate marine diet contributions and radiocarbon offsets for burials from the SAC site. Though different estimates of marine contribution to diet do not significantly alter previous calibrations of radiocarbon ages for the inhumations, the new ISOSOURCE calculations challenge the idea of excessive exploitation of marine resources and support evidence for arboriculture and horticulture being a major component in Lapita diet.Keywords Watom Island; Lapita; marine offsets; calibration; mixing models; dietary standards