The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform
Keith Barber - One of the best experts on this subject based on the ideXlab platform.
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New Holocene tephras and a Proxy Climate Record from a blanket mire in northern Skye, Scotland
Journal of Quaternary Science, 2001Co-Authors: Peter G. Langdon, Keith BarberAbstract:Four Holocene tephras of Icelandic origin have been identified and geochemically characterised from a water shedding blanket peat sequence on the Trotternish ridge, Isle of Skye, Scotland. Geochemical characterisation of the shards propose the Glen Garry tephra to be present, a tephra layer of Hekla origin incorporating shards from Hekla-4, as well as two new tephras dated by interpolation from a radiocarbon based chronology to ca. 830 cal. yr BP and ca. 2340 cal. yr BP. The new historic tephra has an ambiguous geochemistry and therefore has not been correlated with other known Icelandic historic tephras. The new prehistoric tephra is suggested as originating from the Snaefellsj ¨ okull volcano in northwest Iceland and forms an important stratigraphical marker in this Holocene sequence. A Proxy Climate Record has been derived from humification analyses of the peat, which compares well with other regional palaeoclimatic reconstructions, as well as enabling correlations based on tephra geochemical linkages between sites and climatic Records at precise times in the past
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A replicated 3000 yr Proxy‐Climate Record from Coom Rigg Moss and Felecia Moss, the Border Mires, northern England
Journal of Quaternary Science, 1999Co-Authors: Dmitri Mauquoy, Keith BarberAbstract:Quantitative plant macrofossil and colorimetric humification analyses have been used to reconstruct Proxy-Climate from two paired ombrotrophic bogs in northern England (Coom Rigg Moss and Felecia Moss). Detrended correspondence analysis was used to transform the raw floral data into indices of mire surface wetness. The chronology of each peat profile was determined by radiocarbon assay, supported by pollen correlations. Palaeoclimatic reconstructions have been made by linking documented historical changes in Climate, and other Proxy-Climate Records, to those inferred from the sites investigated in the study region. Both sites contain a sensitive palaeoclimatic Record, as ten periods of increased effective precipitation have been detected between ca. cal. ad 1770–1800, ad 1400–1470, ad 1110–1260, ad 920–1060, ad 550–670, ad 210–360, 30 bc to ad 80, 180–130 bc, 590–520 bc and 760–710 bc. Copyright © 1999 John Wiley & Sons, Ltd.
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Replicability and variability of the recent macrofossil and Proxy‐Climate Record from raised bogs: field stratigraphy and macrofossil data from Bolton Fell Moss and Walton Moss, Cumbria, England
Journal of Quaternary Science, 1998Co-Authors: Keith Barber, Dmitri Mauquoy, Paul D.m. Hughes, Lisa Dumayne-peaty, Rob ScaifeAbstract:Replication of results is a basic tenet of science, but in palaeoecology this is very time-consuming and the ‘signal’ is subject to ‘noise’. The derivation of Proxy-Climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed. Now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles. Ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes, which are also similar to previous profiles from the same sites. It is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest. Recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed. © 1998 John Wiley & Sons, Ltd.
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A 5500-year Proxy-Climate and vegetation Record from blanket mire at Talla Moss, Borders, Scotland
The Holocene, 1997Co-Authors: Frank M. Chambers, Keith Barber, Darrel Maddy, J S BrewAbstract:A monolith of peat taken from an upland blanket mire at Talla Moss, southern Scotland, was sub jected to peat humification and pollen analyses to produce both a Proxy-Climate Record and a vegetational history covering the last 5500 years. While the peat showed little visible stratigraphy, with no intimation of major peat humification changes, colorimetric data indicate a markedly oscillatory Climate Record, which is apparently largely independent of, or out of phase with, major vegetational changes. The raw data imply particular wet shifts in Climate at c. 3455 BP, c. 2600 BP, c. 1930 BP, c. 1095 BP, with a markedly wet (or cool and wet) episode commencing at c. 540 BP. (These are central age estimates, and should not be regarded as precise dates for the inferred Climate shifts.) Other wet shifts apparently date from c. 3070 BP, c. 2265 BP and c. 1700 BP, although the first of these corresponds with pollen evidence for significant prehistoric human activity in the locality. Spectral analysis of the peat h...
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A sensitive high-resolution Record of late Holocene climatic change from a raised bog in northern England:
The Holocene, 1994Co-Authors: Keith Barber, Frank M. Chambers, D Maddy, Rob Stoneman, J S BrewAbstract:Proxy-climatic data in the form of plant macrofossils have been analysed from a 5 m core from Bolton Fell Moss, Cumbria, UK. Detailed analysis of peat from the upper 50 cm of this core is used to demonstrate a strong correlation between changes in the relative proportion of taxa and known climatic changes over the last 1000 years. The Record of changes in bog vegetation contained within the peat profile is used to reconstruct changes in bog-surface wetness for the latter half of the Holocene. As bog- surface wetness is directly controlled by the prevailing climatic conditions, this reconstruction can be viewed as a Proxy-Climate Record. Twelve radiocarbon age estimates on the 5m core suggest that between 50 and 500 cm peat accumulated at a relatively constant rate of 12.4 yr cm-1 . The regular sampling intervals thus provide a time series of past bog-surface wetness; spectral analyses of this series indicates that wetness changes are cyclic, with a ca. 800 year periodicity.
Dmitri Mauquoy - One of the best experts on this subject based on the ideXlab platform.
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a replicated 3000 yr Proxy Climate Record from coom rigg moss and felecia moss the border mires northern england
Journal of Quaternary Science, 1999Co-Authors: Dmitri Mauquoy, K E BarberAbstract:Quantitative plant macrofossil and colorimetric humification analyses have been used to reconstruct Proxy-Climate from two paired ombrotrophic bogs in northern England (Coom Rigg Moss and Felecia Moss). Detrended correspondence analysis was used to transform the raw floral data into indices of mire surface wetness. The chronology of each peat profile was determined by radiocarbon assay, supported by pollen correlations. Palaeoclimatic reconstructions have been made by linking documented historical changes in Climate, and other Proxy-Climate Records, to those inferred from the sites investigated in the study region. Both sites contain a sensitive palaeoclimatic Record, as ten periods of increased effective precipitation have been detected between ca. cal. ad 1770–1800, ad 1400–1470, ad 1110–1260, ad 920–1060, ad 550–670, ad 210–360, 30 bc to ad 80, 180–130 bc, 590–520 bc and 760–710 bc. Copyright © 1999 John Wiley & Sons, Ltd.
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A replicated 3000 yr Proxy‐Climate Record from Coom Rigg Moss and Felecia Moss, the Border Mires, northern England
Journal of Quaternary Science, 1999Co-Authors: Dmitri Mauquoy, Keith BarberAbstract:Quantitative plant macrofossil and colorimetric humification analyses have been used to reconstruct Proxy-Climate from two paired ombrotrophic bogs in northern England (Coom Rigg Moss and Felecia Moss). Detrended correspondence analysis was used to transform the raw floral data into indices of mire surface wetness. The chronology of each peat profile was determined by radiocarbon assay, supported by pollen correlations. Palaeoclimatic reconstructions have been made by linking documented historical changes in Climate, and other Proxy-Climate Records, to those inferred from the sites investigated in the study region. Both sites contain a sensitive palaeoclimatic Record, as ten periods of increased effective precipitation have been detected between ca. cal. ad 1770–1800, ad 1400–1470, ad 1110–1260, ad 920–1060, ad 550–670, ad 210–360, 30 bc to ad 80, 180–130 bc, 590–520 bc and 760–710 bc. Copyright © 1999 John Wiley & Sons, Ltd.
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replicability and variability of the recent macrofossil and Proxy Climate Record from raised bogs field stratigraphy and macrofossil data from bolton fell moss and walton moss cumbria england
Journal of Quaternary Science, 1998Co-Authors: K E Barber, Dmitri Mauquoy, P D M Hughes, Lisa Dumaynepeaty, Rob ScaifeAbstract:Replication of results is a basic tenet of science, but in palaeoecology this is very time-consuming and the ‘signal’ is subject to ‘noise’. The derivation of Proxy-Climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed. Now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles. Ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes, which are also similar to previous profiles from the same sites. It is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest. Recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed. © 1998 John Wiley & Sons, Ltd.
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Replicability and variability of the recent macrofossil and Proxy‐Climate Record from raised bogs: field stratigraphy and macrofossil data from Bolton Fell Moss and Walton Moss, Cumbria, England
Journal of Quaternary Science, 1998Co-Authors: Keith Barber, Dmitri Mauquoy, Paul D.m. Hughes, Lisa Dumayne-peaty, Rob ScaifeAbstract:Replication of results is a basic tenet of science, but in palaeoecology this is very time-consuming and the ‘signal’ is subject to ‘noise’. The derivation of Proxy-Climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed. Now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles. Ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes, which are also similar to previous profiles from the same sites. It is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest. Recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed. © 1998 John Wiley & Sons, Ltd.
K E Barber - One of the best experts on this subject based on the ideXlab platform.
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a 7500 year peat based palaeoclimatic reconstruction and evidence for an 1100 year cyclicity in bog surface wetness from temple hill moss pentland hills southeast scotland
Quaternary Science Reviews, 2003Co-Authors: Peter G. Langdon, K E Barber, P D M HughesAbstract:Analyses of plant macrofossils, peat humification and testate amoebae were used to reconstruct a Proxy Climate Record spanning the last 7500 years from an ombrotrophic bog, Temple Hill Moss, in southeast Scotland. The plant macrofossil data were subjected to detrended correspondence analysis (DCA) which modelled effectively the significant wet shifts within the Record. A mean water table depth transfer function was applied to the testate amoebae data to provide quantifiable changes. The three Proxy Records show coherent phase changes which are interpreted as variability in past effective precipitation. Two tephra horizons (Glen Garry and Lairg A) were used in conjunction with radiocarbon dates to construct an age/depth model, producing a robust geochronology from which a time series was calculated. The palaeoclimatic reconstruction identified major wet shifts throughout the Holocene, with specific events occurring around cal. 6650, 5850, 5300, 4500, 3850, 3400, 2800–2450, 1450–1350 and 250–150 BP. Spectral analysis of the plant macrofossil DCA and colorimetric humification data produced a millennial scale periodicity of 1100 years. The same periodicity has also been found in a palaeoclimatic reconstruction from a site in Cumbria (Walton Moss), and may be linked with millennial scale periodicities found in oceanic palaeoclimatic Records.
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a replicated 3000 yr Proxy Climate Record from coom rigg moss and felecia moss the border mires northern england
Journal of Quaternary Science, 1999Co-Authors: Dmitri Mauquoy, K E BarberAbstract:Quantitative plant macrofossil and colorimetric humification analyses have been used to reconstruct Proxy-Climate from two paired ombrotrophic bogs in northern England (Coom Rigg Moss and Felecia Moss). Detrended correspondence analysis was used to transform the raw floral data into indices of mire surface wetness. The chronology of each peat profile was determined by radiocarbon assay, supported by pollen correlations. Palaeoclimatic reconstructions have been made by linking documented historical changes in Climate, and other Proxy-Climate Records, to those inferred from the sites investigated in the study region. Both sites contain a sensitive palaeoclimatic Record, as ten periods of increased effective precipitation have been detected between ca. cal. ad 1770–1800, ad 1400–1470, ad 1110–1260, ad 920–1060, ad 550–670, ad 210–360, 30 bc to ad 80, 180–130 bc, 590–520 bc and 760–710 bc. Copyright © 1999 John Wiley & Sons, Ltd.
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replicability and variability of the recent macrofossil and Proxy Climate Record from raised bogs field stratigraphy and macrofossil data from bolton fell moss and walton moss cumbria england
Journal of Quaternary Science, 1998Co-Authors: K E Barber, Dmitri Mauquoy, P D M Hughes, Lisa Dumaynepeaty, Rob ScaifeAbstract:Replication of results is a basic tenet of science, but in palaeoecology this is very time-consuming and the ‘signal’ is subject to ‘noise’. The derivation of Proxy-Climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed. Now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles. Ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes, which are also similar to previous profiles from the same sites. It is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest. Recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed. © 1998 John Wiley & Sons, Ltd.
Rob Scaife - One of the best experts on this subject based on the ideXlab platform.
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replicability and variability of the recent macrofossil and Proxy Climate Record from raised bogs field stratigraphy and macrofossil data from bolton fell moss and walton moss cumbria england
Journal of Quaternary Science, 1998Co-Authors: K E Barber, Dmitri Mauquoy, P D M Hughes, Lisa Dumaynepeaty, Rob ScaifeAbstract:Replication of results is a basic tenet of science, but in palaeoecology this is very time-consuming and the ‘signal’ is subject to ‘noise’. The derivation of Proxy-Climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed. Now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles. Ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes, which are also similar to previous profiles from the same sites. It is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest. Recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed. © 1998 John Wiley & Sons, Ltd.
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Replicability and variability of the recent macrofossil and Proxy‐Climate Record from raised bogs: field stratigraphy and macrofossil data from Bolton Fell Moss and Walton Moss, Cumbria, England
Journal of Quaternary Science, 1998Co-Authors: Keith Barber, Dmitri Mauquoy, Paul D.m. Hughes, Lisa Dumayne-peaty, Rob ScaifeAbstract:Replication of results is a basic tenet of science, but in palaeoecology this is very time-consuming and the ‘signal’ is subject to ‘noise’. The derivation of Proxy-Climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed. Now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles. Ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes, which are also similar to previous profiles from the same sites. It is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest. Recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed. © 1998 John Wiley & Sons, Ltd.
Philip L. Gibbard - One of the best experts on this subject based on the ideXlab platform.
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Formal definition and dating of the GSSP (Global Stratotype Section and Point) for the base of the Holocene using the Greenland NGRIP ice core, and selected auxiliary Records
Journal of Quaternary Science, 2009Co-Authors: Mike Walker, Philip L. Gibbard, J. John Lowe, Wim Z Hoek, Sune Olander Rasmussen, Jørgen Peder Steffensen, John T Andrews, Sigfus J Johnsen, Trevor Popp, Svante BjorckAbstract:The Greenland ice core from NorthGRIP (NGRIP) contains a Proxy Climate Record across the Pleistocene-Holocene boundary of unprecedented clarity and resolution. Analysis of an array of physical and chemical parameters within the ice enables the base of the Holocene, as reflected in the first signs of climatic warming at the end of the Younger Dryas/Greenland Stadial 1 cold phase, to be located with a high degree of precision. This climatic event is most clearly reflected in an abrupt shift in deuterium excess values, accompanied by more gradual changes in d 18 O, dust concentration, a range of chemical species, and annual layer thickness. A timescale based on multi-parameter annual layer counting provides an age of 11 700 calendar yr b2 k (before AD 2000) for the base of the Holocene, with a maximum counting error of 99 yr. A proposal that an archived core from this unique sequence should constitute the Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period) has been ratified by the International Union of Geological Sciences. Five auxiliary stratotypes for the Pleistocene-Holocene boundary have also been recognised. Copyright # 2008 John Wiley & Sons, Ltd.
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The Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period) in the NGRIP ice core
Episodes, 2008Co-Authors: Mike Walker, Philip L. Gibbard, J. John Lowe, Wim Z Hoek, Sune Olander Rasmussen, Jørgen Peder Steffensen, John T Andrews, Sigfus J Johnsen, Trevor Popp, Svante BjorckAbstract:The Greenland ice core from NorthGRIP (NGRIP) contains a Proxy Climate Record across the Pleistocene-Holocene boundary of unprecedented clarity and resolution. Analysis of an array of physical and chemical parameters within the ice enables the base of the Holocene, as reflected in the first signs of climatic warming at the end of the Younger Dryas/Greenland Stadial 1 cold phase, to be located with a high degree of precision. This climatic event is most clearly reflected in an. abrupt shaft in deuterium excess values, accompanied by more gradual changes in delta O-18, dust concentration, a range of chemical species, and annual layer thickness. A timescale based on multi-parameter annual layer counting provides an age of 11,700 yr b2k (before AD2000) for the base of the Holocene, with, an estimated 2 sigma uncertainty of 99 yr: It is proposed that an archived core from this unique sequence should constitute the Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period).
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Definition of a Global Stratotype Section and Point (GSSP) for the Base of the Upper (Late) Pleistocene Subseries (Quaternary System/Period)
Episodes, 2008Co-Authors: Thomas Litt, Philip L. GibbardAbstract:Following the precedence already established during the INQUA Congress in 1932, the Middle/Upper (Late) Pleistocene boundary is defined at the base of the Last Interglacial, the Eemian Stage. It is proposed that a high-resolution core sequence from the Amsterdam Terminal (the Eemian Stage parastratotype) should constitute the Global Stratotype Section and Point (GSSP) for the base of the Upper (Late) Pleistocene Subseries (Quaternary System/Period). The core contains a Proxy Climate Record across the Middle/Upper (Late) Pleistocene boundary as indicated by different biotic and abiotic parameters reflecting the first signs of Climate warming at the end of the Saalian cold Stage. For the beginning of the Eemian Stage in Europe, the date of 127.2 ka from the varved-dated Record of Monticchio in Italy can be taken as the best estimate of age.
