An important constraint on the reliability of cosmogenic nuclide exposure dating is the derivatio... more An important constraint on the reliability of cosmogenic nuclide exposure dating is the derivation of tightly controlled production rates. We present a new dataset for 10 Be production rate calibration from Mount Billingen, southern Sweden, the site of the final drainage of the Baltic Ice Lake, an event dated to 11,620 ± 100 cal yr BP. Nine samples of flood-scoured bedrock surfaces and depositional boulders and cobbles unambiguously connected to the drainage event yield a reference 10 Be production rate of 4.09 ± 0.22 atoms g −1 yr −1 for the CRONUS Lm scaling and 3.93 ± 0.21 atoms g −1 yr −1 for the LSD general spallation scaling. We also recalibrate the reference 10 Be production rates for four sites in Norway and combine these with the Billingen results to derive a tightly clustered Scandinavian reference 10 Be production rate of 4.12 ± 0.10 (4.12 ± 0.25 for altitude scaling) atoms g −1 yr −1 for the Lm scaling scheme and 3.96 ± 0.10 (3.96 ± 0.24 for altitude scaling) atoms g −1 yr −1 for the LSD scaling scheme.
A major threat to the Scotch whisky industry is the sale of counterfeit single malt whiskies with... more A major threat to the Scotch whisky industry is the sale of counterfeit single malt whiskies with purported distillation years in the 19th and early- to mid-20th centuries. However, these are often much more recent spirits, distilled in the latter part of the 20th or first part of the 21st centuries. These sales impinge upon the reputation of auction houses, retailers, brand owners and distillers. The atmospheric testing of nuclear weapons in the 1950s and early 1960s has enabled a precise calibration curve to be created, however, there are several reasons why this may not be appropriate for establishing the year of whisky distillation. We have created a 14C calibration curve derived from known-age, single malt whiskies for the period 1950–2015 that enables whisky distilled during the period from 1955 onwards to have the distillation year determined to within 1–3 years for certain periods. However, because of the shape of the curve, two possible age ranges are often possible. The co...
The southern North Sea is a particularly important area for understanding the behaviour of the Br... more The southern North Sea is a particularly important area for understanding the behaviour of the British-Irish Ice Sheet (BIIS) during the last glacial cycle. It preserves a record of the maximum extent of the eastern sector BIIS as well as evidence for multiple different ice flow phases and the dynamic re-organisation of the BIIS. However, to date, the known ice sheet history and geochronology of this region is predominantly derived from onshore geological evidence, and the offshore imprint and dynamic history of the last ice sheet remain largely unknown. Using new data collected by the BRITICE-CHRONO project this paper explores the origin and age of the Dogger Bank; reassesses the extent and age of the glaciogenic deposits across the shallow areas of the North Sea between the Dogger Bank and the north Norfolk coast and; reexamines the dynamic behaviour of the BIIS in the southern North Sea between 30-21.5 ka. Analysing over 540km of sub-bottom profile data and forty vibro-cores, as well as deriving new optically stimulated luminescence and radiocarbon ages to constrain ice sheet history, this paper shows the core of the Dogger Bank to be composed glaciolacustrine sediment deposited between 31.6-25.8 ka. Following its initial formation the western end of the Dogger lake was overridden with ice reaching ~ 54°N where the ice margin is co-incident with the southerly extent of subglacial tills previously mapped as Bolders Bank Fm. Ice override and retreat northwards back across the Dogger lake was rapid and complete by 23.1 ka, but resulted in widespread compressive glaciotectonism of the lake sediments and the formation of thrust moraine complexes and ice marginal deposits on both the southern and northern edges of the newly formed Dogger Bank. Along the northern edge of the bank moraines are on-lapped by later phase glaciolacustrine and marine sediments but do not show evidence of subsequent ice override. The new seismic data supports the previous notion that Dogger Bank is a thrust moraine complex and is a product of ice marginal instability promoted by ice sheet interaction with the Dogger Lake which would have initiated drawdown and provided ideal conditions for the development of a subglacial deforming bed and, hence, flow instability. With the Dogger Bank acting as a positive relief feature, the shallow seafloor to the west and southwest records several later phases of ice advance and retreat as the North Sea Lobe flowed between the Dogger Bank and the Yorkshire/Lincolnshire coasts and reached North Norfolk. New optically stimulated luminescence (OSL) ages from Garrett Hill on outwash below an upper till limit the arrival of the BIIS on the Norfolk coast to 22.8-21.5 ka. Multiple till sheets and chains of moraines on the seafloor north of Norfolk mark dynamic oscillation of the North Sea Lobe margin as it retreated northwards. This pattern of behaviour is broadly synchronous with the terrestrial record of deposition of subglacial, glaciofluvial and glaciolacustrine sediments along the Yorkshire coast which relate to post Dimlington Stadial ice marginal oscillations between after 21.5 ka With respect to forcing mechanisms it is likely that during the early phases of the last glacial maximum (~30-23ka) the interaction between the southern margin of the BIIS and the Dogger Lake was critical in influencing flow instability and rapid ice advance and retreat. Glaciotectonism of the However, during the latter part of the last glacial maximum (22-21 ka) late-phase ice advance in the southern North Sea became restricted to the western side of the Dogger Bank which was a substantial topographic feature by this time. This topographic confinement, in addition to decoupling of the BIIS and the Fennoscandian Ice Sheet (FIS) further north, enabled ice to reach the north Norfolk coast, overprinting the seabed with late-phase tills of the Bolders Bank Fm.
In this paper, we describe improvements to the in situ cosmogenic radiocarbon extraction system a... more In this paper, we describe improvements to the in situ cosmogenic radiocarbon extraction system at SUERC made since 2004, highlighting the factors that potentially control the reduction of analytical variability. We also present new results on system blanks and of measurements of in situ 14C in shielded quartz and a surface quartz sample used at the University of Arizona as an in situ 14C standard (PP-4). The SUERC in situ 14C extraction system was built in 2001 and is based on a combustion technique following the design of the extraction system at the University of Arizona. Our preliminary results suggest that the continuous running of the extraction system and the monitoring of gas collecting time and of the temperature of the cryogenic traps used in the gas cleaning steps are key to maintaining low and stable system blanks. Our latest average system blank is 2.02 ± 0.23 x 105 14C atoms. This is consistent with those recently published by the University of Arizona and ETH in situ ...
The identification of tephra within varved deposits of a former ice-dammed lake that 11 existed i... more The identification of tephra within varved deposits of a former ice-dammed lake that 11 existed in Scotland during the Younger Dryas provides an opportunity to calibrate 12 10 Be production rates using previously published 10 Be concentrations from the lake 13 shoreline and independently derived ages for the tephra's derived from the Greenland 14 Ice Core records. The best-estimate ages of the tephras yield indistinguishable 10 Be 15 production rate values for spallation with an average value of 4.26 ± 0.21 atoms g-1 a-1 16 using the 'Lm' scaling scheme. These values are in best agreement with the most 17 proximal reference 10 Be production rate from Norway.
The sustainable use of soils represents one of the key challenges that society faces. Glacial sed... more The sustainable use of soils represents one of the key challenges that society faces. Glacial sediments (tills and moraines) form the parent material of soils in many parts of the northern hemisphere but little is known about the histories of these soils. Several methods of estimating soil erosion exist but these have limitations, mainly in that they are unable to
We describe improvements to the in situ cosmogenic C-14 extraction system at SUERC made since 200... more We describe improvements to the in situ cosmogenic C-14 extraction system at SUERC made since 2004 and present new in situ cosmogenic C-14 and Be-10 data testing whether depth-profiles of these nuclides can be used to determine amounts and timing of erosion on a soil formed on a Younger Dryas moraine in Scotland. The SUERC in situ C-14 extraction system
Enlighten-Research publications by members of the University of Glasgow http://eprints.gla.ac.uk ... more Enlighten-Research publications by members of the University of Glasgow http://eprints.gla.ac.uk Lake Store Finnsjøen-a key for understanding Late-Glacial/early Holocene vegetation and ice sheet dynamics in the central Scandes Mountains
ABSTRACT The present study aims at testing the possibility of using the in-situ cosmogenic burial... more ABSTRACT The present study aims at testing the possibility of using the in-situ cosmogenic burial dating technique on deltaic deposits. The sequence analyzed is exposed along the Ligurian coast (north-west Italy) and is made of proximal marine and continental deposits previously considered Pliocene or Plio-Quaternary in age. In the study area two allostratigraphic units were recognized. The lower unit represents the evolution of a small coarse-grained delta developed in a fjord or embayment environment. The coarsening / shallowing upward trend observed within the sections, from bottom to top, suggests that the delta prograded rapidly in the landward portion of the canyon placed opposite to the paleo-river outlet. Within the deltaic sequence the transgressive and highstand system tracts were recognized. The unit 2 is composed by several alluvial fan systems deposited in small incised valleys developed within the previously, uplifted deltaic deposits and successively incised by a braided river system. In-situ produced cosmogenic nuclides were used in order to date the age of the deposition of the deltaic deposits. Results suggest that the studied deltaic sediments belonging to the unit 1 were deposited between 1,300,000 and 200,000 year ago thus during the Lower to Middle Pleistocene, whereas the unit 2 was deposited during the Middle Pleistocene as a consequence of a tectonically driven uplift phase. Furthermore samples collected within the prograding part of the delta show the higher denudation rates. The obtained results demonstrate that burial ages and related erosion rates inferred from cosmogenic nuclides concentrations can be considered as a very useful tool to reconstruct the sea level changes over the past 1 million year.
ABSTRACT The widely accepted concept that ice sheet erosion is both pervasive and highly signific... more ABSTRACT The widely accepted concept that ice sheet erosion is both pervasive and highly significant in landscape modification in glaciated areas has been tested in northern Sweden using field mapping and cosmogenic nuclide techniques. The following lines of evidence suggest that this concept does not apply to recent glaciations in this region: (i) relict portions of mountainous landscapes have been unmodified by glacial erosion for at least 845 kyr, despite multiple glaciations. We base this estimate on the contrast between in situ cosmogenic 10Be and 26Al concentrations from erratics on relict surfaces and glacially eroded bedrock adjacent to these surfaces (consistent last deglaciation exposure ages, ˜8--13 kyr), compared to exposure ages of 34 kyr to 61 kyr on bedrock surfaces in these same relict areas, demonstrating that these areas were preserved through multiple glacial cycles. (ii) relict lowland landscape elements, tors, have been essentially unmodified by glacial erosion for at least 605 kyr. We base this estimate on apparent 10Be and 26Al exposure ages of tor summit bedrock surfaces ranging between 79 and 37 ka, in an area deglaciated at 11 ka, suggesting that these relict landforms have survived glaciation with little or no erosion. (iii) areas of apparent significant glacial modification have undergone limited erosion during the last glacial cycle. Cosmogenic 10Be and 36Cl data from one glacial corridor and adjacent relict surfaces match temporal and spatial variations of glacial erosion that were suggested by geomorphological mapping. However, glacial erosion estimates in what appear to be heavily scoured areas indicate erosion of only ˜2 ± 0.4 m of bedrock during the last glaciation, based on cosmogenic nuclide inheritance. Although surprisingly low, this rock loss depth does yield an erosion rate for the glacial corridor that is at least an order of magnitude higher than maximum erosion rates over relict surfaces, which typically are 1--2 m/Ma. These results indicate that the overall modification produced by ice sheets along glacial corridors may either be more restricted than previously thought, or occurred preferentially during earlier Quaternary glacial periods. Erosion over relict surfaces, which comprises about 20% of the area in the northern Swedish mountains and most of the eastern mountain foreland, has been negligible, and these relict areas need to be accounted for as frozen bed patches in basal boundary conditions for ice sheet and landscape development models.
An important constraint on the reliability of cosmogenic nuclide exposure dating is the derivatio... more An important constraint on the reliability of cosmogenic nuclide exposure dating is the derivation of tightly controlled production rates. We present a new dataset for 10 Be production rate calibration from Mount Billingen, southern Sweden, the site of the final drainage of the Baltic Ice Lake, an event dated to 11,620 ± 100 cal yr BP. Nine samples of flood-scoured bedrock surfaces and depositional boulders and cobbles unambiguously connected to the drainage event yield a reference 10 Be production rate of 4.09 ± 0.22 atoms g −1 yr −1 for the CRONUS Lm scaling and 3.93 ± 0.21 atoms g −1 yr −1 for the LSD general spallation scaling. We also recalibrate the reference 10 Be production rates for four sites in Norway and combine these with the Billingen results to derive a tightly clustered Scandinavian reference 10 Be production rate of 4.12 ± 0.10 (4.12 ± 0.25 for altitude scaling) atoms g −1 yr −1 for the Lm scaling scheme and 3.96 ± 0.10 (3.96 ± 0.24 for altitude scaling) atoms g −1 yr −1 for the LSD scaling scheme.
A major threat to the Scotch whisky industry is the sale of counterfeit single malt whiskies with... more A major threat to the Scotch whisky industry is the sale of counterfeit single malt whiskies with purported distillation years in the 19th and early- to mid-20th centuries. However, these are often much more recent spirits, distilled in the latter part of the 20th or first part of the 21st centuries. These sales impinge upon the reputation of auction houses, retailers, brand owners and distillers. The atmospheric testing of nuclear weapons in the 1950s and early 1960s has enabled a precise calibration curve to be created, however, there are several reasons why this may not be appropriate for establishing the year of whisky distillation. We have created a 14C calibration curve derived from known-age, single malt whiskies for the period 1950–2015 that enables whisky distilled during the period from 1955 onwards to have the distillation year determined to within 1–3 years for certain periods. However, because of the shape of the curve, two possible age ranges are often possible. The co...
The southern North Sea is a particularly important area for understanding the behaviour of the Br... more The southern North Sea is a particularly important area for understanding the behaviour of the British-Irish Ice Sheet (BIIS) during the last glacial cycle. It preserves a record of the maximum extent of the eastern sector BIIS as well as evidence for multiple different ice flow phases and the dynamic re-organisation of the BIIS. However, to date, the known ice sheet history and geochronology of this region is predominantly derived from onshore geological evidence, and the offshore imprint and dynamic history of the last ice sheet remain largely unknown. Using new data collected by the BRITICE-CHRONO project this paper explores the origin and age of the Dogger Bank; reassesses the extent and age of the glaciogenic deposits across the shallow areas of the North Sea between the Dogger Bank and the north Norfolk coast and; reexamines the dynamic behaviour of the BIIS in the southern North Sea between 30-21.5 ka. Analysing over 540km of sub-bottom profile data and forty vibro-cores, as well as deriving new optically stimulated luminescence and radiocarbon ages to constrain ice sheet history, this paper shows the core of the Dogger Bank to be composed glaciolacustrine sediment deposited between 31.6-25.8 ka. Following its initial formation the western end of the Dogger lake was overridden with ice reaching ~ 54°N where the ice margin is co-incident with the southerly extent of subglacial tills previously mapped as Bolders Bank Fm. Ice override and retreat northwards back across the Dogger lake was rapid and complete by 23.1 ka, but resulted in widespread compressive glaciotectonism of the lake sediments and the formation of thrust moraine complexes and ice marginal deposits on both the southern and northern edges of the newly formed Dogger Bank. Along the northern edge of the bank moraines are on-lapped by later phase glaciolacustrine and marine sediments but do not show evidence of subsequent ice override. The new seismic data supports the previous notion that Dogger Bank is a thrust moraine complex and is a product of ice marginal instability promoted by ice sheet interaction with the Dogger Lake which would have initiated drawdown and provided ideal conditions for the development of a subglacial deforming bed and, hence, flow instability. With the Dogger Bank acting as a positive relief feature, the shallow seafloor to the west and southwest records several later phases of ice advance and retreat as the North Sea Lobe flowed between the Dogger Bank and the Yorkshire/Lincolnshire coasts and reached North Norfolk. New optically stimulated luminescence (OSL) ages from Garrett Hill on outwash below an upper till limit the arrival of the BIIS on the Norfolk coast to 22.8-21.5 ka. Multiple till sheets and chains of moraines on the seafloor north of Norfolk mark dynamic oscillation of the North Sea Lobe margin as it retreated northwards. This pattern of behaviour is broadly synchronous with the terrestrial record of deposition of subglacial, glaciofluvial and glaciolacustrine sediments along the Yorkshire coast which relate to post Dimlington Stadial ice marginal oscillations between after 21.5 ka With respect to forcing mechanisms it is likely that during the early phases of the last glacial maximum (~30-23ka) the interaction between the southern margin of the BIIS and the Dogger Lake was critical in influencing flow instability and rapid ice advance and retreat. Glaciotectonism of the However, during the latter part of the last glacial maximum (22-21 ka) late-phase ice advance in the southern North Sea became restricted to the western side of the Dogger Bank which was a substantial topographic feature by this time. This topographic confinement, in addition to decoupling of the BIIS and the Fennoscandian Ice Sheet (FIS) further north, enabled ice to reach the north Norfolk coast, overprinting the seabed with late-phase tills of the Bolders Bank Fm.
In this paper, we describe improvements to the in situ cosmogenic radiocarbon extraction system a... more In this paper, we describe improvements to the in situ cosmogenic radiocarbon extraction system at SUERC made since 2004, highlighting the factors that potentially control the reduction of analytical variability. We also present new results on system blanks and of measurements of in situ 14C in shielded quartz and a surface quartz sample used at the University of Arizona as an in situ 14C standard (PP-4). The SUERC in situ 14C extraction system was built in 2001 and is based on a combustion technique following the design of the extraction system at the University of Arizona. Our preliminary results suggest that the continuous running of the extraction system and the monitoring of gas collecting time and of the temperature of the cryogenic traps used in the gas cleaning steps are key to maintaining low and stable system blanks. Our latest average system blank is 2.02 ± 0.23 x 105 14C atoms. This is consistent with those recently published by the University of Arizona and ETH in situ ...
The identification of tephra within varved deposits of a former ice-dammed lake that 11 existed i... more The identification of tephra within varved deposits of a former ice-dammed lake that 11 existed in Scotland during the Younger Dryas provides an opportunity to calibrate 12 10 Be production rates using previously published 10 Be concentrations from the lake 13 shoreline and independently derived ages for the tephra's derived from the Greenland 14 Ice Core records. The best-estimate ages of the tephras yield indistinguishable 10 Be 15 production rate values for spallation with an average value of 4.26 ± 0.21 atoms g-1 a-1 16 using the 'Lm' scaling scheme. These values are in best agreement with the most 17 proximal reference 10 Be production rate from Norway.
The sustainable use of soils represents one of the key challenges that society faces. Glacial sed... more The sustainable use of soils represents one of the key challenges that society faces. Glacial sediments (tills and moraines) form the parent material of soils in many parts of the northern hemisphere but little is known about the histories of these soils. Several methods of estimating soil erosion exist but these have limitations, mainly in that they are unable to
We describe improvements to the in situ cosmogenic C-14 extraction system at SUERC made since 200... more We describe improvements to the in situ cosmogenic C-14 extraction system at SUERC made since 2004 and present new in situ cosmogenic C-14 and Be-10 data testing whether depth-profiles of these nuclides can be used to determine amounts and timing of erosion on a soil formed on a Younger Dryas moraine in Scotland. The SUERC in situ C-14 extraction system
Enlighten-Research publications by members of the University of Glasgow http://eprints.gla.ac.uk ... more Enlighten-Research publications by members of the University of Glasgow http://eprints.gla.ac.uk Lake Store Finnsjøen-a key for understanding Late-Glacial/early Holocene vegetation and ice sheet dynamics in the central Scandes Mountains
ABSTRACT The present study aims at testing the possibility of using the in-situ cosmogenic burial... more ABSTRACT The present study aims at testing the possibility of using the in-situ cosmogenic burial dating technique on deltaic deposits. The sequence analyzed is exposed along the Ligurian coast (north-west Italy) and is made of proximal marine and continental deposits previously considered Pliocene or Plio-Quaternary in age. In the study area two allostratigraphic units were recognized. The lower unit represents the evolution of a small coarse-grained delta developed in a fjord or embayment environment. The coarsening / shallowing upward trend observed within the sections, from bottom to top, suggests that the delta prograded rapidly in the landward portion of the canyon placed opposite to the paleo-river outlet. Within the deltaic sequence the transgressive and highstand system tracts were recognized. The unit 2 is composed by several alluvial fan systems deposited in small incised valleys developed within the previously, uplifted deltaic deposits and successively incised by a braided river system. In-situ produced cosmogenic nuclides were used in order to date the age of the deposition of the deltaic deposits. Results suggest that the studied deltaic sediments belonging to the unit 1 were deposited between 1,300,000 and 200,000 year ago thus during the Lower to Middle Pleistocene, whereas the unit 2 was deposited during the Middle Pleistocene as a consequence of a tectonically driven uplift phase. Furthermore samples collected within the prograding part of the delta show the higher denudation rates. The obtained results demonstrate that burial ages and related erosion rates inferred from cosmogenic nuclides concentrations can be considered as a very useful tool to reconstruct the sea level changes over the past 1 million year.
ABSTRACT The widely accepted concept that ice sheet erosion is both pervasive and highly signific... more ABSTRACT The widely accepted concept that ice sheet erosion is both pervasive and highly significant in landscape modification in glaciated areas has been tested in northern Sweden using field mapping and cosmogenic nuclide techniques. The following lines of evidence suggest that this concept does not apply to recent glaciations in this region: (i) relict portions of mountainous landscapes have been unmodified by glacial erosion for at least 845 kyr, despite multiple glaciations. We base this estimate on the contrast between in situ cosmogenic 10Be and 26Al concentrations from erratics on relict surfaces and glacially eroded bedrock adjacent to these surfaces (consistent last deglaciation exposure ages, ˜8--13 kyr), compared to exposure ages of 34 kyr to 61 kyr on bedrock surfaces in these same relict areas, demonstrating that these areas were preserved through multiple glacial cycles. (ii) relict lowland landscape elements, tors, have been essentially unmodified by glacial erosion for at least 605 kyr. We base this estimate on apparent 10Be and 26Al exposure ages of tor summit bedrock surfaces ranging between 79 and 37 ka, in an area deglaciated at 11 ka, suggesting that these relict landforms have survived glaciation with little or no erosion. (iii) areas of apparent significant glacial modification have undergone limited erosion during the last glacial cycle. Cosmogenic 10Be and 36Cl data from one glacial corridor and adjacent relict surfaces match temporal and spatial variations of glacial erosion that were suggested by geomorphological mapping. However, glacial erosion estimates in what appear to be heavily scoured areas indicate erosion of only ˜2 ± 0.4 m of bedrock during the last glaciation, based on cosmogenic nuclide inheritance. Although surprisingly low, this rock loss depth does yield an erosion rate for the glacial corridor that is at least an order of magnitude higher than maximum erosion rates over relict surfaces, which typically are 1--2 m/Ma. These results indicate that the overall modification produced by ice sheets along glacial corridors may either be more restricted than previously thought, or occurred preferentially during earlier Quaternary glacial periods. Erosion over relict surfaces, which comprises about 20% of the area in the northern Swedish mountains and most of the eastern mountain foreland, has been negligible, and these relict areas need to be accounted for as frozen bed patches in basal boundary conditions for ice sheet and landscape development models.
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Papers by Derek Fabel