Tom Lord - Academia.edu (original) (raw)
Papers by Tom Lord
Briefing. The Magazine of the Yorkshire Archaeological and Historical Society, 2019
AMS radio-carbon dated Early and Middle Neolithic funerary activity in limestone caves in the Yor... more AMS radio-carbon dated Early and Middle Neolithic funerary activity in limestone caves in the Yorkshire Dales National Park
Proceedings Cumberland Geological Society, 2018
Cave and Karst Science, Vol. 44, No. 2, pp. 76-81. Transactions of the British Cave Research Asso... more Cave and Karst Science, Vol. 44, No. 2, pp. 76-81. Transactions of the British Cave Research Association.
Terrestrial cosmogenic nuclide (10 Be) surface-exposure ages are reported for three glacially-transported gritstone boulders and one glacially-scoured exposure of gritstone bedrock in the vicinity of Stump Cross Caverns, North Yorkshire. Although the ages do not form a statistically consistent cluster, three of them nevertheless indicate that the transport and deposition of boulders was by ice of the last (Late Devensian) glaciation. The ages provide evidence for glacier ice at the Wharfe–Nidd interfluve, in contrast to previously held views that these uplands had remained above the level of the last ice sheet. The youngest of the three ages on boulders (~18.5 ka) is taken as the best estimate for deglaciation of the area. This is consistent both with surface-exposure ages from sites elsewhere around the southern margin of the Yorkshire Dales and with uranium-series dated speleothems in Stump Cross Caverns. Together these results reveal that deglaciation of the Dales was most likely well advanced by ~18–16 ka, facilitating the rejuvenation of surface and subsurface karstic processes.
A highly unusual pit fall ungulate assemblage dominated by wild boar (Sus scrofa) was recovered d... more A highly unusual pit fall ungulate assemblage dominated by wild boar (Sus scrofa) was recovered during the recent exploration of a cave shaft in the upland
karstic landscape of northwest England. Both the opening of the cave shaft to the surface and its infilling by clastic sediments are attributable to accelerated
landscape erosion associated with the 9.3 ka BP climatic deterioration. Evidence that wild boar had died in winter or spring suggests that their deaths
relate to the prolonged periods of annual snow cover experienced by the uplands of northwest England during the 9.3 ka BP event. The dominance of
wild boar in the pit fall assemblage is explained by the snow pack concealing the open shaft and turning it into a baited trap for wild boar whenever it
contained carrion. Wild boar bones splintered and chewed by wild boar demonstrate carrion cannibalism. Human presence is attested by slight butchery
to an aurochs (Bos primigenius). How Mesolithic people adapted to climate change associated with the 9.3 ka BP event is a subject well worth pursuing.
Abstract: The prominent Giggleswick Scar at the South Craven Fault extremity of the Carboniferous... more Abstract: The prominent Giggleswick Scar at the South Craven Fault extremity of the Carboniferous
limestone of the Askrigg Block in North Yorkshire, UK, contains relict phreatic caves whose
speleogenesis is enigmatic. This paper examines the local geomorphological evidence and proposes
that some, but not necessarily all, karst features along and above the Scar formed after the Last Glacial
Maximum. Building on a previous deglacial model for the Yorkshire Dales, it is hypothesized that
inception fractures and bedding plane partings were created during isostatic uplift. These were then
likely enlarged by dissolution in cold unsaturated meltwater beneath a local flowing deglacial icedammed
lake that formed initially at an altitude of c.300m, with a catchment area of c. 2km2 . Rising
cupolas outside Gully Cave were probably formed at c. 18ka BP by meltwater flowing up into a moulin
within the ice, which continued to be cold-based farther south. As the ice-sheet slowly downwasted, the
surface of the lake would have widened and lowered past the newly-formed cave entrances. Some of
these were probably enlarged by freeze-thaw and lake-ice push and pull processes. Indeed, the heights
of some enlarged entrances correspond to proposed stabilizing lake overflow levels. It is also assumed
that the local ice-dammed lake coalesced with the main Settle glacial lake, until a jökulhlaup created a
ravine above pre-existing glacial scoops in the limestone cliff. Thereafter, the lake split into two parts
on each side of Buckhaw Brow, whilst still inundating the lower caves. If this hypothesis applies, it has
wider implications for cave speleogenesis and sedimentation in the Yorkshire Dales.
Brown bears recolonised Europe rapidly after the Last Glacial Maximum (LGM), but there has been d... more Brown bears recolonised Europe rapidly after the Last Glacial Maximum (LGM), but there has been debate about whether bear populations were confined to separate glacial refugia in southern Europe, or if there was continuous gene flow among groups. To look in more detail at recolonisation routes into the British Isles after the LGM, 16 brown bear (Ursus arctos) samples from Lateglacial Yorkshire were analysed for mitochondrial DNA survival. The resulting data were compared with earlier work on Late Pleistocene and Holocene bears from Ireland (Edwards et al., 2011), as well as with both modern and ancient bears from across continental Europe. The results highlight the temporal and spatial continuity of brown bear maternal lineages through the Lateglacial period in northern England. While this region was not a refugial area in the LGM for the Irish Clade 2 brown bears, our data suggest that populations of brown bear in England did act as refugial sources for the later colonisation of Ireland, by Clade 1-i bears, during the Holocene. Our results contribute to a wider understanding of the phylogenetic relationships of brown bears through the Late Quaternary, and lend a valuable perspective on bear migration into peripheral Europe.
Four gritstone outcrops around the summit rim of Ingleborough in the Yorkshire Dales, northern En... more Four gritstone outcrops around the summit rim of Ingleborough in the Yorkshire Dales, northern England, have yielded early to mid-Holocene cosmogenic
10 Be surface exposure ages, ranging from 10.61 ± 0.53 ka to 6.84 ± 0.35 ka. Taken at face value, the ages indicate that the outcrops became exposed to cosmic radiation at different times and consequently were not necessarily exposed
as a result of the same single process at each site. Erosion of overlying gritstone debris during periods of climatic deterioration, during construction of a stone rampart, and during rock-slope failure may have all contributed to the exposure ages of these surfaces. Some of the ages may be compound in that a component of their isotope signal was acquired prior to the complete removal of the former debris
cover. Although interpretation of the data set involves some speculation, the ages and topographic context of the samples indicate that the processes and timing of mountain top erosion may vary at small spatial scales.
Geology Today. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2451.2013.00859.x/pdf
"The Craven Dales of North Yorkshire contain some of the finest examples of limestone geology an... more "The Craven Dales of North Yorkshire contain some of the finest examples of limestone geology and landscape in the UK. The extensive limestone pavements with their clints, grikes and other water-worn features, are a key attraction for both scientists and recreational visitors. Likewise the cave systems attract attention with their remarkable sediment accumulations, some of which are in excess of 500 000 years old and others contain the
bones of mammals that are either extinct or no longer present in the British Isles. The glacial erratic boulders at Norber and the loessic sediments that, in places, mask the limestone have also provided stimulus for investigation. Summarized below are the findings of several recent studies that focussed on establishing the age of various features. Whilst the reports answer some
long-standing questions, they also demonstrate that there is still much that can be learned about this seemingly familiar territory."
Caves and Karst of the Yorkshire Dales. , 2013
Prehistoric Yorkshire, 2013
Cave and Karst Science, 2012
Earth Surface Processes and Landforms, 2012
Determination of the rate and total amount of limestone pavement surface lowering is a critical i... more Determination of the rate and total amount of limestone pavement surface lowering is a critical issue in developing models of regional landscape change in limestone terrain. Erratic-capped pedestals have frequently been used for this purpose but problems concerning definition and measurement of pedestal height, and the absence of a secure timeframe for erratic emplacement, have resulted in conflicting interpretations. We have used cosmogenic (36Cl) to establish the emplacement age of erratic boulders and the total amount of pavement surface lowering at sites in northwest England. Since erratic emplacement at 17.9 ka the limestone pavement has been lowered by 22–45 cm (average: 33 ± 10 cm), assuming lowering was continuous. Although indicating some spatial heterogeneity, the results contrast with earlier reported values based on the measurement of pedestal heights and inferred age for deglaciation. We consider that changes in climate and the character and duration of regolith covers to have been important influences in promoting surface lowering. It is argued that nivation (chemical and mechanical snow-related processes) associated with several cool/cold periods is likely to have played an important role in surface lowering. Complicating factors associated with surface lowering (thickness and longevity of snow and regolith covers) are identified but as yet cannot be quantified.
Earth Surface Processes and Landforms, 2012
Proceedings of The Geologists Association, 2010
Cosmogenic isotope (36Cl) surface exposure dating of four of the erratic boulders at Norber in th... more Cosmogenic isotope (36Cl) surface exposure dating of four of the erratic boulders at Norber in the Yorkshire Dales National Park, northwest England, yielded mean ages of ∼22.2±2.0ka BP and ∼18.0±1.6ka BP for their emplacement. These two mean values derive from different 36Cl production rates used for exposure age calculation. The ages are uncorrected for temporal variations in production rates and may underestimate the true ages by 5-7%. The former age, although implying early deglaciation for this area of the British ice sheet, is not incompatible with minimum deglaciation ages from other contexts and locations in northwest England. However, the latter age is more consistent with the same minimum deglaciation ages and geochronological evidence for ice-free conditions in parts of the northern sector of the Irish Sea. Within uncertainties, the younger of the mean ages from Norber may indicate that boulder emplacement was associated with North Atlantic Heinrich event 1. The limited spatial (downvalley) extent of the Norber boulders implies that at the time of their deposition the ice margin was coincident with the distal margin of the erratic train. Loss of ice cover at Norber was followed by persistent stadial conditions until the abrupt opening of the Lateglacial Interstadial when large carnivorous mammals colonised the area. The 36Cl ages are between ∼3.0ka and ∼13.0ka older than previous estimates based on rates of limestone dissolution derived from the heights of pedestals beneath the erratics
Briefing. The Magazine of the Yorkshire Archaeological and Historical Society, 2019
AMS radio-carbon dated Early and Middle Neolithic funerary activity in limestone caves in the Yor... more AMS radio-carbon dated Early and Middle Neolithic funerary activity in limestone caves in the Yorkshire Dales National Park
Proceedings Cumberland Geological Society, 2018
Cave and Karst Science, Vol. 44, No. 2, pp. 76-81. Transactions of the British Cave Research Asso... more Cave and Karst Science, Vol. 44, No. 2, pp. 76-81. Transactions of the British Cave Research Association.
Terrestrial cosmogenic nuclide (10 Be) surface-exposure ages are reported for three glacially-transported gritstone boulders and one glacially-scoured exposure of gritstone bedrock in the vicinity of Stump Cross Caverns, North Yorkshire. Although the ages do not form a statistically consistent cluster, three of them nevertheless indicate that the transport and deposition of boulders was by ice of the last (Late Devensian) glaciation. The ages provide evidence for glacier ice at the Wharfe–Nidd interfluve, in contrast to previously held views that these uplands had remained above the level of the last ice sheet. The youngest of the three ages on boulders (~18.5 ka) is taken as the best estimate for deglaciation of the area. This is consistent both with surface-exposure ages from sites elsewhere around the southern margin of the Yorkshire Dales and with uranium-series dated speleothems in Stump Cross Caverns. Together these results reveal that deglaciation of the Dales was most likely well advanced by ~18–16 ka, facilitating the rejuvenation of surface and subsurface karstic processes.
A highly unusual pit fall ungulate assemblage dominated by wild boar (Sus scrofa) was recovered d... more A highly unusual pit fall ungulate assemblage dominated by wild boar (Sus scrofa) was recovered during the recent exploration of a cave shaft in the upland
karstic landscape of northwest England. Both the opening of the cave shaft to the surface and its infilling by clastic sediments are attributable to accelerated
landscape erosion associated with the 9.3 ka BP climatic deterioration. Evidence that wild boar had died in winter or spring suggests that their deaths
relate to the prolonged periods of annual snow cover experienced by the uplands of northwest England during the 9.3 ka BP event. The dominance of
wild boar in the pit fall assemblage is explained by the snow pack concealing the open shaft and turning it into a baited trap for wild boar whenever it
contained carrion. Wild boar bones splintered and chewed by wild boar demonstrate carrion cannibalism. Human presence is attested by slight butchery
to an aurochs (Bos primigenius). How Mesolithic people adapted to climate change associated with the 9.3 ka BP event is a subject well worth pursuing.
Abstract: The prominent Giggleswick Scar at the South Craven Fault extremity of the Carboniferous... more Abstract: The prominent Giggleswick Scar at the South Craven Fault extremity of the Carboniferous
limestone of the Askrigg Block in North Yorkshire, UK, contains relict phreatic caves whose
speleogenesis is enigmatic. This paper examines the local geomorphological evidence and proposes
that some, but not necessarily all, karst features along and above the Scar formed after the Last Glacial
Maximum. Building on a previous deglacial model for the Yorkshire Dales, it is hypothesized that
inception fractures and bedding plane partings were created during isostatic uplift. These were then
likely enlarged by dissolution in cold unsaturated meltwater beneath a local flowing deglacial icedammed
lake that formed initially at an altitude of c.300m, with a catchment area of c. 2km2 . Rising
cupolas outside Gully Cave were probably formed at c. 18ka BP by meltwater flowing up into a moulin
within the ice, which continued to be cold-based farther south. As the ice-sheet slowly downwasted, the
surface of the lake would have widened and lowered past the newly-formed cave entrances. Some of
these were probably enlarged by freeze-thaw and lake-ice push and pull processes. Indeed, the heights
of some enlarged entrances correspond to proposed stabilizing lake overflow levels. It is also assumed
that the local ice-dammed lake coalesced with the main Settle glacial lake, until a jökulhlaup created a
ravine above pre-existing glacial scoops in the limestone cliff. Thereafter, the lake split into two parts
on each side of Buckhaw Brow, whilst still inundating the lower caves. If this hypothesis applies, it has
wider implications for cave speleogenesis and sedimentation in the Yorkshire Dales.
Brown bears recolonised Europe rapidly after the Last Glacial Maximum (LGM), but there has been d... more Brown bears recolonised Europe rapidly after the Last Glacial Maximum (LGM), but there has been debate about whether bear populations were confined to separate glacial refugia in southern Europe, or if there was continuous gene flow among groups. To look in more detail at recolonisation routes into the British Isles after the LGM, 16 brown bear (Ursus arctos) samples from Lateglacial Yorkshire were analysed for mitochondrial DNA survival. The resulting data were compared with earlier work on Late Pleistocene and Holocene bears from Ireland (Edwards et al., 2011), as well as with both modern and ancient bears from across continental Europe. The results highlight the temporal and spatial continuity of brown bear maternal lineages through the Lateglacial period in northern England. While this region was not a refugial area in the LGM for the Irish Clade 2 brown bears, our data suggest that populations of brown bear in England did act as refugial sources for the later colonisation of Ireland, by Clade 1-i bears, during the Holocene. Our results contribute to a wider understanding of the phylogenetic relationships of brown bears through the Late Quaternary, and lend a valuable perspective on bear migration into peripheral Europe.
Four gritstone outcrops around the summit rim of Ingleborough in the Yorkshire Dales, northern En... more Four gritstone outcrops around the summit rim of Ingleborough in the Yorkshire Dales, northern England, have yielded early to mid-Holocene cosmogenic
10 Be surface exposure ages, ranging from 10.61 ± 0.53 ka to 6.84 ± 0.35 ka. Taken at face value, the ages indicate that the outcrops became exposed to cosmic radiation at different times and consequently were not necessarily exposed
as a result of the same single process at each site. Erosion of overlying gritstone debris during periods of climatic deterioration, during construction of a stone rampart, and during rock-slope failure may have all contributed to the exposure ages of these surfaces. Some of the ages may be compound in that a component of their isotope signal was acquired prior to the complete removal of the former debris
cover. Although interpretation of the data set involves some speculation, the ages and topographic context of the samples indicate that the processes and timing of mountain top erosion may vary at small spatial scales.
Geology Today. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2451.2013.00859.x/pdf
"The Craven Dales of North Yorkshire contain some of the finest examples of limestone geology an... more "The Craven Dales of North Yorkshire contain some of the finest examples of limestone geology and landscape in the UK. The extensive limestone pavements with their clints, grikes and other water-worn features, are a key attraction for both scientists and recreational visitors. Likewise the cave systems attract attention with their remarkable sediment accumulations, some of which are in excess of 500 000 years old and others contain the
bones of mammals that are either extinct or no longer present in the British Isles. The glacial erratic boulders at Norber and the loessic sediments that, in places, mask the limestone have also provided stimulus for investigation. Summarized below are the findings of several recent studies that focussed on establishing the age of various features. Whilst the reports answer some
long-standing questions, they also demonstrate that there is still much that can be learned about this seemingly familiar territory."
Caves and Karst of the Yorkshire Dales. , 2013
Prehistoric Yorkshire, 2013
Cave and Karst Science, 2012
Earth Surface Processes and Landforms, 2012
Determination of the rate and total amount of limestone pavement surface lowering is a critical i... more Determination of the rate and total amount of limestone pavement surface lowering is a critical issue in developing models of regional landscape change in limestone terrain. Erratic-capped pedestals have frequently been used for this purpose but problems concerning definition and measurement of pedestal height, and the absence of a secure timeframe for erratic emplacement, have resulted in conflicting interpretations. We have used cosmogenic (36Cl) to establish the emplacement age of erratic boulders and the total amount of pavement surface lowering at sites in northwest England. Since erratic emplacement at 17.9 ka the limestone pavement has been lowered by 22–45 cm (average: 33 ± 10 cm), assuming lowering was continuous. Although indicating some spatial heterogeneity, the results contrast with earlier reported values based on the measurement of pedestal heights and inferred age for deglaciation. We consider that changes in climate and the character and duration of regolith covers to have been important influences in promoting surface lowering. It is argued that nivation (chemical and mechanical snow-related processes) associated with several cool/cold periods is likely to have played an important role in surface lowering. Complicating factors associated with surface lowering (thickness and longevity of snow and regolith covers) are identified but as yet cannot be quantified.
Earth Surface Processes and Landforms, 2012
Proceedings of The Geologists Association, 2010
Cosmogenic isotope (36Cl) surface exposure dating of four of the erratic boulders at Norber in th... more Cosmogenic isotope (36Cl) surface exposure dating of four of the erratic boulders at Norber in the Yorkshire Dales National Park, northwest England, yielded mean ages of ∼22.2±2.0ka BP and ∼18.0±1.6ka BP for their emplacement. These two mean values derive from different 36Cl production rates used for exposure age calculation. The ages are uncorrected for temporal variations in production rates and may underestimate the true ages by 5-7%. The former age, although implying early deglaciation for this area of the British ice sheet, is not incompatible with minimum deglaciation ages from other contexts and locations in northwest England. However, the latter age is more consistent with the same minimum deglaciation ages and geochronological evidence for ice-free conditions in parts of the northern sector of the Irish Sea. Within uncertainties, the younger of the mean ages from Norber may indicate that boulder emplacement was associated with North Atlantic Heinrich event 1. The limited spatial (downvalley) extent of the Norber boulders implies that at the time of their deposition the ice margin was coincident with the distal margin of the erratic train. Loss of ice cover at Norber was followed by persistent stadial conditions until the abrupt opening of the Lateglacial Interstadial when large carnivorous mammals colonised the area. The 36Cl ages are between ∼3.0ka and ∼13.0ka older than previous estimates based on rates of limestone dissolution derived from the heights of pedestals beneath the erratics
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"Ancient Walls" In Yorkshire, farmer Tom Lord tells presenter Peter France why he believes some ... more "Ancient Walls"
In Yorkshire, farmer Tom Lord tells presenter Peter France why he believes some of his own walls may be 800 years old and were built to deter wolves.
BCRA Cave Science Conference 2017 Abstracts
First Notice of Haggs Brow Cave excavations, Lower Winskill, Settle, North Yorkshire.