Malton, United Kingdom
Malton, United Kingdom

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Lundberg J.,Carleton University | Lord T.C.,Lower Winskill | Lord T.C.,Lancaster University | Murphy P.J.,University of Leeds
Geosphere | Year: 2010

We present 23 new thermal ionization mass spectrometric U-Th dates for Victoria Cave, North Yorkshire, UK. Victoria Cave underwent repeated glaciation during the late Pleistocene and contains one of the longest Quaternary cave sequences in Britain. The dates reveal that speleothem formation began beyond the range of the dating technique (before 600 ka). Finite reproducible dates of 490-9/+10 ka confi rm speleothem deposition during marine isotope stage (MIS) 13, the oldest date we know of for this part of Britain. Further speleothem formation was dated to MIS 11, MIS 9, MIS 7, and MIS 5. The results are the basis for a new chronology of Quaternary events for the cave and greatly enhance our understanding of the factors affecting the formation of the sedimentary sequence. Cyclical climatic and environmental change throughout the late Pleistocene triggered cyclical sedimentation events in the cave. All the interglacial periods show calcite deposition but with growth phases postdating the warmest events of MIS 11 and MIS 5e. The position of the cave halfway up the side of a glacial trough resulted in very distinctive sediment during the more extreme glacial maxima: ice-dammed lakes formed inside the cave and deposited varvelike clay rhythmites. The dates inferred for these deposits suggest that this locality underwent signifi cant glaciation during MIS 12, MIS 10, MIS 6, and MIS 2, and that the ice was warm based. The absence of rhythmites during MIS 8 suggests minimal ice cover at that time. This is the most complete record for glacial events in the region; it is the only site where successive glacial maxima can be identifi ed and dated. The record of large faunal remains indicates that the cave was open to the surface, only for relatively short times, during MIS 13, MIS 12, MIS 5e, the Late Glacial Interstadial, and parts of the Holocene. It is inferred that at other times the cave was closed because scree formation blocked the entrance. The record of vertebrate remains is therefore controlled by geomorphological processes. The deteriorating state of this unprotected site remains a cause for concern. © 2010 Geological Society of America.


Murphy P.J.,University of Leeds | Faulkner T.L.,University of Birmingham | Lord T.C.,Lower Winskill | Thorp J.A.,5 Holme Park
Cave and Karst Science | Year: 2015

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 ice-dammed 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 jokulhlaup 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. © British Cave Research Association 2015.


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. © 2015, The Author(s) 2015.


Edwards C.J.,University of Oxford | Edwards C.J.,Trinity College Dublin | Ho S.Y.W.,University of Sydney | Barnett R.,University of Oxford | And 5 more authors.
Quaternary Science Reviews | Year: 2014

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 etal., 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. © 2013 Elsevier Ltd.


Wilson P.,University of Ulster | Lord T.,Lower Winskill | Schnabel C.,Scottish Enterprise | Vincent P.J.,Lancaster University
Proceedings of the Yorkshire Geological Society | Year: 2013

Four gritstone outcrops around the summit rim of Ingleborough in the Yorkshire Dales, northern England, have yielded early to mid-Holocene cosmogenic 10Be 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. © The Geological Society of London 2014.


Wilson P.,University of Ulster | Lord T.,Lower Winskill | Rodes A.,Scottish Universities Environmental Research Center
Cave and Karst Science | Year: 2013

Four erratic boulders of Shap granite on the limestone terrain of eastern Cumbria have yielded cosmogenic nuclide (10Be) surface exposure ages that indicate the area was deglaciated c.17 ka ago. This timing is in accord with other ages pertaining to the loss of glacial ice cover in the Yorkshire Dales and north Lancashire, to the south, and the Lake District, to the west, and constrains the resumption of landscape (re)colonization and surface and sub-surface karstic processes. Marked shifts in climate are known to have occurred since deglaciation and combined with human impacts on the landscape the glaciokarst has experienced a complex pattern of environmental changes. Understanding these changes and their effects is crucial if the 'post-glacial' evolution of the glaciokarst is to be deciphered. © British Cave Research Association 2013.


Wilson P.,University of Ulster | Lord T.C.,Lower Winskill
Cave and Karst Science | Year: 2012

Contrasting rates of limestone dissolution to account for the development of limestone pedestals beneath erratic boulders at Norber, North Yorkshire, have been proposed. Most of these estimates were made prior to reliable dates being available for erratic emplacement and prior to detailed knowledge of the pattern of regional 'post-glacial' climate change. The erratics were deposited c. 18 ka BP, and for a substantial part of the ensuing c. 4 ka a climate of Arctic severity prevailed until the abrupt warming at 14.7 ka BP, marking the onset of the Lateglacial Interstadial. We propose that nivation (snowrelated) processes operated for much ofthat time, and again during the Younger Dryas Stadial (12.9 - 11.7 ka BP), and made a contribution to the lowering of the limestone surface by both mechanical and chemical action. Similar processes are likely to have operated for short periods on several occasions during the Holocene when, according to proxy records, climate deteriorated. We question previous views that dissolution occurred in an entirely temperate sub-regolith environment and/or was achieved solely by rainfall. © British Cave Research Association 2012.


Wilson P.,University of Ulster | Lord T.C.,Lower Winskill | Telfer M.W.,University of Plymouth | Barrows T.T.,University of Exeter | Vincent P.J.,Lancaster University
Geology Today | Year: 2013

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. © 2013 Blackwell Publishing Ltd, The Geologists' Association & The Geological Society of London.


Wilson P.,University of Ulster | Barrows T.T.,University of Exeter | Lord T.C.,Lower Winskill | Vincent P.J.,Lancaster University
Earth Surface Processes and Landforms | Year: 2012

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 17.9ka the limestone pavement has been lowered by 22-45cm (average: 33±10cm), 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. © 2012 John Wiley & Sons, Ltd.


Vincent P.J.,Lancaster University | Wilson P.,University of Ulster | Lord T.C.,Lower Winskill | Lord T.C.,Lancaster University | And 2 more authors.
Proceedings of the Geologists' Association | Year: 2010

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. © 2010 The Geologists' Association.

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