Recent advances in the understanding of Quaternary periglacial features of the English Channel coastlands

Murton, Julian B.; Lautridou, Jean‐Pierre

doi:10.1002/jqs.748

Cited by 34 publications

(19 citation statements)

References 38 publications

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“…The permafrost cap might reduce aquifer recharge and there is evidence for increased runoff in the region during cold stages (Cheetham 1980;Collins et al 1996). The depth of permafrost within the London Basin during the Quaternary is not well defined (Hutchinson & Thomas-Betts 1990;Murton & Lautridou 2003), but a depth of permafrost of about 105 m is implicit in the study by Hutchinson (1991). Within the central parts of the London Basin, the Chalk is largely confined by a thickness of Palaeocene Sands, the Lambeth Group and the London Clay Formation.…”

Section: Ground Ice Relictsmentioning

confidence: 99%

Anomalous buried hollows in London: development of a hazard susceptibility map

Banks

Bricker

Royse

et al. 2015

QJEGH

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Engineering works carried out in central London over many decades have revealed a number of buried hollows that exhibit curious characteristics. Some extend deep into the bedrock geology and are in-filled with disturbed superficial deposits and reworked bedrock. Others are contained within the superficial deposits. They can be up to 500 m wide and more than 60 m in depth. As the infill material often has different behavioural characteristics from the surrounding deposits failure to identify them during an initial site investigation can prove costly. This paper considers their common characteristics and describes the method used to develop a buried hollow hazard susceptibility map. This map provides planners with a broader awareness of the potential location of difficult ground conditions associated with them, thereby reducing the potential for unforeseen ground conditions through effective site investigation design. The paper continues with a discussion of some of the likely processes associated with their formation, which are attributed to cryogenic processes, and concludes with potential future research directions.

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Section: Ground Ice Relictsmentioning

confidence: 99%

Anomalous buried hollows in London: development of a hazard susceptibility map

Banks

Bricker

Royse

et al. 2015

QJEGH

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“…Alternatively, a completely different pattern, involving two lines of re-colonization, is possible. In addition to the one from the East, a second front reached Central and Northern Europe from either Iberia ("brown bear paradigm"; Hewitt, 1999) or refugia on the British Isles (there is growing evidence of unglaciated areas on the British Isles during the last ice age: e.g., Sinclair et al, 1998;Stewart & Lister, 2001;Hän-fling et al, 2002;Murton & Lautridou, 2003;Hoarau et al, 2007;Remerie et al, 2009). The location of the contact zone is similar to that hypothesized for the butterfly Maniola jurtina , which, however, expanded only from southern refugia (not from the British Isles).…”

Section: Postglacial Re-colonizationmentioning

confidence: 99%

The aquatic leaf beetle Macroplea mutica (Coleoptera: Chrysomelidae) in Europe: Population structure, postglacial colonization and the signature of passive dispersal

Mende¹,

Biström²,

Meichssner³

et al. 2010

Eur. J. Entomol.

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Abstract. The pattern of postglacial re-colonization of Europe and the present population structure are known for various plant and animal species. The reed beetle Macroplea mutica (Fabricius, 1792) has characteristics that should influence both aspects in a peculiar way and therefore complement the currently known scenarios: It is fully aquatic but cannot swim or fly. Samples from 25 European populations of M. mutica and five specimens from China were investigated using amplified fragment length polymorphism (AFLP, 251 loci). Assessment of error rates associated with this method showed that the data set contains a strong population genetic signal. As hypothesized pronounced population differentiation and signs of inbreeding were found. Italian populations are clearly differentiated from northern populations (and from each other), which underlines the role of the Alps as a major barrier. Specimens from Lake Balaton (Hungary) show some affiliation with the populations in the Baltic Sea, which are all relatively similar. Populations from the eastern part of Northern Germany are similar to the Baltic populations, while those from the western part are allied to the British populations. The hypothesis is that the recolonization of Europe was from both the Southeast and a western refugium in the area of present-day southern England or Ireland, which resulted in a suture zone in Northern Germany. The effect of passive dispersal by drift attached to host plant material (especially in the Baltic Sea) and by zoochory (migrating waterfowl) is discussed.

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“…The presence of periglacial features such as pingos on Dartmoor (Ballantyne & Harris, 1993) suggests a mean annual temperature of -3 to -1°C (Mackay 1988) within 20-30 km of the cave for at least some of the Devensian glacial period, but this evidence is not strong enough to allow a confident estimate of glacial mean annual temperatures for Kents Cavern itself. Various references (see review in Murton & Lautridou, 2003) suggest a mean annual temperature below zero in this part of Britain for much of isotope stage 2. Conservatively, if we assume that the mean annual temperature was only about half the modern value, i.e.…”

Section: Heat Flow Estimatementioning

confidence: 95%

Cryogenic fracturing of calcite flowstone in caves: theoretical considerations and field observations in Kents Cavern, Devon, UK

Lundberg

McFarlane

2012

IJS

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Several caves in Devon, England, have been noted for extensive cracking of substantial flowstone floors. Conjectural explanations have included earthquake damage, local shock damage from collapsing cave passages, hydraulic pressure, and cryogenic processes. Here we present a theoretical model to demonstrate that frost-heaving and fracture of flowstone floors that overlie wet sediments is both a feasible and likely consequence of unidirectional air flow or cold-air ponding in caves, and argue that this is the most likely mechanism for flowstone cracking in caves located in Pleistocene periglacial environments outside of tectonically active regions. Modeled parameters for a main passage in Kents Cavern, Devon, demonstrate that 1 to 6 months of -10 to -15° C air flow at very modest velocities will result in freezing of 1 to 3 m of saturated sediment fill. The resultant frost heave increases with passage width and depth of frozen sediments. In the most conservative estimate, freezing over one winter season of 2 m of sediment in a 6-m wide passage could fracture flowstone floors up to ~13 cm thick, rising to ~23 cm in a 12-m wide passage. Natural flaws in the flowstone increase the thickness that could be shattered. These numbers are quite consistent with the field evidence.

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Recent advances in the understanding of Quaternary periglacial features of the English Channel coastlands

Cited by 34 publications

References 38 publications

Anomalous buried hollows in London: development of a hazard susceptibility map

Anomalous buried hollows in London: development of a hazard susceptibility map

The aquatic leaf beetle Macroplea mutica (Coleoptera: Chrysomelidae) in Europe: Population structure, postglacial colonization and the signature of passive dispersal

Cryogenic fracturing of calcite flowstone in caves: theoretical considerations and field observations in Kents Cavern, Devon, UK

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