Drift-filled hollows in Battersea: investigation of the structure and geology along the route of the Northern Line Extension, London
File(s)
Accepted version
Author(s)
Toms, E
Mason, PJ
Ghail, RC
Type
Journal Article
Abstract
Drift filled hollows (DFHs) are a major subsurface hazard for engineering in London. They are characterised by a steeply inclined cone-shaped hollow into (sometimes through) the London Clay Formation, filled with unconsolidated fine to coarse-grained drift and often covered by terrace gravels, making them difficult to identify at the surface. Their origin remains uncertain but most likely formed towards the end of glacial epochs by meltwater scouring, perhaps of collapsed pingos. Usually associated with tributaries to the Thames, DFHs are particularly prevalent in the Battersea area, through which the Northern Line Extension (NLE) is to be built. This study uses 283 public borehole records and site reports to build a 3D geological ground model of two known DFHs in the Battersea area to develop a more complete understanding of their origin. We show that DFHs are likely older than previously assumed, dating from the end Anglian [MIS 12], ~300 ka ago, before the deposition of the River Terrace Deposits. The two DFHs modelled fall into distinct types: a small shallow DFH that is probably a purely scour feature in origin, and a larger, deeper DFH which probably formed by the scouring of a perhaps fault controlled pingo. It is unclear whether the faults controlled pingo formation passively by acting as a conduit for water, or in a more active sense by driving ground movements. Both DFHs represent a significant hazard for the NLE and require more detailed investigations to properly constrain their extent.
Date Issued
2016-05-17
Date Acceptance
2016-04-14
Citation
Quarterly Journal of Engineering Geology and Hydrogeology, 2016, 49 (2), pp.147-153
ISSN
1470-9236
Publisher
Geological Society
Start Page
147
End Page
153
Journal / Book Title
Quarterly Journal of Engineering Geology and Hydrogeology
Volume
49
Issue
2
Copyright Statement
© 2016 The Author(s)
Subjects
Science & Technology
Technology
Physical Sciences
Engineering, Geological
Geosciences, Multidisciplinary
Engineering
Geology
SOUTHERN BRITAIN
UK
Geological & Geomatics Engineering
0406 Physical Geography And Environmental Geoscience
0905 Civil Engineering
Publication Status
Published