Geo-engineering properties and processes of the Lias Group

The Lias Group encompasses some of the most important geological formations in Britain. They have been involved in major engineering projects, industrial exploitation, and pioneering scientific research over the last two centuries.
The Lias Group consists mainly of clays, mudstones and limestones of latest Triassic and Early Jurassic age, deposited between 180 and 205 million years ago. The outcrop of the Lias extends in a continuous band from the coast of Dorset to Yorkshire, with outlying areas in Somerset and South Wales. Significant outcrops are found in the high sea-cliffs on the coasts of Dorset, South Wales, and Yorkshire.

Typical exposure of Lias Group mudrocks on the Dorset coast.
Typical exposure of Lias Group mudrocks on the Dorset coast.
As part of the Geo-engineering properties and processes of UK Rocks and Soils Project, an in-depth study of the Lias Group has used data held in the National Geotechnical Properties Database. The geological, lithological, geotechnical, and mineralogical features of the major formations within the Lias Group have been described in detail, including the processes and effects of weathering.

The main study areas across the Lias Group outcrop in England and Wales.
The main study areas across the Lias Group outcrop in England and Wales.

Hazards within the Lias Group

This study has shown that the Lias Group is prone to a number of geological hazards:

  • landslide
  • swell/shrink
  • radon
  • sulphate attack.

One of the main conclusions is that weathering has a strong influence on the engineering behaviour of this group.

For further information contact:enquiries@bgs.ac.uk