Engineering geology of British rocks and soils : Gault Clay

Abstract

The Gault is a sequence of clays, mudstones and thin siltstones
\nwith bands of phosphatic nodules of Middle and
\nUpper Albian age. Its outcrop stretches south-westward
\nfron1 East Anglia through Wessex to west Dorset and surrounds
\nthe Weald in an arc from North East Kent westwards
\nthrough Surrey to Hampshire where it turns south
\nand returns· eastward through west and east Sussex. The
\nGault clay thickens to the south and reaches its maximum
\ndeveloplnent of over 100 m in the Weald and thins to the
\nwest as it passes into Hampshire and Dorset.
\nThe Gault clay contains both clay and non-clay mineralso
\nThe major non-clay minerals are quartz and calcite.
\nQuartz usually makes up about 20% or more of the Gault
\nand its distribution is fairly uniform. Calcite is present as
\nfossil debris and as a cementing agent. The Gault is more
\ncalcareous in the north east than the south and west.