Chalk Group - Chalk Landscapes of England

Chalk Landscapes of England

The Chalk outcrops across large parts of southern and eastern England and forms a significant number of the major physiographical features. Whilst it has been postulated that a chalk cover was laid down across just about all of England and Wales during Cretaceous times, subsequent uplift and erosion has resulted in it remaining only southeast of a line drawn roughly between The Wash and Lyme Bay in Dorset and eastwards from the scarps of the Lincolnshire and Yorkshire Wolds. Gentle folding of the Mesozoic rocks of this region during the Alpine Orogeny has produced the London Basin and the Weald-Artois Anticline, the Hampshire Basin and the less gentle Purbeck-Wight monocline.

The broadly western margin of the Chalk outcrop is marked, from northeast to southwest, to south by the Chalk downlands of the Yorkshire Wolds, the Lincolnshire Wolds, a subdued feature through western Norfolk, including Breckland, the Chiltern Hills, the Berkshire Downs, Marlborough Downs and the western margins of Salisbury Plain and Cranborne Chase and the North and South Dorset Downs. In parts of the Thames Basin and eastern East Anglia the Chalk is concealed by later deposits, as is the case too within the Hampshire Basin.

Only where the Weald-Artois Anticline has been ‘unroofed’ by erosion i.e. within the Weald is the Chalk entirely absent. In this area the long south-facing scarp of the North Downs and the longer north-facing scarp of the South Downs face one another across the Weald. For similar reasons, the Chalk is largely absent from the rather smaller area to the south of the Purbeck-Wight Monocline, save for the downs immediately north of Ventnor on the Isle of Wight.

Some of the best exposures of the Chalk are where these ranges intersect the coast to produce dramatic, often vertical cliffs as at Flamborough Head, the White Cliffs of Dover, Seven Sisters, Old Harry Rocks (Purbeck) and The Needles on the Isle of Wight. The Chalk, which once extended across the English Channel, gives rise to similar cliff features on the French coast.