Geology of the Alresford district : sheet description for the British Geological Survey 1:50 000 Series Sheet 300 Alresford (England and Wales)

Abstract

Known more for its literary connections with Jane Austen and the gardens of the naturalist Gilbert White at Selborne, the Alresford district’s typically gentile English countryside seen in the Alresford district is fundamentally a product of the underlying geology. Commencing in the east, a journey westwards begins on the low lying sandy heaths and heavy clay pastureland around Bordon and Woolmer Forest, developed from the Lower Cretaceous sands and clays. Further south-east around Petersfield, the characteristic ridge and vale country is founded on the alternating sands and clays of the Lower Cretaceous Hythe and Sandgate formations. R ising steeply above the lowlands is the indented and landslipped Upper Greensand scarp, behind which the land slopes gently down to small villages such as Selborne and East Worldham before rising steeply again up the Chalk escarpment which forms perhaps the most striking feature. This scarp, running north–south across the sheet district effectively divides the region into two. Above the scarp the high hills capped by clay-with-flint around Medstead and Four Marks gently descend eastward down the long gentle dip slopes of the Chalk to the headwaters of the Itchen around New Alresford. The majority of the East Hampshire Downs with its dry valleys and gently rolling hills is underlain by the Chalk. T he landscape seen today is the result of a very long geological history which stretches back to the Early Jurassic and beyond. The rocks at surface and those beneath the district give valuable information for the understanding of such major earth history events as the opening of the Atlantic and the Channel Basin, the drowning of most of Europe during the Cretaceous Period, the Alpine earth movements and the wide climatic variations in our most recent past. T hese events have also created the conditions for the development of oil and gas and their entrapment in the rocks at depth, a feature which manifests itself in the ‘nodding donkeys’ pumping oil to the surface at places such as Humbly Grove just to the north of the district