Portland Sand Formation

Portland Sand Formation
Stratigraphic range: Tithonian, 152 Ma
TypeGroup
Unit ofPortland Group
UnderliesPortland Stone Formation
OverliesKimmeridge Clay Formation
Thicknessup to 40 metres (130 ft)
Lithology
PrimaryDolomite
OtherSiltstone, limestone and sandstone
Location
RegionEngland
Country UK
ExtentDorset
Type section
Named forIsle of Portland
LocationClay Ope, West Weare Cliff, Isle of Portland
Thickness at type section30 m

The Portland Sand Formation is a limestone formation from the Tithonian stage of the Jurassic period on the Isle of Portland, Dorset, England.[1] The formation is made up largely of dolomites but includes siltstones and fine-grained sandstones in its lower parts.[2] It is a sub unit of the Portland Group.[3]

  1. ^ British Geological Survey. "Portland Sand Formation". BGS Lexicon of Named Rock Units. Retrieved 29 June 2020.
  2. ^ Barton et al., 2011 Geology of south Dorset and south-east Devon and its World Heritage Coast. Special memoir of the British Geological Survey. Sheets 328, 341/2, 342/3 and parts of 326/340, 327, 329 and 339 (England and Wales)
  3. ^ Callomon, J H and Cope, J C W. 1995. The Jurassic geology of Dorset. 51-103 in Taylor, P D (Editor), Field Geology of the British Jurassic. (Bath: The Geological Society.)