| Portland Sand Formation | |
|---|---|
| Stratigraphic range: Tithonian, | |
| Type | Group |
| Unit of | Portland Group |
| Underlies | Portland Stone Formation |
| Overlies | Kimmeridge Clay Formation |
| Thickness | up to 40 metres (130 ft) |
| Lithology | |
| Primary | Dolomite |
| Other | Siltstone, limestone and sandstone |
| Location | |
| Region | England |
| Country |  UK |
| Extent | Dorset |
| Type section | |
| Named for | Isle of Portland |
| Location | Clay Ope, West Weare Cliff, Isle of Portland |
| Thickness at type section | 30 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]
- ^ British Geological Survey. "Portland Sand Formation". BGS Lexicon of Named Rock Units. Retrieved 29 June 2020.
- ^ 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)
- ^ 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.)