The BGS Lexicon of Named Rock Units — Result Details
Chelsfield Gravel Formation
| Computer Code: | CHGR | Preferred Map Code: | symb |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Pliocene Epoch (NP) — Pliocene Epoch (NP) | ||
| Lithological Description: | Well rounded flint pebble gravels, sandy gravels, pebbly sands and sands. Lithologies similar to those in the Harwich Formation (formerly Blackheath Beds or Disturbed Blackheath Beds) from which it is thought to have been mainly derived. | ||
| Definition of Lower Boundary: | Unconformable on Upper Chalk or Thanet Sand, locally let down into dissolution hollows. Poorly exposed. | ||
| Definition of Upper Boundary: | Ground surface. | ||
| Thickness: | Variable and uncertain, not exposed. Typically 2-5 m. May be 10 m where infilling hollows or pipes in Chalk. | ||
| Geographical Limits: | The deposit extends for 500 m in the type area: other deposits occur on the Dartford (271) sheet from Knockmill [57 61] to Holly Hill [66 62]. May be present also south of the Dartford district. | ||
| Parent Unit: | Residual Deposits Group (RESID) | ||
| Previous Name(s): | Blackheath Beds [Obsolete Name and Code: Use CHGR, BLB]
(-2081)
Chelsfield Gravel [Obsolete Name and Code: Use CHGR] (-2694) Clay with Flints [Obsolete Name and Code: Use CWF, CHGR] (-3926) Disturbed Blackheath Beds (DBLB) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Slight positive feature on Chalk dip slope at Court Lodge Farm, Chelsfield; soil contains numerous well rounded black flint pebbles, generally < 3 cm diameter. | ||
| Reference(s): | |||
| Ellison, R A, Woods, M A, Allen, D J, Forster, A, Pharaoh, T C and King, C. 2004. Geology of London. Memoir of the British Geological Survey, Sheets 256 (North London), 257 (Romford), 270 (South London), 271 (Dartford) (England and Wales). | |||
| Berdinner, H C. 1936. A section at Biggin Hill Aerodrome, Kent. Proceedings of the Geologists' Association, Vol. 47, 15-21. | |||
| Whitaker, W and Davies, G M. 1920. The section at Worms Heath. Quarterly Journal of the Geological Society, Vol.75, 7-31. | |||
| Stoker, M S, McMillan, A A and Waters, C N. Quaternary Stratigraphical Chart: Southern Britain. British Geological Survey, 1 poster. | |||
| McMillan, A A, Hamblin, R J O, and Merritt, J W. 2011. A lithostratigraphical framework for onshore Quaternary and Neogene (Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03. 343pp. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E271 | |||