The BGS Lexicon of Named Rock Units — Result Details

Dartford Silt Member

Computer Code: DASI Preferred Map Code: notEntered
Status Code: Full
Age range: Quaternary Period (Q) — Quaternary Period (Q)
Lithological Description: Varies from silt to clay, commonly yellow-brown. Origin uncertain. Commonly includes a high percentage of wind-blown, silt-sized quartz (possibly loess). May also be "overbank" deposits or solifluction deposits. [Generic description].
Definition of Lower Boundary: Mainly overlies or incises Boyn Hill Gravel Member or bedrock.
Definition of Upper Boundary: At Surface or overlain by head deposits.
Thickness: 0.3 to 4.6m, commonly about 3m.
Geographical Limits: Dartford District.
Parent Unit: Maidenhead Formation (MNHD)
Previous Name(s): Dartford Silt (-2741)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Dartford Heath. Ellison et al., 2004. 
Reference(s):
Bowen, D Q. 1999. A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report, No. 23. 
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). 
Gibbard, P L. 1994. Pleistocene History of the Lower Thames Valley. (Cambridge University Press.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E256