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 [Obsolete Name and Code: Use DASI]
(-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. |
Gibbard, P L. 1994. Pleistocene History of the Lower Thames Valley. (Cambridge University Press.) |
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). |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E256
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