| Computer Code: |
SUMI |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Holocene Epoch (QH)
— Holocene Epoch (QH) |
| Lithological Description: |
Predominantly dark olive grey (5Y 3/2) to very dark greyish brown (2.5Y 3/2), very soft to soft, bioturbated to homogeneous, silty mud with sporadic shells and shell fragments. Base of unit locally marked by a very coarse, poorly sorted, carbonate gravel (shell hash) and muddy, slightly sandy and shelly sand. Coarse sandy and gravel lag on shallow marine banks. |
| Definition of Lower Boundary: |
Unconformable and commonly erosional on the Annat Bay Formation and/or older underlying glacial units. |
| Definition of Upper Boundary: |
Present-day sea bed. |
| Thickness: |
Mostly less than 5 m thick, but up to 12 m thick in outer Loch Broom, associated with a discrete sediment drift. |
| Geographical Limits: |
Predominantly recognised as partial fills in the glacially overdeepened deep-water basins landward of the Summer Isles, i.e. Tanera, Coigach, North Annat, South Annat, South-East Annat, Skerries and South Priest basins, as well as Loch Broom and inner Little Loch Broom. Also occurs as seismically unresolvable lag deposit on the shallow marine banks. |
| Parent Unit: |
Not Entered (?)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
57.8655 deg N, 05.1063 deg W. BGS vibrocore 57-06/267, between seabed and 2.06 m below seabed, inner Loch Broom (Stoker and Bradwell, in press). |
| Reference(s): |
| Stoker, M S, Bradwell, T, Howe, J A, Wilkinson, I P & McIntyre, K. 2009. Lateglacial ice-cap dynamics in NW Scotland: evidence from the fjords of the Summer Isles region. Quaternary Science Reviews, 28, 3161-3184. |
| Stoker, M S and Bradwell, T. In press. Quaternary geology of the Summer Isles region - a brief explanation of the marine environment map. Sheet Explanation of the British Geological Survey. 1:50 000 Special Sheet Summer Isles (Scotland). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
