Computer Code: |
ARPS |
Preferred Map Code: |
ArPs |
Status Code: |
Full |
Age range: |
Neoproterozoic Era (AZ)
— Neoproterozoic Era (AZ) |
Lithological Description: |
Medium- to thickly-bedded psammite and semipelite; coastal section contains a basal quartzite member; elsewhere locally contains units of 'boulder bed', a metadiamicton with sparse cobble clasts of granitic and metasedimentary rocks. |
Definition of Lower Boundary: |
Base faulted out in coast section; elsewhere rapid transition is inferred from graphitic semipelites and limestones of Fordyce Limestone Formation. |
Definition of Upper Boundary: |
Change from interbedded psammite and semipelite to thick-bedded quartzite. |
Thickness: |
Increases from c.75m at Newton [542 619] to c.200m at coast, where it is partly repeated by a ductile thrust of the Keith Shear Zone. |
Geographical Limits: |
Coast section from Red Haven to 150m southeast of Foul Hole [NJ 563 663-579 666]; extends southwards as far as Newpark [NJ 530 606]. |
Parent Unit: |
Islay Subgroup (DBIS)
|
Previous Name(s): |
Durn Hill Quartzite [Obsolete Name and Code: Use ARPS]
(-26)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Section |
Coastal section from to Red Haven to 150m south-east of Foul Hole. |
Reference(s): |
Harris, A L, Haselock, P J, Kennedy, M J and Mendum, J R, 1994. The Dalradian Supergroup in Scotland, Shetland and Ireland. 33-53 in Gibbons, W E and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, London, No.22. |
Read, H H, 1923. Geology of the country around Banff, Huntly and Turriff, Lower Banffshire and north-west Aberdeenshire. Memoir of the Geological Survey, Scotland Sheets 86 and 96 (Scotland). |
Stephenson, D and Gould, D. 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. |
Spencer, A M and Pitcher, W S, 1968. Occurrence of the Portaskaig Tillite in north-east Scotland. Proceedings of the Geological Society of London, No.1650, 195-198. |
Stephenson, D, et al. 1993. Stratigraphy and correlation of the Dalradian rocks of the East Grampian Project area. British Geological Survey Technical Report WA/93/91. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
S096
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