| Computer Code: |
BLWR |
Preferred Map Code: |
SYMB |
| Status Code: |
Full |
| Age range: |
Neoproterozoic Era (AZ)
— Neoproterozoic Era (AZ) |
| Lithological Description: |
Greywacke grits, phyllitic pelites and andalusite bearing semipelites; quartzites; basic and ultramafic meta volcanic rocks. |
| Definition of Lower Boundary: |
Faults and shear-zones of the Portsoy Lineament truncate base of formation along the whole of its strike length. |
| Definition of Upper Boundary: |
Base of highly magnetic biotite-andalusite-schist easily mapped and/or traced by magnetometer between NJ 405 312 and NJ 441 351 (the Garnel Burn Member of the Clashindarroch Formation). |
| Thickness: |
2500 m (based on outcrop width only - no allowance for probable folding). |
| Geographical Limits: |
Between the Black Water and the headwaters of the River Deveron and on both sides of the Deveron Valley between Bridgend and Lynebain in an outcrop up to 3km wide. Cabrach area, Moray District. 1:50 000 Sheets 75E, 85E and 86W. |
| Parent Unit: |
Argyll Group (ARGY)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Partial Type Section |
Black Water River section between east margin of Blackwater Gabbro and junction with River Deveron. |
| Partial Type Section |
Burn of Hillock from 200m above Hillock of Echt Farm to junction with Garnel Burn tributary. |
| Reference(s): |
| Fettes, D J, Munro, M. 1989. Age of the Blackwater mafic and ultramafic intrusion, Banffshire. Scottish Journal of Geology, vol. 25, 105-111. |
| Fettes, D J, Lesley, A G, Stephenson, D and Kimbell, S F, 1991. Disruption of Dalradian stratigarphy along the Portsey Lineament from new geological and magnetic surveys. Scottish Journal of Geology, Vol.27, 57-73. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S075
S086
|
