Computer Code: |
CHUI |
Preferred Map Code: |
CHUI |
Status Code: |
Full |
Age range: |
Cryogenian Period (AC)
— Cryogenian Period (AC) |
Lithological Description: |
10 to 30cm-thick layers of quartzite, commonly ribbed in appearance; muscovitic semipelite typically accounts for less than 10% of the lithology, The base is gradational with the underlying part of the Beinn an Dothaidh Formation. |
Definition of Lower Boundary: |
The base is gradational with the underlying part of the Beinn an Dothaidh Formation, with an upwards change to quartzite as the dominant lithology. |
Definition of Upper Boundary: |
Abrupt change to the more uniform garnetiferous semipelite rocks of the Beinn Dorain Semipelite Formation. |
Thickness: |
c 200m thickness is observed in the Allt a'Chuirn section but is greatly thickened by the effects of folding, estimated stratigraphical thickness is in the order of 30 to 50m. |
Geographical Limits: |
The Member has a restricted occurance on the southern slopes of Beinn a' Chuirn, upper Auch Gleann. Sheet 46W (Crianlarich). |
Parent Unit: |
Beinn An Dothaidh Formation (DOTH)
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Previous Name(s): |
none recorded or not applicable
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Alternative Name(s): |
none recorded or not applicable
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Stratotypes: |
Reference Section |
Allt a'Chuirn (Beinn a'Chuirn), uppermost Auch Gleann. Details will be included in Sheet Description for Sheet 46W (Crainlarich). Presently in draft BGS internal report: Leslie et al., Progress Report on the Geology of the Tyndrum area, 2003. 1:50k Sheet 46W (Crianlarich). |
Reference(s): |
In preparation. BGS Sheet Description for Sheet 46W (Crianlarich) and 46E (Killin). |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
S004
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