CRITERIA FOR THE PLACEMENT OF BOUNDARIES IN THE MAPPING AREA
Three types of boundary have been defined in the mapping area:
| Observed boundary |
With the closest approach being equal to or less than 5 metres. |
| Inferred boundary |
With the closest approach being between 5 and 50 metres. |
| Conjectured boundary |
With the closest approach being equal to or less than 50 metres. |
Only one major contact was exposed within the metamorphic complex, this being the boundary between the Luibean semipelitic schists and the Garbh amphibolite showing a sharp, sub vertical contact at Location 144 (NGR 81387753).
The boundary between the Torr schists and the Achlais amphibolite is observed to be gradational, so the boundary was marked at a point where the schist and amphibolite are in approximately equal proportions.
A series of minor contacts are exposed at location 212 (Caisteal na Cloinne NGR 80507587) but the relationship of these units to the main metamorphic complex is uncertain.
The nature of the boundary between the Tollie gneiss and the Garbh amphibolite is ambiguous and is discussed more fully in the stratigraphy section.
The Camas breccia and Druim breccia are believed to be unconformable on the metamorphic complex, although the boundary of the Camas breccia is only exposed at location 189 (NGR 80737630).
Overall, over the mapping area the boundaries are poorly exposed thus hampering the relationship of adjacent units being deduced with any degree of certainty.
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