| Computer Code: |
AMP |
Preferred Map Code: |
notEntered |
| Status Code: |
Index Level |
| Age range: |
Paleoproterozoic Era (AL)
— Paleoproterozoic Era (AL) |
| Lithological Description: |
[Obsolete: use BMP] Comprises the Mg-rich members of the Scourie Dyke Swarm. The dykes of the Subswarm are most abundant within the Lewisian Gneiss Complex in the Assynt region, and they typically have a broadly east-west trend.The dykes of the Subswarm are picritic and have the primary mineralogy olivine - orthopyroxene - clinopyroxene - plagioclase - phlogopite - chromite, although most have undergone amphibolite-facies metamorphism with replacement of the majority of the primary minerals. |
| Definition of Lower Boundary: |
Contacts are cross-cutting and have been modified by subsequent metamorphism. |
| Definition of Upper Boundary: |
N/A. |
| Thickness: |
From about 50 cm to 50 m thick. |
| Geographical Limits: |
As part of the Lewisian Gneiss Complex, the dykes only occur within it. They have only been mapped as a separate subswarm in the Assynt area (between Loch Laxford in the north and Loch Lurgainn in the south). |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Occur in the Lewisian Gneiss Complex of Assynt, of which the most well-studied examples are at Lochs Beannach [NC 145 264], and Leothaid [NC 144 227]. Tarney, 1973; Tarney & Weaver, 1987. |
| Reference(s): |
| Tarney, J. and Weaver, B L. 1987. Mineralogy, petrology and geochemistry of the Scourie dykes: petrogenesis and crystallization processes in dykes intruded at depth. p. 217-233 in Evolution of the Lewisian and Comparable Precambrian High Grade Terrains. Park, R.G. and Tarney, J. (eds.) Geological Society Special Publication No. 27. |
| Tarney, J. 1973. The Scourie Dyke Suite and the nature of the Inverian event in Assynt. 105-117 in Park, R G and Tarney, J (editors), The Early Precambrian of Scotland and related rocks of Greenland. [University of Keele.] |
| Weaver, B L and Tarney, J. 1981. The Scourie Dyke Suite: Petrogenesis and Geotechnical Nature of the Proterozoic Sub-Continental Mantle. Contributions to Mineralogy and Petrology, Vol.78, 175-188. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S101
S102
S107
S108
|
