Muckle Burn, Clunas
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Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Quaternary of Scotland | Favourable | — | 2009-07-14 |
Geology & landscape
Rock Type: Conglomerate, Granite, Quartzite
Landscape processes: Volcanic / Igneous
Description
Muckle Burn, Clunas Muckle Burn, Clunas is a small site situated 10 miles south of Nairn. It provides an exceptionally fine illustration of the effects of parent material on rock weathering and resulting clay mineral formation. The bedrock is a conglomerate comprising a mixture of boulders of various rock types. Selective weathering shows particularly well in the sharp contrast between boulders of quartzite and metamorphosed (altered) grit which are hard and largely unweathered, and those of granite and granulite which are totally decomposed. The granite and granulite contains feldspars, a common type of rock-forming mineral, which (apart from microcline), have weathered directly to montmorillonite (a calcium-rich clay), while muscovite mica has weathered to kaolin (a type of clay). The stability sequence of the primary minerals differs from the order that most commonly occurs, reflecting in part the distinctive alkaline conditions in which the weathering occurred. Overall, Muckle Burn is an excellent site demonstrating differential weathering in an unusual case where several different rock types are present in a single locality.