Knockormal
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Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Ordovician Igneous | Favourable | — | 2013-03-20 |
Geology & landscape
Geological Period: Ordovician
Landscape processes: Volcanic / Igneous
Description
KNOCKORMAL Knockormal, lying less than 3km from Colmonell, illustrates the Ballantrae Complex, of Ordovician age (around 500 to 470 million years ago), which consists of three belts of pillow lavas and associated sediments, separated from each other by ultramafic intrusive rocks. The Complex shows many of the features of an obducted ophiolite although geochemical studies indicate that the various igneous rocks were generated in a variety of tectonic settings and have since been tectonically juxtaposed. The vicinity of Knockormal Farm is famous for problematical occurrences of glaucophane-schists and metapyroxenites. The formation of glaucophane-schists is thought to require a high pressure regime. Such rocks are normally associated with a subduction setting and are difficult to accommodate in the accepted obduction-dominated interepretation of the Ballantrae Complex. Mineral chemical studies on the garnet pyroxenite at Knockormal suggests it may have originated in the lower crust. These problematical occurrences provide important constraints on plate tectonic interpretations of the Ballantrae Complex.