Lea Larks

Site of Special Scientific Interest · 54.9957, -4.2456

Condition (NatureScot)

Favourable (1)
UnitFeatureConditionArea (ha)Assessed
F1 Caledonian Igneous Favourable 2005-03-31

Geology & landscape

Rock Type: Granite

Landscape processes: Volcanic / Igneous

Description

LEA LARKS Lea Larks forms part of the Cairnsmore of Fleet granite massif and lies 12km north of Gatehouse of Fleet. The exposed crags at Lea Larks provide a good example of Caledonian igneous rock. The Cairnsmore of Fleet granite is the only entirely peraluminous or ‘S-type’ granite in the Scottish Newer Granites. It is the most felsic of the concentrically zoned plutons in the Southern Uplands and has the most limited compositional variation found in that group. The crags at Lea Larks provide good exposure of the fine-grained biotite-muscovite granite that forms the centre of the pluton. The highly peraluminous character of the rock is reflected in the occasional presence of garnet and, geochemically the rock is characterised by notably high strontium initial ratios. Geochemical and isotopic affinities with granites in the Lake District make this pluton important for research purposes and have implications for palaeotectonic reconstructions.