Arkley, S. L. B., Browne, M. A. E., Albornoz-Parra, L. J. and Barron, H. F. 2011. East Dumbartonshire Geodiversity Audit. British Geological Survey Open Report, OR/09/19. 265pp.
EDC 4: Lenzie–Torphichen Dyke, Lenzie
Grid reference:
Site type: Natural exposure
Site ownership: Not known
Current use: Private Country
Field surveyor: Sarah Arkley & Luis Albornoz-Parra
Current geological designations: None
Date visited: 5th March 2009
Site map
Summary description
The topographic expression and composition of the Lenzie–Torphichen Dyke can be explored at this site at Claddens on the east side of Lenzie. This and the nearby Claddens Dyke to the south are significant E–W trending, quartz-microgabbro, sub-vertical sheet-like intrusions which traverse across East Dunbartonshire. The dykes cut through the Carboniferous sedimentary rocks of the Midland Valley.
They, with a few other quartz-microgabbro dykes stretch east-west 10's km with little interruption across East Dunbartonshire. The dykes are commonly 20–30 m thick, although have been recorded up to 45 m (Forsyth et al, 1996). The dykes are generally regarded as feeders to the sills (such as those exposed in EDC1, EDC2 and EDC3) and as such their age is assumed to be same (290–295 Ma).
Some have been quarried but generally the much thicker sills were exploited as a resource. Good site to show how geology influences the shape of the landscape – resistant nature of the microgabbro dyke forms a long, narrow, wall-like ridge.
The high ground, formed by the resistant nature of the microgabbro, appears to have influenced the course of the river at this point and the nature of the channel. Also forms a distinctive ridge farther east (1.25 km) which has been used to build the road on. Exposure of the dyke materials are limited, lake below south side but to west of river there are outcrops either side of road which could be cleaned up ('old quarry' recorded here on 1922/23 OS map). Weir positioned where dyke crosses river — humans following natural barrier. Info in Robertson, 1937, p101 and Clough, 1911, p158. If any leaflets were to be written on the Strath Kelvin Railway Path, could include some info on this site.
EDC 4: Stratigraphy and rock types
Age: Upper Carboniferous Formation: Lenzie–Torphichen Dyke
Rock type: Quartz-microgabbro
Assessment of site value
Access and safety
Aspect/Description
Road access and parking Parking probably best within the housing estates in the south-western part of Kirkintilloch, either walk eastwards along the road (B757) to the site or join the course of the old railway line ('StrathKelvin Railway Path') and find the site from the north.
Safety of access Construction work is currently taking places in the western part of the site. South of the site, part of the land is flooded and has very boggy areas, otherwise rough open country.
Safety of exposure Small natural exposures are well-jointed but there is little risk of material falling. Man-made exposures are sub-vertical and recent, these should be checked for any loose material higher up the faces and cleaned up for access to fresh sections.
Permission to visit No permission sought
Current condition Good
Current conflicting activities Construction work in the western part of the site
Restricting conditions None
Nature of exposure Natural and man-made outcrops along
Culture, heritage & economic
Historic, archaeological & literary associations None known. Rating: 0.
Aesthetic landscape Mainly farmland. Dyke forms prominent ridge over several km's. Rating: 3.
History of earth sciences None known. Rating: 0.
Economic geology None recorded. Rating: 0.
EDC 4: Geoscientific merit
Total Geoscientific merit score 29
Current site value
Community On the other side of the river to the Strath Kelvin Railway Path which seems popular with locals. Footbridge at site. Rating: 9.
Education The dyke is a good example of how a rock which is more resistant to weathering and erosion than the surrounding material forms a positive feature on our landscape; reading the landscape. Rating: 6.
Fragility and potential use of the site
Fragility Development. Construction work ongoing in the western part of the site.
Potential use: School, On-site Interpretation, Geotrail
Geodiversity value
Of the several east-west trending dykes which traverse across East Dunbartonshire this site best reveals the composition and the influence of such igneous intrusions on the present day landscape. Rating: 4.