Background
The quarry was opened between 1855 and 1895, and was worked until at least the 1920’s for road- metal; it was once regarded as one of the better sources of road-metal in East Lothian (Ewing, 1913). The analcime-basanite exposed in the quarry was originally thought to be a sill intruding into the country rock by Clough et. al. in 1910. However, a fresh phase of quarrying in the 1920’s exposed a vertical contact between tuff and basanite leading Simpson (1928) to suggest that it was in fact a volcanic plug.
Today the quarry is accessed via a muddy grass path from a gate at the junction of two roads to the west of Kidlaw Farm (ELC_20 P1). The quarry floor is overgrown by vegetation, and is uneven due to agricultural and other rubbish dumped in the pit (ELC_20 P2). The south-eastern face of the quarry is completely covered by a rubbish tip.
Volcanic Rocks
The main quarry face to the north is approximately 5 metres high, composed of a dark grey, fine- grained basanite (a silica poor, alkali rich form of basalt, associated with continental rift magmatism) displaying roughly columnar cooling joints (ELC_20 P3). The basanite is occasionally porphyritic, containing phenocrysts of olivine, augite (ELC_20 P4) and plagioclase. The groundmass contains alkali feldspars with analcime, which have been weathered out and account for the speckled nature of some of the weathered surfaces in the quarry (ELC_20 P5). The basanite also contains ultra-basic nodules (0.5–2 cm in diameter), which are interpreted as altered spinel lherzolites. The ultra-basic rocks are rich in elements such as magnesium and iron, which have been altered through hydrothermal processes (ELC_20 P6). The basanite also contains clasts of biotite granites, which are believed to be related to a Devonian age granite intrusion 500 m to the ESE of the quarry (ELC_20 P7). Agates are known to have been collected from the quarry in the past. A number of the joints running throughout the basanite are mineralized, some displaying excellent examples of quartz prisms (ELC_20 P8).
A fissile, grey — brown tuff and breccia dyke is intruded in the basanite to the west of the quarry. The dyke, and basanite adjacent to the dyke, is well jointed and mineralized. The mineral veins form impressive cross-cutting relationships (ELC_20 P9), and multiple phases of mineralisation (clay and carbonate minerals) can be identified (ELC_20 P10).
N.B. The East Lothian Guide Book mentions that small outcrops of reddish tuff can be seen upon entering the quarry — however, at time of visit, the tuff is no longer visible due to the area being overgrown and covered by tipped waste.
Access and Additional Information
Access to the site is by a gate at the junction of two minor roads to the west of Kidlaw Farm [350710 664203]. Parking is possible at Kidlaw Farm with permission from the farmer. The quarry is accessed track which leads to the quarry. The quarry face is accessible and relatively stable but due care should be taken when working beneath quarry faces. The ground of the quarry is uneven due to teh presence of tipped waste.
N.B. The Kidlaw Erratic (ELC_22) lies 170 m to the east of this site.
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