Ellen, R. and Callaghan, E. 2015. Geodiversity Audit of Spireslack and Mainshill Wood Surface Coal Mines. British Geological Survey Commerical Report CR/15/126. 70pp.
Spireslack Locality 6: Fault cut by dyke
NGR: [274784 630568]
| Key category of interest | Rarity | Quality |
|---|---|---|
| 1. Structural geology | 3 | 5 |
| 2. Igneous rocks | 4 | 4 |
| 3. 3D visualization | 3 | 4 |
Access: Good access to base of exposure, easily accessible from roadway.
Current safety: Little evidence of recent falling blocks observed on limestone pavement, uneven surfaces
Measures to enhance site: Flatten area at base of exposure as viewing area
Key categories in order of interest (1 = primary interest); Rarity, 5 = only example in Spireslack, 1 = many examples in Spireslack; Quality 5 = exceptional preservation in Spireslack, easy access/viewing potential 1 = average preservation in Spireslack, difficult access/viewing potential
Photograph overview with polygon boundary
© Getmapping: Licence Number UKP2006/01
Site description
Geology
At this locality a fault displaces the McDonald Limestone pavement down c. 2 m to the east. The fault displays well preserved slickenlines along the fault plane, indicating a sinistral sense of movement. A 1 m wide dolerite dyke cuts through the fault plane, thus proving the dykes that intrude the strata across Spireslack were emplaced after faulting had ceased. This is vital evidence for deciphering the geological history of the area. The same fault is observed on the scarp, providing a 3D perspective for fault networks across Spireslack.
Access and enhancement suggestions
The fault is easily accessible from existing roadways and the face is clean. A post or board indicating the direction of the equivalent fault in the scarp would aid in 3D visualisation appreciation.