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 15: Calmy Limestone
NGR: [275406 630674]
| Key category of interest | Rarity | Quality |
|---|---|---|
| 1. Stratigraphy | 3 | 5 |
| 2. Sedimentary rocks | 3 | 3 |
Access: Good access to exposure, easily accessible from roadway.
Current safety: Potential for falling blocks at margins of outcrop extent and marshy ground/potential for flooding underfoot at base of exposure.
Measures to enhance site: Create viewing platform and rope off edges of exposure
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
The Calmy Limestone, belonging to the Upper Limestone Formation, is a laterally persistent marine limestone correlatable across the Central Belt of Scotland. At this locality it is exposed in a 15 m high section at the eastern edge of the Spireslack void. The Calmy Limestone, overlying the Gill Coal at this location, is composed of an interbedded sequence of 1.5–2 m thick marine limestones and mudstones. The limestones were deposited in warm, shallow clear waters during maximum flooding events associated with sea level fluctuations at the time. This locality provides an excellent section through the Calmy Limestone sequence, composed of 3 key beds of pale grey, fossil poor, fine-grained, massive limestones. The underlying Gill Coal contains nodules of pyrite throughout, formed in oxygen starved conditions whilst the coal was forming.
Access and enhancement suggestions
Access is good, but potential for loose blocks falling from above prevents any close approach. The base of the area is liable to flooding, therefore flood prevention measures or a raised walkway would allow easier access to the limestones.