Gannister Quarry
Also within
Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| SJ869592 | — | Favourable | 1.59 | 2012-09-28 |
Geology & landscape
Mining / Industrial: Quarry · Geological Period: Carboniferous
Description
Area, 1.94 ha. 4.8 ac. Description Gannister Quarry provides valuable exposures of a sequence of shales, sandstones and gannister layers, formed during the Namrurian mid Carboniferous period of geological history, about 320 million years ago. Gannisters are very pure sandstones formed almost entirely of silica SiO2. They were formerly of economic importance, primarily as the raw materials for the manufacture of silica bricks for furnace linings but also used for glass and ceramics manufacture. These rocks contain fossil marine animals of types which indicate the deposits accumulated near to the sea shore. This is also suggested by the predominance of sandstones in the sequence. The probable existence, during Namurian times, of a shoreline nearby is geologically significant as it is evidence of the position of a land area known as 'St George’s Land' which acted as a source of sediment at that time. This is an important aspect of our understanding of the geological evolution of Britain during the Namurian Period.