Hartcliff Rocks Quarry
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Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| ST533662 | — | Unfavourable Declining | 1.5 | 2023-01-18 |
Geology & landscape
Mining / Industrial: Quarry · Geological Period: Carboniferous, Triassic · Rock Type: Carboniferous Limestone, Conglomerate, Limestone
Description
Description Hartcliff Rocks Quarry provides excellent exposures of Triassic Dolomitic Conglomerate unconformably overlying Carboniferous Limestone. Both rock types have undergone extensive replacement by siliceous iron oxides. The exposures and spoil heaps clearly demonstrate how the iron mineralisation is preferentially hosted by the more porous and permeable conglomerate. The iron ores, which are principally goethite and haematite, are also concentrated along the plane of the unconformity. Disseminated pink barite is also present in the iron rich horizons, while calcite barite veins and neptunian dykes can be clearly seen to cut across the iron mineralisation. The site superbly demonstrates the disseminated type of iron mineralisation that is commonly found in the Dolomitic Conglomerate of the Bristol District and is particularly valuable in demonstrating the lateral variation in intensity of the mineralisation.