West Rigg Open Cutting
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Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| NY911391 | — | Favourable | 4.74 | 2022-11-20 |
Geology & landscape
Rock Type: Limestone
Description
Area, 4.8 ha. 11.9 ac. Description West Rigg Open Cutting provides an excellent illustration of the formation of iron ore by replacement and oxidation and many trial workings for lead and fluorite can be seen on the central vein. At this site the Slitt Vein, which is over 20 kilometres long and trends just south of east, is exposed in the great Limestone. The vein consists of quartz with minor fluorite and galena but not in payable amounts. Adjacent to the vein the entire thickness of the great Limestone was replaced by mineralisation for a distance of several metres. The mineraling fluids were iron rich and the limestone was replaced by the iron carbonates, siderite and ankerite, which were subsequently oxidised to a Bilbao type goethite ore with over 40 percent iron content. The replacement flats have now been quarried leaving the vein standing as a wall like rib in the centre of the cutting. Further from the vein replacement was confined to one horizon for a lateral distance of 60m and a small exposure illustrating this can still be seen in the north wall of the cutting. Other Information 1. This site has been identified as of national importance in the Geological Conservation Review. * Under Section 23 of the National Parks and Access to the Countryside Act, 1949.