|BGS image ID: P527579|
The South Erradale bog iron ore is a good example of ore from the comparatively small pans that occur in the Loch Maree area associated with the long history of bloomeries and furnaces in the area. British Geological Survey Petrology Collection sample number MC 7359. An early analysis by Ivison Macadam of two samples of South Erradale bog iron ore are sample a, 70.88 per cent ferric oxide; 49.61 per cent metallic iron; 7.48 per cent silica. Sample b, 66.68 per cent ferric oxide; 46.67 per cent metallic iron and 8.24 per cent silica. It is thought that the deposits were so small and few that the local bog iron ores would have been exhausted in early times and that iron would have been imported from elsewhere, possibly haematite from Cumberland and clayband ironstone from Fifeshire.
|BGS image ID: P527581|
It is recorded that in 1874 Shetland produced 692 tons of bog iron ore. British Geological Survey Petrology Collection sample number MC 7361. Evidence for the earliest traces of iron-making in Scotland can be seen in the bloomeries where local bog iron ore of recent origin was smelted. They arose in several areas due to the availability of bog iron ore and a good supply of timber for charcoal making. Bog iron ore is a general term for soft, spongy and porous sedimentary deposits of impure hydrous iron oxides formed in bogs, swamps, marshes, peat mosses and shallow lakes from the chemical precipitation from iron-bearing waters and by the oxidizing action of algae, iron bacteria or the atmosphere.