Iron ore is rarely mentioned in the context of the geology of Nidderdale and district but it does exist though it is not of a type nor a quality that would make it viable in today's blast furnaces. It was found in shale beds, peat bogs and as superficial deposits resulting from glacial action and was used across the district in bloomery furnaces and early blast furnaces until around 1600AD after which it was unable to compete with other areas where there were more abundant and more accessible resources.
The diagram below shows some of the means of gaining ore that were used in earlier times in and around Nidderdale.
Carbonate Ores - Iron is present as FeCO3 - Ferrous Carbonate (Nidderdale Ores are probably of this type).
Haematite - Iron is present as Fe2O3 - Ferric Oxide
Limonite Ores - Iron is present as Fe2O3.H2O or HFeO2 - Hydrated Iron Oxides
Products of the Corrosion of Iron
Ferric Oxide - Fe2O3 - Rust - Destructive
Ferrous Oxide - FeO - Black - Protective
Ferrosoferric Oxide - Magnetite - Fe3O4 - Magnetic