Odin Sough outfall, Castleton, Derbyshire

The orange staining on the stream bed is due to iron-rich water emerging from Odin Sough just to the left of centre. The sough drains water from the old Odin lead mine about 1.6 km away to the west. The mine worked lead ore from veins in the Carboniferous Limestone close to the junction with the overlying dark, pyritic Edale Shales, and the sough itself is driven in the latter for most of its length. It is the oxidation and solution of pyrite (iron sulphide) in the shales and its reprecipitation as ferric hydroxide which causes the orange colouring.

The main stream on the right of the photo rises near Hollins Cross, and has no contact with mine workings. The circular culvert in the distance merely channels the stream beneath a farm entrance track.

A closer view of the sough tail is here:
www.ipernity.com/doc/earthwatcher/39023940