Alum Shales
Alum Shales Overview
The term Alum Shale was introduced over three hundred years ago to refer to the particular parts of the Late Cambrian shales from which alum salt was extracted. The name Alum Shale Formation is used for the entire lithostratigraphic unit throughout Scandinavia.
Since the 20th century, the Scandinavian alum shales have been characterized as having remarkable uranium content. The shales have also been shown to contain unusually high concentrations of other trace elements, particularly vanadium, molybdenum, nickel and other rare elements.
The discovery over three hundred and fifty years ago led to the development of one of Sweden’s earliest major industries (Rinman 1788). Mining started in 1637 in Skâne and this was followed by the establishment of mining and extraction industries in several other areas.
Today, Sweden’s black shales contain:
- significant levels of organic carbon content, also known as kerogen, of up to 20%, which has been exploited in history for fuel and for oil production, and
- unusually high concentrations of metals, notably vanadium, uranium, molybdenum, and nickel.