Kjell Billström: U-Pb dating of Cu-Au-Fe oxide ore deposits in Norrbotten county, Sweden

A less well constrained ore type occurs in N. Sweden; mineralizations containing iron oxides together with Cu-sulphides and gold. Similar ore types occur in e.g. Australia, where the presence of some giant ores (Earnest Henry and Olympic Dam), has boasted the research on this ore type. Coupled to the mineralization events in Norrbotten is the presence of alteration minerals, like K-feldspar, tourmaline, scapolite, albite etc. Titanite is also occasionally part of the alteration parageneses, and since this mineral is well suited for radiometric dating, one may infer that the U-Pb age of titanite from a specific mineralization is a good approximation of its age. Sofar, the age data show that mineralization events took place basically at two stages; at 1880-1850 and 1790-1760 million years ago, respectively.