Abstract
Authigenic titanium minerals-rutile, anatase, brookite, and sphene-are recorded in two sequences of sedimentary rocks of Proterozoic age, the Visingsoe Group and the Dala Sandstone Formation. Due to diagenesis of the Visingsoe Group and diagenesis to low-grade metamorphism of the Dala Sandstone Formation, the unstable titanium-bearing minerals, mostly biotite and ilmenite, released their titanium. This titanium was involved in the formation of different titanium minerals either on the altered detrital particles, mostly biotite and ilmenite, or in pore spaces. These titanium minerals are often found to attack silicate minerals such as quartz and feldspars. Due to higher temperature and pressure, euhedral sphene and rutile are more common in the Dala Sandstone Formation.--Modified journal abstract.
