Cover photograph Heterogeneous Archaean TTG suite rocks exposed on the farm Nooitgedacht, Johannesburg Doome, South Africa. Shown are variably feldspathized agmatitic remnants of amphibolite in a host matrix consisting mainly of biotite-trondhjemite gneiss (Anhaeusseur, 1999). Length of the scale (magnetic susceptibility meter) is 19.5 cm. |