It is widely accepted that most Archaean granite–greenstones are dominated by TTG, although Late Archaean terranes, such as in the Yilgarn Craton, are dominated by potassium-rich granitoid rocks that are derived through remelting of older felsic TTG-dominated crust.
The earthquake occurred within the Utsalik domain, which consists mainly of Archean granitic and granodioritic rocks.
It is found crystallizing in the massive metasedimentary rock, sanbornite, which is found near granodiorite intrusions in Fresno and Mariposa counties, California.
The closest occurrence of such rocks can only be found in the Sarrazac massif 25 kilometers farther to the eastsoutheast (near Saint-Paul-la-Roche, Jumilhac-le-Grand and Sarrazac), their geological setting being very different to that of the local granodiorite.
Radiometric dating of the cooling ages of the Cathedral Peak Granodiorite yielded 88.1 ± 0.2 down to 87.0 ± 0.7 million years BP, i.e. Coniacian.
It consists of brown granodiorite and supports a relatively luxuriant vegetation of lichens and mosses, along with nests of Snow Petrels and Wilson's Petrels.
The study showed a close resemblance to rock from a small granodiorite quarry at Gebel Tingar on the west bank of the Nile, west of Elephantine in the region of Aswan; the pink vein running across the upper part of the Rosetta Stone was also noted as typical of granodiorite from this region.
The geology of the area includes a rock called Shannons Flat Granodiorite.