Algoman orogeny geophysical measurements on the greenstone belts in Canada, suggest the metavolcanic and metasedimentary rocks of the belts project downward at least a few kilometers. The action of metamorphism on the border between granite and gneiss bodies produces a succession of metamorphosed volcanic and sedimentary rocks called greenstone belts. Most Archean volcanic rocks are concentrated within greenstone belts; the green color comes from minerals, such as chlorite, epidote and actinolite that formed during metamorphism. After metamorphism occurred, these rocks were folded and faulted into a system of mountains by the Algoman orogeny. The volcanic beds are thick. About the greenstone belt
Pan-African orogeny Pan-African orogeny The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago. This orogeny is also known as the Pan-Gondwanan or Saldanian Orogeny. The Pan-African orogeny and the Grenville orogeny are the largest known systems of orogenies on Earth. The sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust. The term "Pan-African" was coined by for a tectono-thermal event at about 500 Ma when