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
Rangitata Orogeny This collision lasted for 50 million years. However, the wet sediments could not just keep piling up. After 50 million years, there was simply too much rock and a 'log jam' in the process was formed. The rocks were squeezed together as they broke and crumpled up. As the compression intensified, the strata were slowly pushed up, creating new land. The collision was also causing a great thickening of the crust, pushing the rocks down into the top of the mantle. The high pressures and temperatures of this occurrence metamorphosed the lower rocks into the Haast Schists. Rangitata Orogeny The