Week 5-Convergence Plates

Picture courtesy of the Geologic Society

I visited the Andes Mountain range which is a oceanic/continental convergence of two plates, the South American plate and the Nazca plate. The Nazca plate thrusts under the South American plate in a process called subduction. As subduction of the Nazca Plate continues, some of the sediments that accumulated on the ocean floor (together with some of the ocean crust) are scraped off and forced onto the South American Plate in a process called “obduction”. This forms a wedge, where layers of sediments and ocean crust are thrust onto the South American Plate along faults adding to the size of the continent. The folds are brought about by the compression that is a result of the collision of the two plates into the leading edge of the mountain range causing the rocks to fold.

Picture courtesy of Haiku Deck