Question: what type of rocks are found in the andes mountains?
Answer: The rocks run the gamut of sedimentary rocks, including: sandstones, siltstones, shales, limestones, and quartzites. Volumetrically and economically, Ordovician and Silurian shales and siltstones are probably the most important sequences (formed 500-440 million and 440-395 million years age, respectively).