Answer:
IN subduction zones
Explanation:
Subduction is the important geologic process in which a tectonic plate made of dense lithospheric material melts or falls below a plate made of less-dense lithosphere at a convergent plate boundary.
Explanation from National geographic
Valleys, waterfalls, meanders, oxbow lakes, and floodplains.
Ocean fossils found on the rocky mountains are because of tectonic plates crashing.