Broad valley of one of the tributaries of the Quango river in the upper stream. The valley carved in the Upper Cretaceous red sandstone. The characteristic feature is a lack of coarse clastic material on the bottom of the valley. The network of faults perpendicular to the bottom of the valleys plays important role in valley formation. These faults are “cutting” the stream channel into elevated and subsided blocks up to a kilometer long. The low or subsided blocks form depressions or “traps” up to 10 meters deep that collect gravel material during the rainy season. This gravel material is notably enriched in heavy minerals. Photo and comments by Oleg Khotylev, Moscow State University.