Hovenweep - Tower Point Ruin

Tower Point Ruin was built overlooking the intersection of two tributary canyons of Little Ruins Canyon. Over time, gradual stream erosion and gravity-induced mass wasting have undercut the cliffs near the tower, causing large blocks of the cap-rock sandstone to tumble into the canyon. Some of the surfaces of the blocks and cliffs preserve dark streaks of desert varnish. Desert varnish is a thin, dominantly manganese mineral coating that forms on the surface of rock. Manganese-fixing bacteria living on the rock surface help trap minerals from dust and streaming water (Dorn and Oberlander, 1982; Garvey and others, 2008). Ancient carvings (pictographs) in the desert varnish heal slowly, showing that desert varnish layers build up over hundreds or even thousands of years.