Desert varnish
Videos
Desert varnish or rock varnish is an orange-yellow to black coating found on exposed rock surfaces in arid environments. Desert varnish is approximately one micrometer thick and exhibits nanometer-sca
Desert varnish on gibber, Central Australia
Desert varnish on Bishop Tuff.
Petroglyphs carved in desert varnish at the Valley of Fire near Las Vegas, Nevada. Area shown is about one metre across.
Desert varnish at Capitol Reef National Park
Bishop Tuff
Videos
The Bishop Tuff is a welded tuff which formed 764,800 ± 600 years ago as a rhyolitic pyroclastic flow during the approximately six-day eruption that formed the Long Valley Caldera. Large outcrops of t
Desert varnish
…appears to have been observed by rovers on Mars, and if examined may contain fossilized life from Mars's wet period. Composition Desert varnish on Bishop Tuff. Originally scientists thought that the varnish was made from substances drawn out of the rocks it coats. Microscopic and microchemical observations…
Two layers of the Bishop Tuff: lower layer was from ashfall, upper layer was from the main pyroclastic flow.