Wikimedi'Òc

Hydrothermally-altered rhyolitic ash-flow tuff (Lava Creek Tuff, Middle Pleistocene, 640 ka) at Steamboat Geyser (6 August 2013) 1 (12729770834).jpg - Ser Amantio di Nicolao

Hydrothermally-altered rhyolitic ash-flow tuff (Lava Creek Tuff, Middle Pleistocene, 640 ka) at Steamboat Geyser (6 August 2013) 2 (12729288445).jpg - Ser Amantio di Nicolao

Hydrothermally-altered rhyolitic ash-flow tuff (Lava Creek Tuff, Middle Pleistocene, 640 ka) at Steamboat Geyser (6 August 2013) 3 (12729441443).jpg - Ser Amantio di Nicolao

Hydrothermally-altered rhyolitic ash-flow tuff (Lava Creek Tuff, Middle Pleistocene, 640 ka) at Steamboat Geyser (6 August 2013) 5 (12729759964).jpg - Ser Amantio di Nicolao

Hydrothermally-altered rhyolitic ash-flow tuff (Lava Creek Tuff, Middle Pleistocene, 640 ka) at Steamboat Geyser (6 August 2013) 4 (12729283315).jpg - Ser Amantio di Nicolao