| has gloss | eng: Tyrrhena Patera is the central depression of a large volcano in the Mare Tyrrhenum quadrangle of Mars, located at 21.36° south latitude and 253.47° west longitude. It was named after a classical albedo feature name. Pit chains are found at the summit of Tyrrhena Patera. They are formed by collapse of material into underground voids. Since they form chains and concentric fractures that are aligned, they are probably caused by extension of the surface. Volcanic processes made the crust pull apart. Voids were formed, then material fell into them, leaving holes. It is one of the oldest volcanoes on Mars. As a consequence of its old age, Tyrrhena Patera has many radiating gullies on its slope. When it was formed, magma may have gone through frozen ground and then eruped as easily eroded ash, instead of lava flows. |