Youngest Lava Flows on Mars Are 20 to 200 Million Years Old
From;
http://www.universetoday.com/am/publish/creating_methane_life_volcanoes.html
“Methane -- which can be created naturally by volcanic eruptions or produced by primitive life -- thus may be a missing piece of the puzzle to finding out if organic remnants might once have sustained a primordial Mars. The last period of active volcanism on Mars is well before the last 300 years that methane can survive in the martian atmosphere of today. University of Buffalo volcanologist, Tracy Gregg, told Astrobiology Magazine, "the youngest surficial activity discovered to date (and it's probably 1 million years old, which would be considered quite young, and possibly "active" on Mars) is in a region that contains no large volcanic structures of any kind." Mars' gigantic volcano Mons Olympus was active until 100 million years ago.”
From;
http://www.geolsoc.org.uk/template.cfm?name=MarsMons
“He concludes that the lava could have emerged from Olympus Mons less than 10 million years ago. "The realisation that there has been recent volcanic activity is slowly seeping into the scientific community," says John Bridges, an expert in Martian meteorites at the Open University in Milton Keynes, UK. Wilson thinks the volcanoes are dormant rather than dead, and that they follow cyclical patterns of activity. The 10 volcanoes on Mars are so large that magma must flow into their chambers extremely quickly- any slower and the molten rock would solidify before the chamber was full. Given the rate that magma is produced within the planet, this could happen only once every 100 million years, Wilson says.
He estimates that the Martian volcanoes' active periods last just 1 million years, meaning that they spend 99 per cent of their time dormant. That would explain why we have not seen any activity in the past few decades of observing the planet, he says.”
From;
http://66.102.7.104/search?q=cache:....html+Active+Martian+Volcanoes&hl=en&ie=UTF-8
“Age
Like the Moon, volcanism on Mars is very old. The mare-like plains on Mars are the same age as the lunar mare, roughly 3 to 3.5 billion years old. However, volcanism lasted much longer on Mars than on the Moon. It also seems to have changed over time. Volcanism in the highland paterae and mare-like plains on Mars stopped 3 billion years ago, but some of the smaller shields and cones erupted only 2 billion years ago. The giant shield volcanoes are even younger. These volcanoes formed between 1 and 2 billion years ago. The youngest lava flows on Olympus Mons are only 20 to 200 million years old. These flows are very small, however, and they probably represent the last gasp of martian volcanism. Thus, the odds of finding an active volcano on Mars today are very small.”
No wait, I think Olympus Mons just blew it's top!
