Space/Science — HabitableZone

Space/Science » in reply to re: olivine in earth is from recent eruptions

re: olivine in earth is from recent eruptions
gbaikie — (archived)

"Since it seems pretty conclusive that there hasn't been a lot of volcanic activty on Mars recently, any olivine-bearing rocks have been exposed for a long time. "

There may not have been volcanic activity "recently", but there certainly has had impacts "recently". On earth we have small impactors which do not make this through our atmosphere (something like 30 per year which are around car sized). On Mars you would have few impacts due to the smaller size in comparison to Earth- but these bodies are more abundant at Mars distance. So you would probably get around 15 of these size impactors per year and some or most would punch through Mars' thin atmosphere. On the scale of thousands of years, you would have even larger impactors- roughly a couple hydrogen bomb size impacts per thousand years. So on longer scales of tens of thousands to hundreds of thousands, Mars has been similar to a huge nuclear war. These modest to larger impactors not only vaporize but they vaporize rock around where they hit. Plus if olivine exist in space [not sure] you also have the constant rain of pebbles and grain size material coming from space- which may only be a ton or so per year, be over tens of thousands of years in adds up.
Btw, I don't know if olivine can be created by the heat of an impactor, it make require for some reason a slower heating which occurs in volcanic rock.

Log in or register to post.

The whole thread (38 posts)