[meteorite-list] "Secondary" craters on Mars and Carancas

[E.P. Grondine]

Hi all - 

Speaking of the small crater at Carancas, a prominent
theory put forward to explain the number of craters on
Mars is "secondary" craters formed by the impact of
large ejecta from "primary" impacts, i.e.:

http://hirise.lpl.arizona.edu/PSP_007059_1975

Given the energy required to form an impact crater of
any size, I am very suspicious of this hypothesis. I
can't see how any large ejecta from a "primary" impact
could reach sufficient velocity to have the energy
necessary to form these "secondary" craters, and I
think that some may be engaging in wishful thinking in
this regard. 

Given what we know of asteroids and comets, smaller
chunks of a "primary" impactor impacting at the same
time might be a more viable hypothesis. 

Any thoughts, anyone?

good hunting all, 
("d" is too close to "f" with my stroke, and "goof" is
as good a word as "good" to a spell checker.)
E.P. Grondine
Man and Impact in the Americas

 




      ____________________________________________________________________________________
You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost.  
http://tc.deals.yahoo.com/tc/blockbuster/text5.com