So where do I find pictures of this?

http://www.cosis.net/abstracts/EGU2007/017...88baf6c8092ff18

"we propose that this smoke-like feature is an ephemeral phenomenon that was produced by volcanic activity such as fumarole or geyser. ... The process producing the phenomenon likely occurred after 1980 (it does not appear in Viking images: 385S51, 385S52, and 385S53 acquired in April of 1980)."

Ahhh, got it:
http://www.msss.com/moc_gallery/e19_r02/im...3/E2300771.html

Interesting. Good HiRISE target!

Interesting for sure, but I'm not sure that the words "ephemeral" and "smoke" are appropriate. This sure looks basic (if symmetrical) windborne dust deposition or surface wind scour of some sort, and there are lots of other mechanisms for this (for instance, how about a small meteor strike during a windstorm?)

Still, definitely worth a closer look, esp. in IR.