View Full Version : The Martian Ice-Filled, Oyster Shell-Shaped Crater (HiRISE Images)

2008-Oct-21, 08:10 PM
This striking view of the Martian surface shows a stark contrast (false colour) between ice deposits and layered deposits (composed mainly of ice, rock and regolith) on the edge of the polar ice cap. In the centre, there is a lone crater, approximately 200 meters in diameter, collecting a basinful of ice. The ice is [...]

More... (http://www.universetoday.com/2008/10/21/the-martian-ice-filled-oyster-shell-shaped-crater-hirise-images/)

2008-Oct-22, 12:36 AM
Yum, oysters!

2008-Oct-22, 01:24 AM
Yum, oysters!

You can have mine Kai. But if you aren't going to eat those fried clams...

Why wouldn't the oyster shape be formed like those lakes in Canada and Alaska formed by sunlight only heating one side?

2008-Oct-22, 01:28 AM
Would the meteorite coming in at an extreme angle affect the shape of the crater?

2008-Oct-22, 01:30 AM
the resurfacing rate seems pretty rapid. In this case, it is also believed the ice deposits in the crater are only 10,000 years old....So much for Mars being a "dead" planet, then. As seen with the dynamic avalanche processes and rolling boulders, Mars is far from being geologically inactive…

Ice forming only 10,000 years ago, why, only last year a boulder rolled down a slope in Tharsis. This planet is seething with activity, let me tell you!

2008-Oct-22, 02:04 AM
Would the meteorite coming in at an extreme angle affect the shape of the crater?

From what I recall of previous discussions, extreme angle might net you a symmetric butterfly ejecta with a (2-fold) symmetric ellipsoidal crater.

Other moderate angles still yield circular craters

It's hard to get asymmetry I think from a single impact, unless the land was somehow asymmetric in strength.

2008-Oct-22, 02:15 AM
That shape has got to be post impact. Which way is north in these pictures?