Re: Today's Mars Odyssey image
Mars is covered in rounded "domes" that are eroded hills. They often have a skirt or apron of debris that has flowed off them over the millennia. This is a topic of serious research at present into ice-related creep od debris aprons on Mars.
Don't mention the phrase "pressure dome" or you'll see my blood pressure rise and something will start to vent :-)
Stick to geology, and you'll be OK.