What would you call this style of clothing?

Okay, you have the "preppy" style (lacoste, bananna republic, etc... or in a 13 year olds case Abercrombie and Hollister) and you have the "punk", blah blah blah. Im not one to "label", but I have no idea what Mary-Kate Olsen or Nicole Richie's style would be called. 70's vintage... or something? Help me out here.