Board Thread:General discussion/@comment-74.205.162.254-20121221215839/@comment-5756858-20121226235900

"After 3 seconds, the mark will detonate, dealing physical damage equal to 100% of Zed's attack damage plus a percentage of all magic and physical damage dealt to the target by Zed and his shadows while the mark was active."

So, yes, they are, as long as they don't deal true damage I guess.