Oh, that’s exciting. I didn’t know there were any New Testament texts, even fragmentary ones at Qumran. I was citing the date for the oldest complete manuscripts.
Mousing around a bit, I found this explanation in Wikipedia(Link) (which is no authority either!) which says that the fragment, which is only about the size of a postage stamp and has less than 20 legible letters on it, only "might" be from Mark, and only "might" be that early.
Of course, discoverer Thiede argues otherwise; there are pro's and con's elsewhere on the Internet; and controversy will never cease!