Does it argue against vitrification when you read the highlights of the conclusion? Really? See post 4638 if you are unsure.
It doesn't argue strongly one way or the other, as the results were inconclusive. It certainly doesn't argue in favor of melting rocks into place, since as the article itself says:
"This indicates that the compounds in the surface layer were most likely added. Other stone types may be comparable, but they cannot have formed naturally in the layer"
That sounds more like it favors abe's view.