Apologies, had a friend come over to visit and missed the posts where people wanted to find out about the sulfur.
During today's press conference, archived on Real Media on the cspan site (look in the "latest video" column for the link:
http://www.cspan.org/ Can't remember how many minutes in, but Steve Squires stated that right before the conference started they'd just gotten the first spectral data from the outcrop and it was full of sulfur, they were still analyzing the data.
Higher in sulfur content......
That is a major qualifier and must be taken notice of.
These rocks are not sulfur, as may have been implied by previous postings.
They only have a higher sulfur content than the surrounding soil.
To me, that only implies a more recent origin.