Sulfur-mania hits Science

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Jess Adkins, Guillaume Paris, and I have not one but TWO articles published in this week’s edition of Science. The first is a collaboration with Sean Crowe and others, to measure the δ34S of trace sulfate in Lake Matano, an analog for the Archean oceans. We argue that low sulfate concentrations yield small apparent fractionations between sulfate and pyrite, but not for the reason previously thought. Its not that the biologic fractionation disappears, it’s that sulfate is completely consumed thus the fractionation is not expressed. The second paper is work done entirely here at Caltech, along with colleague Woody Fischer. We’ve made the first reliable measurements of CAS in Archean rocks, using our new ICP-MS technique to study rocks from the Campbellrand platform of South Africa. We show that the sulfate preserved in these rocks (which we assume represents Archean seawater sulfate) has a positive Δ33S anomaly, opposite what everyone has been assuming. This means many of the models out there for how mass-independent anomalies get generated must be incorrect. There is a third article on sulfur in this same issue from James Farquhar’s group. Somebody at Science must be feeling the sulfur love...

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