The key finding of this report is that tochilinite, rather than being a mineralogical curiosity, is exceptionally abundant at several sites on the Iberia Abyssal Plain. This is especially true in Hole 1068A, where tochilinite achieves the status of a rock-forming mineral over a drilling interval of at least 20 m. As such, it appears to be a major sink for S in the upper portions of many Iberia Abyssal Plain serpentinites and will be important in evaluating S budgets during serpentinization of the vast exposures of peridotite beneath the Iberia Abyssal Plain (e.g., Alt and Shanks, 1998).