Recent submarine aragonite, magnesian calcite, and hematite cements in a gravel from Islay, Scotland

Acicular and bladed aragonite and rhombic magnesian calcite cements similar in morphology to those found in modern tropical and subtropical environments occur in gravelly sediments from temperate waters off the Scottish Hebrides. The cemented gravels are associated with the wreck of a boat that sank while carrying a cargo of machinery. Since artifacts are cemented in the gravel, lithification postdates sinking of the ship in 1857. Evidence suggests that corrosion of the iron in the wreck took place, in part, in an anaerobic environment. Sulfate-reducing bacteria, abundant in such an environment, are believed to be the agents of carbonate cementation.--Journal abstract.