A young porcellanite occurrence from the Southwest Indian Ridge

• Published in: Marine Geology
• Main Authors: Bohrmann, Gerhard, Kuhn, Gerhard, Abelmann, Andrea, Gersonde, Rainer, Fütterer, Dieter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 1990
• Subjects: Indian; Southern Ocean
• Online Access: https://oceanrep.geomar.de/id/eprint/31342/; https://oceanrep.geomar.de/id/eprint/31342/1/1-s2.0-002532279090034H-main.pdf; https://doi.org/10.1016/0025-3227(90)90034-H

A porcellanite layer, probably younger than 0.6-0.4 Ma, of a nearly monomineralic composition of opal-CT was sampled on the Southwest Indian Ridge during Polarstern cruise ANT-VI/3. The intense cementation of the rock, together with recent findings by the Ocean Drilling Program (Legs 113 and 120) and the occurrence of a unique older porcellanite from Eltanin Core 47-15, provides evidence of very early silica precipitation in pure diatom oozes of the Southern Ocean. Such porcellanites occur in shallowly buried young sediments and provide a contrast to the established concepts of porcellanite formation.