Mineral carbonation in the Abyss
During the recent meeting of the EU FP7 Initial Training Network “Abyss” in Sestri di Levante, on the Ligurian Coast to the east of Genoa, Professor Damon Teagle , PhD student Barbara Zihlmann, and post-doctoral research fellow Dr Aurélien Beaumais from Ocean & Earth Science at Southampton were taken to visit the wonderful outcrops of the famous Rocco Rosso di Levanto (Fig.1), by Professors Elisabetta Rampone and Laura Crispini of the University of Genoa and Riccardo Tribuzio from the University of Pavia.
Researchers in the Abyss network investigate a variety of reactive fluid-rock geological systems from the mantle to the abyssal sub-seafloor. Hence it was appropriate to see some of the most picturesque examples of mantle ophicalcites exposed in active quarries near the village of Reggimonti. These ophicalcites are ancient rocks that record reactions on the Jurassic seafloor where the magnesium-rich “peridotite” rocks of the upper mantle become uplifted at slow spreading mid-ocean ridges, and interact with seawater to form highly reducing, high pH (>11) fluids that precipitate large amounts of calcium carbonate. Similar reactions occur today at the Lost City hydrothermal system on the Mid-Atlantic Ridge. These are natural examples of “mineral carbonation” that has been suggested as a potential approach to capture and safely store anthropogenic CO2 as benign carbonate minerals. Ancient slices of ocean crust and upper mantle, known as ophiolites, are relatively common in mountains around the world with the best known examples being the Troodos massif of Cyprus and the Semail ophiolite of Oman. If the natural mineral carbonation processes could be enhanced to the industrial scale, they could potentially provide mechanisms to capture and store climatically significant quantities of carbon dioxide.