Active undersea volcanism near Fiji

The western Pacific basin is pockmarked with active and extinct volcanoes related to the subduction of the Pacific plate along almost all of its western boundary. An Australian National University research group recently discovered a pair of undersea volcanoes that would put any good mining geologist into a fit of joy. These volcanoes are spewing volcanic gases underwater that are very rich in metals like copper, lead, zinc and gold. All of these metals like to go into solution in acidic fluids like volcanic gases, and when these volcanic fluids meet the cold (and decidedly less acidic) seawater, they precipitate the metals (amongst other things). We have seen this before at mid-ocean ridges at black smokers.

These undersea volcanoes are by no means unique, but they are rather large (50-km wide, 4000-m tall) and active. Just looking at their morphology (see image above), they look like large shield volcanoes, such as Kilauea or any of the volcanoes (like Cerro Azul) in the Galapagos – just not at the surface yet. The researchers point out that they could be seen as modern analogs to some of the large volcanogenic mineral deposits that are rich in gold and copper (and other metals).

The volcanoes have been dubbed Dugong and, well, Lobster. I can’t wait until the next big eruption of Mt. Lobster!