Submarine lava fields in French Polynesia

• Discovery of submarine flood lavas near Marquesas Fracture Zone
• Discovery of volcanic clusters on the eastern tip of the Pukapuka Ridges, and southeastern off MacDonald Seamount
• A volcanic cluster made up of both old and young volcanic cones.
• Tiny and young volcanoes to be similar to petit-spot volcanoes rather than zero-aged hotspots

Shipboard multibeam survey is powerful tool to locate submarine volcanoes especially having small volume. Small submarine volcanoes may represent the initial stages of hotspot activity, but they may also form via lithospheric flexing, regional convection of the mantle, and the presence of fracture zones. Here we describe several volcanoes, flood lavas, and volcanic clusters in French Polynesia using data from archives of multibeam data. The clusters of small volcanoes are similar to petit-spots, and they are not considered to represent the initial stages of a hotspot as they are composed of both young and old edifices, and because the sites are located far from any known hotspot. These newly discovered submarine volcanoes are located in areas with low-velocity seismic shear waves at depths of 60 and 100 km. These lava fields will therefore facilitate geochemical mapping of the mantle in areas unrelated to hotspots, because these lavas may have developed from melts in the shallow mantle beneath French Polynesia.