SS07-2008

Structure, evolution, petrology, and hydrothermal activity of spreading centres in the northern Lau Backarc Basin The InterRidge Office would like to highlight an Australian research cruise currently underway in the northern Lau Back-arc Basin (NLB). The SS07-2008 cruise, led by Chief Scientist Richard Arculus from Australian National University, will be in two legs from 30 April - 7 June 2008 on R/V Southern Surveyor. The objective of the first leg will be to survey the bathymetry, magnetic characteristics, petrology, hydrothermal activity, and hence origins and evolution of two of four spreading centers within this region (Northwest Lau [NWLSC] and Niuafo’ou [NSC]), which are essentially unstudied. This first leg will build on the efforts from the NoToVE cruise in 2004 in which the other two spreading centers within this region (Fonualei Rifts and Futuna) were surveyed. The objective of the second leg is to extend the area of exploration to the Peggy Ridge, a leaky transform linking spreading centers in the southeastern Lau Basin with the NWLSC and Futuna SC to the north of Fiji. Questions to be addressed include: 1. How does the plate tectonics of the rapidly extending NLB work? 2. What are the nature and source characteristics of the magmatism accompanying the different crustal accretion variables in the NLB? 3. Does the Samoan mantle plume penetrate beneath the NLB? 4. What are the characteristics of volatile distribution in the mantle sources of NLB basalts? 5. What are the hydrothermal characteristics of the NLB? Participants from several Australian universities, government agencies, and industry are involved. The cruise also involves collaboration with scientists from the USA, including Katherine Kelley (University of Rhode Island), Ron Greene (NOAA), and graduate student Michael Chandler (University of Hawaii). **UPDATE July 2008*** Press release: "Undersea volcanoes, hot springs found off Fiji coast" http://news.webindia123.com/news/Articles/Science/20080620/979311.html Press release: "Active Submarine Volcanoes Found Near Fiji" http://www.sciencedaily.com/releases/2008/06/080619093259.htm ***