Review of Japanese Taiga project 3:
Geodynamics of the Southern Mariana Trough Back-Arc Basin
Nobukazu Seama
Department of Planetology, Kobe University
The Southern Mariana Trough back-arc basin is acurrently active backarc basin, and it has fast spreading morphologic and geophysical characteristics, suggesting an additional magma supply, even though the full spreading rate is categorized as slow spreading. Five hydrothermal vent sites have been found within 5km around the spreading axis at 13oN. The Japanese TAIGA Project selected this area as one of three integrated target sites. I reviewed the results from these geophysical surveys in this integrated target site during the TAIGA Project. The results are summarized in two important points: 1) the mantle dynamics and the crustal formation at the Southern Mariana Trough back-arc basin are influenced by hydration derived from the subducting slab with accompanying the additional magma supply, and 2) characteristic features on the hydrothermal activity of the Southern Mariana Trough back-arc basin are different between on-axis and off-axis hydrothermal sites.
