A LOOK INTO THE GEOLOGY OF THE SOUTHERNMOST MARIANA TRENCH THROUGH XRF ANALYSES OF OCEAN FLOOR ROCKS

The southernmost area of the Mariana Trench at 11-12 degrees north and from 139-144 degrees east is a large, complex and challenging area to study. On a typical geological map this southern area of the Mariana Trench would show as part of the arc system basin and or trough, however though not as prominent as the main Mariana arc to the northeast there is still a fore-arc bulge marked by ridges and sea mounts where the region is still uplifted from the underthrusting Philippine plate. Retrieved from the Jamstec research cruises YK15-11 and YK16-14 this presentation looks into the geochemistry of more than thirty rock samples collected along the fore-arc side from depths of 1700 meters among the ridges to 5800 meters along the trench slope from the 139-144 degrees east section. These samples are analyzed by Thermo Fisher Scientific’s Niton Xl3t Ultra handheld XRF and checked for accuracy per USGS standards and professional XRF analyses to display major oxides and important trace elements. Initial findings show a range of compositions including basalts, andesites, and some volcanoclastics. Though research into the geology of the southern Mariana fore-arc is not groundbreaking this study hopes to provide more information and understanding in one of the most interesting and dynamic areas of the Izu-Bonin-Mariana Arc.