This project will utilize two scheduled JAMSTEC cruises, to study the forearc SE of Guam and submarine volcanoes NW of Guam. The main objective of the first cruise is to build upon previous studies of the structure, composition, age, and mode of formation of the exposed Mariana forearc crust and upper mantle. Earlier studies provided information about the lower crust and upper mantle as well as samples of the arc and forearc crust. These data indicate that the crust may be only 3 km thick beneath the outer forearc, and therefore accessible for drilling complete crustal sections. On this cruise, the PIs and students will sample remaining pieces of the arc crust in the region, to gain a better understanding of the geometric and geologic relationships between rock types that make up the Mariana forearc crust and upper mantle. The cruise will involve 6 US scientists and 2 graduate students who aim to identify candidate sites for future ALVIN dives and IODP drilling in the southern IBM forearc.
The main objective of the second cruise is to examine three submarine volcanoes in the Southern Mariana Arc, including NW-Rota-1, which is an active submarine eruption. Additionally, the PIs will study and sample hydrothermal alteration and stockwork sulfide mineralization exposed in the caldera wall of one of the three volcanoes, and perform an exploratory dive to the largely unexamined Tracey Seamount west of Guam.
Broader Impacts This project represents a collaborative effort among nine US universities and two federal agencies as well as an international collaboration between scientists from the US and Japan. The project will also help support and train three Geoscience graduate students, each from different academic institutions. Results from the two cruises will be used to determine future Ocean Drilling projects.
