2:45 PM - 3:00 PM
[U20-03] Direct sampling and measurement at deep crust through scientific ocean drilling
Keywords:Ocean Drilling, Chikyu, Mantle Drilling, Borehole Monitoring, Borehole Experiment
The scientific ocean drilling vessel Chikyu has been started scientific ocean drilling operation since 2005 and reached about 3.3km below the seafloor in 2019. It is the current world record of the deepest borehole as scientific ocean drilling conducted at the Nankai accretionary wedge. Achieving mantle drilling by “Chikyu” that has never reached humanity is her next challenge. In addition, a mantle observation and experiment system using boreholes will be planned. The Mantle drilling will provide a fundamental understanding of the Earth system, such as the compositional distribution from the oceanic crust to the upper mantle, rheology, life and chemical evolution processes, and the behavior of thermal and environmental variables. Deepwater and deep penetration technology are under development. We are discussing the first target of Mantle drill at off Hawaii where relatively low temperature and reachable depth to the upper-most mantle by ocean drilling. Scientific drilling cut core samples and measure and/or monitor physical/chemical properties in the borehole. That is the only way to do material science and in-situ high-resolution measurements and monitoring, and it is the uniqueness of ocean drilling.
Chikyu has been completed relatively shallow depth drilling campaigns to understand the mechanism of large earthquakes and Tsunamis, the deep life under extreme conditions and the marine mineral resources so far. The scientific results will be presented in addition to future technology developments for the deep drilling into our planet.