Tectonic & Petrologic Evolution of the Atlantis Bank Oceanic Core Complex
The interplay between rifting, magmatism, and circulation of seawater within the crust is complex in the zone where oceanic plates form. This study aims to map the distribution of each of these components of the system at an advantageous site in the Indian Ocean- the Atlantis Bank. Long-lived faulting and uplift has exposed a cross section of the plate and data from several past research cruises are available but had not previously been systematically analyzed and compiled. Curation and ingest of the data into the Integrated Earth Data Applications database will make the results openly available, and an undergraduate intern will receive training in this work. The completed geologic map and interpretations will serve as Site characterization for new, deep International Ocean Discovery Program scientific drilling that is scheduled to begin in 2016, as well as incorporating results of prior drilling. A new geologic map of Atlantis Bank will be made and used to address questions about the 3-D structure and development of the Atlantis Bank oceanic core complex. Analysis of existing dive and dredge samples will build on recent recognition of the importance of strain localization and ways that magma and hydrothermal fluids may play a role in its evolution. Relations between dike and gabbro injection will be systematically explored, taking advantage of the few Myr window of time accessible in the Atlantis Bank seafloor exposures. In addition to new mapping based on existing sample and seafloor video, the project will combine prior results in a more comprehensive 3-D geologic interpretation. The dike/gabbro analysis is envisioned as a test of the lithospheric 'rollover' model of ocean crust formation.