USAP-DC

Understanding the origins and nature of heat available at the base of the cryosphere is essential in deciphering the extent and residence time of the ice in Antarctica and its oceans. Constraints on parameters that control ice-sheet stability, response of the crust to ice loading and unloading, and the effects of volcanism and heat from Earth’s interior on overlying ice is of broad interest to the global climate change community. The goal of this study is to identify and to document the distribution of heat source and heat flux within the seafloor of the southwestern Ross Sea. Geothermal heat flux is one of the basic parameters that shape and control ice flow, ocean circulation, and ecosystem, connecting with subglacial hydrology and its influence on the ability of the ice sheet to slide and internally deform. Despite the importance, particularly in the Antarctic environments, there have been few investigations made in the Ross Sea on how lithospheric heat flux contributes to cryospheric dynamics over time. The project study site in the western Ross Sea seafloor comprises the Terror Rift, which represents the youngest phase of extension within the West Antarctic Rift System, one of the world’s largest rifts and the only one covered by continental ice sheets. The thinned western Ross Sea lithosphere and Terror Rift encompasses active volcanism that range from 5 million years to present-day, suggesting that Pliocene-Quaternary fault movement and dynamic changes in ice sheet extent and thickness over this period are concurrent with magmatic activities. This project will conduct a shipboard survey of the western Ross Sea seafloor. The datasets to be collected include seafloor heatflow/conductivity measurements, real-time seafloor visualization, water-column hydrothermal signal acquisition, and rock sampling via dredging. Heat flow and direct seafloor observations will provide an unprecedented context for seafloor-ocean interactions, addressing some of the biogeochemical cycles in the water column (e.g., chemical and nutrients contributions to the water column from seafloor volcanism and resultant hydrothermal systems) in constraining Ross Sea ecosystems. The compilation of all the data will enable the testing of hypotheses that magmatic intrusion and volcanism in the western Ross Sea is the primary lithospheric heat source that has influenced the dynamics of the ocean-cryosphere system in this region. Data collected will also allow us to refine current timeseries and geodynamics that drive one of the world’s major continental rift systems. Deliverables from this project will be new geospatial information data, including all the underway geophysics grids of the area, publicly available via NSF funded data repositories. After acquiring geochemistry and geochronology, the remaining rock samples will be archived at the Polar Rock Repository. The project will also train 1 postdoc, 2 graduate students, and at least 3 undergraduate students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Person	Role
Tominaga, Masako	Investigator and contact

Antarctic Earth Sciences

Award # 2217127

USAP-2217127_1

Deployment	Type
NBP25-01	ship expedition

None in the Database

Repository	Title (link)	Format(s)	Status
R2R		Not Provided	exists