CAREER: Probing the connections between mantle convection and oceanic gateways in the North Atlantic using deep-sea drilling

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

Hot mantle material rises up beneath Iceland from deep within Earth’s interior forming a giant plume that pulses on timescales of millions of years. Plume pulsing contributes to changes in the height of oceanic gateways that link Greenland, Iceland, and Scotland. These gateways control the amount of cold, deep water that has flowed from the Norwegian Sea to the Atlantic ocean over the past few million years. This project will examine the history of plume activity and ocean circulation in the North Atlantic region using data from rock cores collected deep beneath the seabed. The outcomes of this project will have immediate impact upon our knowledge of past ocean circulation and climate, which is key to addressing the environmental challenges that society is confronting today. Broader impacts include participation in workshops for local teachers, delivery of K-12 activities, development of a first year Earth systems class, and support for a post-doctoral scholar and graduate students. The flanks of Reykjanes Ridge south of Iceland lie above one of Earth’s largest plume-ridge systems, and are covered by rapidly accumulating contourite drift sediments that are sensitive to the oceanographic conditions influenced by adjacent deep-water gateways. This configuration provides an ideal natural laboratory to test hypotheses about the interactions between mantle dynamics, paleoceanography, and climate. This project will investigate the extent to which the Iceland mantle plume has controlled oceanic gateways and deep-water circulation in the North Atlantic Ocean during Cenozoic times. Samples and data collected at sites on Björn and Gardar contourite drifts during International Ocean Discovery Program Expedition 395 provide an opportunity to significantly advance our understanding of the history of sedimentation patterns and ocean circulation across the North Atlantic region. Kinematic and paleobathymetric models for ocean basin evolution will be integrated with sediment accumulation rate and current speed estimates from recently drilled cores, as tools to decipher past ocean circulation patterns. Considered together, the proposed models and observations will provide insights into the coupled nature of Earth’s interior, ocean, and surface domains. 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.