Timing and Formation of the Manihiki and Hikurangi Plateaus and Their Influence on Ocean Conditions

Large igneous provinces are features in which massive volumes of magma are emplaced over a short period of time. Ontong Java Nui is a massive large igneous province in the Pacific basin that formed ~119 million years ago and may have been the driver of a global anoxia event in the ocean basins. This project will conduct high-resolution age experiments on lavas from Ontong Java Nui. The results will confirm whether the eruptions happened at the same time as the global anoxia event and thus may have been its cause. The results will clarify how large volcanic events can alter ocean chemistry and environmental conditions that influence marine ecosystems and the distribution of oxygen in the oceans. The project will also provide training for early-career scientists, strengthen analytical capabilities, and engage broader audiences through research and outreach activities. Ocean anoxia event 1a is marked by the deposition of organic-rich marine sediments globally over a short (1.1 million years) duration. The primary hypothesized causal mechanism for the event is the emplacement of massive Ontong Java Nui LIP, which is composed of the Ontong Java, Manihiki, and Hikurangi Plateaus. Recent high-resolution ages of the Ontong Java Plateau indicate an emplacement prior to the anoxia event. This project will conduct 40Ar/39Ar high-resolution age determination experiments on samples from the Manihiki and Hikurangi Plateaus. The results will address three primary questions: 1) What was the timing, duration, and potential pulses of the Manihiki and Hikurangi Plateau emplacement? 2) Is the potential shallow or subaerial outgassing of the Manihiki Plateau contemporaneous with ocean anoxia event 1a? 3) What are the rates of crustal growth associated with the two episodes of plume-triple junction interaction that coincided with the breakup of Ontong Java-Nui? The results will have implications for how marine LIP emplacement affect ocean conditions. 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. NSF Award ID: 2535264 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Kevin Konrad | Institution: Oregon State University, CORVALLIS, OR | Award Amount: $499,008 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2535264 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2535264.html