Collaborative Research: Was early Cenozoic Samoa and Rarotonga volcanism suppressed when the Ontong Java Plateau drifted over the hotspots?

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Volcanic hotspots beneath the ocean have created chains of underwater volcanoes and islands over millions of years. This project will study seamounts near the Ontong Java Plateau, the largest volcanic structure on Earth, to improve understanding of how heat and material move from deep within the Earth to the surface and shape our planet over time. Early-career scientists, graduate students, and undergraduate students will take part in the cruise. In port, the science team will lead ship tours for local public schools and media. While at sea the proponents will make a training video that outlines how to prepare for and carry out a successful cruise. Recent work offers hints that the currently active Samoan hotspot may be a long-lived mantle melting anomaly, or hotspot, that has been active since the Cretaceous. Many of the 87 to 106 million year old volcanoes in the Magellan Seamount Chain, located north of the Ontong Java Plateau, have Samoan hotspot geochemical signatures. In addition, their ages and locations match predictions for the Samoan hotspot made using absolute plate motion reconstructions. Reconstructions of the Samoan hotspot show that the plateau passed over the Samoan plume ~60-30 million years ago, and over the Rarotonga plume—a second, possibly-long-lived hotspot—~60-50 million years ago. This project will conduct a marine field program to sample the seamounts along the modeled traces of these two hotspot tracks to test 1) whether the Ontong Java Plateau passed over the Samoan and Rarotonga plumes and 2) whether the passage of thick lithosphere results in lower degree melts with stronger enriched mantle signatures. A combination of geochemical and geochronology analyses will uniquely identify contributions from these two hotspots. 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.