Pacific hotspots reveal a Louisville-Ontong Java Nui tectonic link

Area of Science:

• Geosciences
• Geochemistry
• Geochronology

Background:

• Volcanic hotspots form age-progressive tracks due to mantle plumes and plate motion.
• The Ontong Java Nui Plateau (OJP-Nui), a massive igneous province, lacks a clear volcanic track.
• Previous models struggle to link the Louisville hotspot to OJP-Nui due to limited early Pacific plate motion data.

Purpose of the Study:

• To identify and characterize long-lived Pacific hotspots.
• To refine Pacific absolute plate motion models.
• To resolve the origin of the Ontong Java Nui Plateau.

Main Methods:

• Geochemical analysis of volcanic rocks.
• Radiometric dating (geochronology) of Pacific seamounts.
• Paleomagnetic analysis to determine past plate positions.

Main Results:

• Samoa and Rurutu-Arago hotspots are identified as the longest-lived in the Pacific, dating back over 100 million years.
• These hotspot tracks provide new constraints on Pacific plate rotation between 80 and 100 million years ago.
• The Louisville volcanic track can now be linked to the OJP-Nui without invoking significant plume motion.

Conclusions:

• The study revises our understanding of Pacific plate tectonics and hotspot evolution.
• It provides a coherent model for the formation of the Ontong Java Nui Plateau.
• The findings highlight the importance of ancient, subducted hotspot tracks in reconstructing plate history.