image: Earthquakes and GPS velocity at Ulithi Atolls and Fais Atoll indicates the existence of a strike slip fault between these two atolls. Besides, the distribution of earthquakes makes known that this fault has cut through the lithosphere. Therefore, this fault is established as the plate boundary. view more
Credit: ©Science China Press
This study was led by Dr. Zhen Zhang (Fourth Institute of Oceanography, Ministry of Natural Resources) and Prof. Sanzhong Li (Key Lab of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences, Ocean University of China). Bathymetry data analysis conduced by Zhang reveals several special geological phenomena at Caroline Plate boundary. In the east, a series of seamount chains derived from the Caroline Hotspot have developed and are distributed in a regular arc pattern. In the west, spreading center and subduction zone are connected at Ayu Trough. At north, widely recognized plate boundary (Sorol Trough) did not seem to extend to the Yap Trench. “We may hold the key to evolution of Caroline Plate after its oceanic spreading,” Zhang says.
The team performed detail structural analysis at these regions. At north, the plate boundary was redefined as the strike slip fault between Ulithi Atolls and Fais Atolls (see image below). At east, these seamounts in a regular arc pattern resulted from convergence between the Caroline Plate and the Pacific Plate and crustal softening of the northeastern Caroline Plate induced by the Caroline Hotspot (see image below). Before that, a fulcrum was established here because the subduction at south would release the pressure. And then, softening of the crust caused by hotspot would led to dysfunction of this fulcrum. At west, a fulcrum was also established at the break point between spreading center and subduction zone. “These fulcrums are more like collision point between two knives,” Li says. After the reconstruction of Ayu Trough spreading history and Caroline Hotspot path, the team reconstructed the evolution of Caroline Plate with these two fulcrums.
“This work originates from basic bathymetry data, and submarine topographic data is quite common now. All the same, there are still many secrets to be discovered. We hope that this study will encourage scientists working on existing basic data in order to reveal more secrets,” Zhang says.
See the article:
Zhang Z, Li S, Wang G, Suo Y, Wang G, Wang P. 2022. Plate boundary processes of the Caroline Plate. Science China Earth Sciences, 65:1554–1567(2022). https://doi.org/10.1007/s11430-021-9919-6
Journal
Science China Earth Sciences