Subduction Initiation at the Solomon Back‐Arc Basin: Contributions From Both Island Arc Rheological Strength and Oceanic Plateau Collision
Liangliang Wang, Liming Dai, Wei Gong, Sanzhong Li, Xiaodian Jiang, G. R. Foulger, Hao Dong, Zhong‐Hai Li, Shengyao Yu
Abstract
Abstract It is generally accepted that the subduction polarity reversal (SPR) results from the strong collision of two plates. Yet, the SPR of the Solomon Back‐arc Basin is started in the “soft docking” stage, and the mechanism by which the “soft docking” induced subduction initiation (SI) remains elusive. We find that the mass depletion of the plateau influences the evolution of the subduction patterns during SI. And the island arc rheological strength affects the development of the shear zone between an island arc and back‐arc basin which favors SI. What's more, with the increase of the rheological strength difference, the SI is more easily to occur, and the contribution of the plateau collision to SI weakens. Hence, by combining the available geological evidence, we suggest that the Solomon Island Arc rheological strength and the Ontong‐Java plateau collision jointly controlled the SI during the “soft docking” stage.