Overriding Plate Thickness as a Controlling Factor for Trench Retreat Rates in Narrow Subduction Zones
Metadatos
Mostrar el registro completo del ítemEditorial
Wiley
Fecha
2024-02-09Referencia bibliográfica
Gea, P. J., Mancilla, F. D. L., Negredo, A. M., & van Hunen, J. (2024). Overriding plate thickness as a controlling factor for trench retreat rates in narrow subduction zones. Geochemistry, Geophysics, Geosystems, 25, e2023GC011345. [https://doi.org/10.1029/2023GC011345]
Patrocinador
Grant PID2019.109608GB.I00 funded by MCIN/AEI/ 10.13039/501100011033; Spanish Government projects PID 2020‐114854GB‐C22 and PID2022‐ 139943NB‐100; National Science Foundation under award EAR‐0949446 and EAR‐ 1550901; Redes de Comunicación (CSIRC), Universidad de Granada; Hamilton HPC cluster, University of DurhamResumen
Slab width is a significant factor in controlling subduction zone dynamics, particularly the retreat velocities, which tend to decrease with wider slabs. However, observations of natural narrow subduction zones reveal no correlation between slab width and trench velocities. This suggests that other factors may exert a greater influence. In this study, we employ 3D numerical subduction models to systematically assess the impact of slab width, strength of slab coupling to the lateral plate (LP), and overriding plate (OP) thickness on trench kinematics and geometry. Our models focus on narrow slabs (400–1,200 km), and the results demonstrate that, in the case of narrow subduction zones, the slab width has little effect on trench migration rates and the viscous coupling at the lateral slab edge is only important for very narrow subduction zones (≤800 km). Conversely, the OP thickness emerges as a crucial factor, with increasing plate thickness leading to a strong decrease in trench velocities. These findings provide an explanation for the observed trench velocities in natural narrow subduction zones, where an inverse relationship with OP thickness is evident. Furthermore, our study reveals that not only slab width, but also the OP thickness and the slab coupling to the LP, significantly influence trench geometry. Strong lateral coupling promotes the formation of concave trench geometries, while thick overriding plates favor the development of “w”-shaped geometries. Overall, a comprehensive understanding of subduction processes necessitates considering the interplay between slab width, OP thickness, and slab coupling to the LP.