Geochronology of the Wrangell Arc: Spatial-temporal evolution of slab-edge magmatism along a flat-slab, subduction-transform transition, Alaska-Yukon

A new geochronological study reveals the spatial-temporal evolution of magmatism in the Wrangell Arc, a region characterized by some of Earth's largest Quaternary volcanoes. The research documents the initiation of magmatic activity around 30–17 million years ago along the Totschunda fault and its subsequent southeastward progression at 17–10 million years ago along the Duke River fault, attributed to dextral strike-slip faults and changes in slab geometry. Later phases (13–6 Ma) show westward progression, while recent magmatism (6 Ma to present) has moved northwestward, correlating with increased plate convergence rates. The study attributes voluminous magmatism to shallow subduction-related flux melting and slab edge melting driven by asthenospheric upwelling along the Yakutat flat slab's lateral edge. Additionally, rivers sampled yielded Paleozoic–Mesozoic detrital zircon and volcanic lithic age populations, reflecting earlier magmatic episodes in underlying accreted terranes.

Trop, J. M., Benowitz, J. A., Kirby, C. S., & Brueseke, M. E. (2021). Geochronology of the Wrangell Arc: Spatial-temporal evolution of slab-edge magmatism along a flat-slab, subduction-transform transition, Alaska-Yukon. Geosphere, 18(1), 19–48. https://doi.org/10.1130/ges02417.1