241-11 Volcanism in a Tectonic Crossroads: Isotopic Clues to Plume Versus Ridge Contributions at Socorro Island, Mexico

Session: Petrology, Volcanology, and Mantle Plumes across the Solar System, Part I

Presenting Author:

Mauro Mingo

Authors:

Mingo, Mauro Andres¹, Widom, Elisabeth², Kuentz, David C.³, Siebe, Claus⁴, Salinas, Sergio⁵, Lippitt, Rebecca⁶, Kelley, Katherine A.⁷, Pockalny, Rob⁸, Carey, Steven⁹

(1) Miami University, Geology & Environmental Earth Science, Oxford, OH, USA, (2) Miami University, Geology & Environmental Earth Science, Oxford, OH, USA, (3) Miami University, Geology & Environmental Earth Science, Oxford, OH, USA, (4) Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México, Mexico, (5) Universidad Nacional Autónoma de México, Ciudad de Mexico, Ciudad de Mexico, Mexico, (6) University of Rhode Island, Graduate Sch. of Oceanography, Narragansett, RI, USA, (7) University of Rhode Island, Graduate Sch. of Oceanography, Narragansett, RI, USA, (8) University of Rhode Island, Graduate Sch. of Oceanography, Narragansett, RI, USA, (9) University of Rhode Island, Graduate Sch. of Oceanography, Narragansett, RI, USA,

Abstract:

Socorro Island, part of the Revillagigedo Archipelago and a UNESCO World Heritage Site, is a volcanic shield edifice that has been active for at least several hundred thousand years. Its eruptive history includes episodic caldera-forming events and sustained subaerial volcanism. A particularly intriguing aspect of Socorro’s magmatic evolution is its location in the now-extinct Mathematician Ridge, an aborted oceanic spreading center that ceased spreading 3.5 million years ago. Despite ridge extinction, magmatic activity on Socorro has persisted, with the most recent eruption occurring at a submarine vent in 1993. The processes sustaining this post-rift volcanism remain poorly understood, prompting further investigation into the island’s mantle sources and their evolution through time.

This study seeks to characterize the origin and temporal evolution of magmatism throughout Socorro Island’s volcanic history from the early shield-building phase to more evolved subaerial eruptive stages. We conducted extensive field sampling across the island, collecting volcanic rocks that span a bimodal compositional range from primitive basalts to highly evolved rhyolites. In addition, cruise RR2403 enabled recovery of submarine samples from the island’s flanks, representing older phases of Socorro construction, the Mathematician Ridge axis, and adjacent seamounts such as Clariaut, located east of the ridge and possibly linked to its former spreading phase. Radiogenic isotope analyses (Sr-Nd-Pb-Hf) were employed to probe mantle source characteristics and tectono-magmatic connections.

Isotopic data reveal that Socorro lavas are compositionally distinct from both the Mathematician Ridge and Clariaut Seamount, suggesting different mantle source characteristics. However, some ridge samples exhibit intermediate isotopic compositions and trajectories converging with those of Socorro lavas, implying a potential spatial or temporal link in mantle domains. This overlap may signal transitional melting regimes or mantle flow reorganization following ridge extinction. Our findings underscore the complexity and longevity of magmatic systems in aborted rift settings and offer new perspectives on how mantle dynamics can sustain volcanism long after spreading has ceased.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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