305-9 Petrographic and Microstructural Investigation of the Queyras Gabbros: Assessing the Influence of Fe-Ti Oxides on Pyroxene and Plagioclase Deformation

Session: Subduction Zone Processes: Insights from Geology, Geochemistry, and Petrochronology (Posters)

Presenting Author:

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Abstract:

Gabbroic rocks are the most abundant rock in the oceanic and lower continental crusts, both of which play a crucial role in many geodynamic processes such as plate tectonics, mid-ocean ridge formation, and the subduction cycle. Yet, their rheology remains poorly understood. In this study, we aim to constrain the mechanical evolution and strain localization processes of grabbro at the brittle-ductile transition. We focus our analysis on three sites located in the Queyras Massif (French Alps) that represent well-preserved fragments of the Tethyan oceanic lithosphere interpreted to have formed along a slow-spreading ridge. The origin of these gabbros has been interpreted to be an oceanic core complex before subduction and exhumation during the alpine orogeny. We present the results of a detailed petrological and microstructural analysis of the pyroxene, plagioclase, and Fe-Ti oxides on our gabbros samples. Future findings from this research will improve current models of plate dynamics, mid-oceanic ridge and oceanic core complex formation, and subduction processes.

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

doi: 10.1130/abs/2025AM-6986

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