Effects of fluids on the accretion and exhumation of young oceanic lithosphere at slower-spreading mid-ocean ridges

• Grant number: 24/17365-6
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: March 10, 2025
• End date: December 09, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Frederico Meira Faleiros
• Grantee: Rhander Taufner Altoe
• Supervisor: Ake Fagereng
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Cardiff University, Wales
• Associated to the scholarship: 23/13238-7 - Effects of fluids on the accretion and exhumation of young oceanic lithosphere at slower-spreading mid-ocean ridges, BP.PD

Abstract

Fluids have a profound effect on deformation of the Earth's crust, regardless their composition; yet where the fluids come from, how they are transported, and what physical and chemical processes dominate fluid-assisted deformation remains unclear. This is particularly the case for detachment fault zones that bound oceanic core complexes along (ultra)slow-spreading ridges, where fluid-rock interaction/reaction is argued to directly impact the composition and thermomechanical behaviour of the fault footwall, but for which data are limited. We willinvestigate the dominant deformation mechanisms that accompany fluid-reaction processes during crustal accretion in a magma-rich environment as a function of strain, depth and temperature in gabbroic rocks from the Atlantis Bank oceanic core complex (SW Indian Ridge). A combination of light, electron microscopy and electron backscatter diffraction techniques will be integrated using a unique combination of samples from Hole U1473A (IODP Expedition 360). We will constrain the consequences of fluid-rock exchanges that accompany deformation from hyper-solidus (i.e., melt-present) to ambient conditions. The results of this project will establish the role and impacts of fluid-lubricated deformation on the larger scale rheology in young ocean lithosphere in (ultra)slow-spreading environments near to ridge axes, especially in the highest temperature part of the system that has not previously been well understood or modelled with any existing flow laws.