Northeastern (46th Annual) and North-Central (45th Annual) Joint Meeting (20–22 March 2011)

Paper No. 5
Presentation Time: 3:00 PM


GOERGEN, Eric, Geological Sciences, Brown University, Geochemistry Building Room 030, Providence, RI 02912 and HIRTH, Greg, Geological Sciences, Brown University, Box 1846, 324 Brook St, Providence, RI 02912,

This project is focused on exploring the kinetic driving forces and mechanistic interactions fundamental to the development of reaction-induced strain localization in rocks. While strain localization occurring as a result of simultaneous reaction and deformation has long been acknowledged, there is still a lack of understanding related to the initiation of reaction and the subsequent time-dependent microstructural and reaction dynamic evolution of strain localization. We investigate these processes through a series of deformation experiments carried out on rocks of lherzolite bulk composition. These experiments were designed to explore strain localization through three approaches: 1) investigating the known positive correlation between reaction rate and strain rate; 2) characterizing the time dependent evolution of microstructures associated with reaction-induced strain localization through a series of experiments carried out to increasing amounts of finite strain; and 3) investigating the effect of bulk composition on the progress of reaction and localization by varying modal amounts of phases present in starting materials. Analysis of experiments is focused on microstructures developed via chemical and crystallographic analysis to develop models of the kinetic and mechanic history within and between experiments. In addition, the choice of the lherzolite chemical system and pressure-temperatures for these experiments provides fundamental rheologic data on the upper mantle in the context of evolving bulk composition and phase assemblages.