Elemental and isotopic oscillations in subduction zone minerals: implications for tectono-metamorphic processes and mass transfer?

Petrology Lunch with Dr Freya George 

https://www.freyageorge-geology.com/

Abstract

The compositional zoning exhibited by many metamorphic minerals serves as a time-resolved record of processes occurring during mineral growth and diffusive relaxation. In garnet derived from a global suite of subduction zones, oscillatory elemental zoning—rhythmic cycles of peaks and troughs in concentration—is near ubiquitous. This zoning may therefore reflect a fundamental dynamic or petrogenetic process operating during garnet crystallization in the subducting slab. In this talk, I will present data that investigates the potential for fluid buffering of elemental zoning and discuss the record of high-pressure fluid and mass transfer preserved in garnet. Our findings suggest multiple mechanisms of chemical/mass transfer operate at the grain and rock scale during subduction, but are unable to account for the elemental oscillations, which may instead form in response to externally triggered changes in solubility or fluid pressure.

Jion us in person or via Zoom https://bristol-ac-uk.zoom.us/j/91476700603?pwd=MDJXNVVxU0RsUUlPdkloR3VFWDJIQT09