Evaluating the redox evolution of fluids in water-rich asteroids

CM-group carbonaceous chondrite meteorites are currently the best match for delivering water and organic materials to the terrestrial planets. However, they have been severely affected by the action of water driven reactions on their parent body which may have modified their water and organic content. Therefore, it is of fundamental importance to understand how these water-rich meteorites were affected by aqueous alteration on their parent asteroid and how that fluid evolved over time. We propose to use Synchrotron Mössbauer source to measure Fe2+ and Fe3+ charge state ratios and determine the redox conditions that formed a suite of minerals produced by progressive aqueous alteration within the Winchcombe CM meteorite. From this result we will be able to evaluate how many fluids affected these asteroids and how those fluids evolved over time.