This project investigates the diagenesis of a partially dolomitized sequence of Upper Miocene reefal limestones cropping out on the island of Mallorca, Spain. Unusually good exposures of these ancient reefs has allowed Dr. Luis Pomar (Univ. of the Balearic Islands) to define a detailed sedimentological and stratigraphic framework and to relate periods of reef growth and erosion to changes in relative sea level. This previous work is an ideal framework for our proposed detailed study of post- depositional changes (diagenetic alterations) that took place when the reefs and carbonate sediments were transformed to limestone and dolomite. In collaboration with L. Pomar we have begun field work, and have begun petrography and geochemistry at Stony Brook. The fundamental goal of our project is to quantitatively decipher the dolomitization processes and their rates. Our approach is to combine detailed field work with laboratory studies: petrography (plane-light, luminescence, scanning electron microscopy), transmission electron microscopy, fluid inclusion work, geochemical studies (O, C, Sr, B isotopes; Ca, Mg, Sr, Mn, Fe, Na abundances) of dolomites and associated diagenetic calcites. Quantitative modeling of geochemical data and of potential dolomitizing fluids will be used within the geologic constraints to develop a model(s) for the diagenetic processes acting on the reef complex.
