Exploring the archive data of low grade - high pressure metamorphic sedimentary successions

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Despite blueschist facies high pressure (HP) metamorphism, metasedimentary rocks of the Anatolide-Tauride belt in western Anatolia exhibit widely distributed primary sedimentary texture. The rock types relevant for this proposal comprise previously undescribed evaporitic sequences in Lower Cretaceous pelagic successions of the Neotethys. The rocks are exposed over large areas and correlate in time to Aptian evaporites in the Atlantic ocean. Preliminary work showed that volumetrically important abundances of primary selenite crystals (up to 1.5 m crystal length) were transformed to aragonite during early diagenesis. Subduction-related deep burial was followed by exhumation, which led to the transformation from aragonite to calcite. Along with these processes, macro- and microscopic primary textures and structures remained unaltered. Petrographic investigations revealed exceptionally well-preserved primary textures in selected domains of these rocks. We propose to investigatephenomena of multiple pseudomorphism using mineralogical tools (EMPA, Raman spectrometry, cathodoluminescence), geochemistry (LA-ICP-MS) and isotope geochemistry of delta18O, delta13C, delta26Mg and 87Sr/86Sr isotopes. The aim of these investigations is to enhance the understanding of early diagenetic processes and metamorphic reactions as well as to quantify element fluxes. The research proposed here will potentially lead to a significantly increased understanding of geochemical fluxes and thermodynamic processes in low grade HP metasedimentary rocks leading to an improved understanding of these archive rocks.