Geochemistry of the Sarvak Formation in the Kuh-e-Siah, Southern Iran

摘要

During Middle Cretaceous (Late Albian-Early Turonian) times, the Sarvak Formation carbonates prevailed in the coastal Fars area (Zagros), southern Iran. This study uses thin section descriptions and geochemical analysis to determine the depositional environment and diagenesis of the Sarvak carbonates. Geochemical studies of sedimentary rocks have raised many questions concerning the ability to separate primary from diagenetic signals. Since only a few elements associated with specific mineral phases are likely to be stable during burial, even to relatively modest depths, the recognition of primary compositional signatures has proved to be problematic. Nevertheless, the determination of major and trace elements can provide unique information which has been used successfully to determine original carbonate mineralogy and tracing diagenesis environments. Based on major and minor elements (Ca, Mg, Mn, Fe, Na, Sr) and petrographic studies indicate that aragonite was original carbonate mineralogy. Chemical studies illustrate that these carbonates were affected by meteoric diagenesis in a semi closed system. Originally aragonite limestones are abundant in ancient sequences and their formation and diagenesis can be better understood by using the geochemical data provided by this study.