The aim of this research is to investigate the diagenetic processes, paragenetic sequences, and the dolomitization model of the Taleh-Zang Formation (Late Thanetian) in the Lorestan Sedimentary Basin, utilizing petrographic and elemental geochemical evidence. For this purpose, three surface sections were selected and sampled. The lower and upper boundaries of the Taleh-Zang Formation in all four studied sections are conformable with the Amiran flysch Formation and the Kashkan clastic Formation, respectively. Petrographic studies led to the identification of several diagenetic processes, including micritization, cementation, neomorphism, compaction, dissolution, porosity, and replacement, which ultimately determined its diagenetic model. Based on petrographic evidence, the paragenetic sequence of the Taleh-Zang Formation deposits in these sections is interpreted across four environments: marine, burial, uplift, and fresh water. These processes have passed through three diagenetic stages: early (eogenesis), middle (mesogenesis), and late (telogenesis). Dolomites in the studied sections formed as both primary and secondary. Elemental analysis of the samples by EDS method (with an accuracy of one-hundredth percent) on the dolomites showed that primary dolomites possess low Fe content and high amounts of Sr and Na, whereas secondary dolomites have a high concentration of Fe and Mn and lower Sr content compared to primary dolomites. This finding suggests a shallow to deep diagenetic burial environment for the secondary dolomites. The dolomitization model of the Taleh-Zang Formation deposits in all three studied sections is attributed to tidal flat, seepage, shallow burial, and deep burial settings.