زاگون، پتروگرافی، دیاژنز، رخساره‌های سنگی، محیط رسوبی

Abstract

In this research Zagun Formation at the age of Early Cambrian in Sarbandan section with thickness of 192 meters, for determining petrography, diagenetic processes, lithofacies and depositional environment was analyzed. According to outdoor studies at that section, Zagun Formation is made of two lower units (Rock unit A) and upper (Rock unit B). This formation at lower parts (Rock unit A) is frequence fo shale and siltstone lithologies and at upper unit (Rock unit B) mainly lithologies of sandstone with interlayers of siltstone, shale and in some parts consists of conglomerate. The most important diagenetic processes affected the Zagun Formation are mechanical compaction, pressure solution, curvilinear and autogenetic micas, and veins filled by carbonate and silica cements. Analysis of lithofacies of Zagun Formation in Sarbandan section show presence of one fine-grained lithofacies (F1), Four medium-grained lithofacies (Sr, Sp, Sh, Sm) and one coarse-grained lithofacies (Gcm). Above facies and structural evidences as well as: mud cracks, planar cross bedding and herring-bone and wavy ripple led to identification of two facies collection, mud flat and mixed flat and tidal channel sedimentary subfacies .These collection of facies accociated with sedimentary structures has been Found and petrographical evidence, as well as presence of mineral of Glauconite, all shows that Zagun Formation have been deposited in the tidal flat environment, in a way that the lower unit (Rock unit A) in formation in Supra Tidal zone and upper unit (Rock unit B)of this formation in Inter Tidal zone of this tidal flat environment have been deposited.

Keywords

• Zagun
• Petrography
• Diagenes
• Lithofacies
• Sedimentary environment