Abstract

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Microscopic and field studies on the Lar for mation in southwest of Azarshahrin Haft- cheshme anticline section is due to separate of three part of marl, marlycarbonate and carbonate in this formation .According to microfacies and macroscopic fossils in carbonate section, open marine environment were identified from a carbonate ramp. XRD test samples related to clay marl in the low and middle part indicated existence of clay mineral such as Iliite and Cholorite from clastic origin in the part of upper and middle marl and Iliite and Smectite are diagenetic origin in the lower marl. The simultaneous presence of theses minerals in the middle marl and the lack of Smectite in this section represent of temperate climate conditions are during deposition of the middle marl. The semi-quantitative analysis of the XRD is indicating of Smectitec increasing and Iliite decreasing in the lower marl part which it may represent of a warming climate and depth sea relative increase and it was consistent with sea level change global. Important digenetic processes of identified in these formations are include: cementation, primary and secondary porosity and chert nodules formations (constituents) which the secondary porosity is more than a fracture and channel types. The existence of these fractures has created a suitable underground water aquifers in this area.

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