Evaluation of complications caused by burial diagenetic processes in carbonate formation(Case study, Lorestan sedimentary basin formations)

In this research, the carbonate formations of the 2nd and 3rd periods of Lorestan sedimentary basin have been studied.In this research, more than 800 sedimentary thin sections have been lithological studied.Complications caused by burial diagenesis fall into two groups:physical and chemical compression.Among the complications caused by physical compaction in carbonate rocks are types of contact between grains (point, longitudinal, convex-concave),creation of grain-to-grain fabric (fitted fabric) telescopic rotation of grains, reduction of porosity in larger grains due to the change of packing from cubic to rhombohedra grains, placing of long grains parallel to the layering surfaces, thinning of allochem shells, in-situ breakage of grains.Cracking of the shell of allochem and penetration of cement into the grains, breaking of micrite coating -grain and cement, breaking of iodic coatings, spastolization of ooids grains, crushing of peloids, falling of micrite coatings, grain fracture.Caused by the recrystallization of cement crystals, the fracture of the rock base, and the creation of porosity and plastic deformation of the grains. Complications of pressure dissolution are placed in several categories of dissolution joints, dissolution veins, stylolites and stylomottle. Among the effects of compressive dissolution caused by the effect of stylolites are grain dissolution and removal of a part of it, rock bed dissolution, cement dissolution, dissolution of dolomite crystals during burial diagenesis, dissolution of unstable grains and creation of tangled fabric due to chemical compaction.Severe and the formation of burial cement between the grains, creation of diagenetic barriers through chemical deposition of insoluble materials along it, formation of nodules of insoluble materials at the top of stylolites, multi-stage stylolitization, movement of grains relative to each other, formation of diagenetic nodules through the pointed out the formation of styloliths, displacement of fractures, dolomitization through stylolites ducts, creation of stylolites porosity and excessive entanglement of grains due to intense pressure-dissolution action