The role of diagenesis processes in changing the texture of carbonate rocks (an example from Shahbazan Formation, folded Zagros, South Lorestan)

Authors

1 Geology. Lurestan

2 Scientific stuff

3 Geology

4 Lorestan university

Abstract

The purpose of this research is to investigate the types of diagenesis processes and the textural changes caused by these processes in the carbonate facies of the Shahbazan Formation in Chenareh anticline section in the south-west of Lorestan. In this section, the Shahbazan Formation with a thickness of 83 meters consists of carbonate and dolomite rocks, which is placed on the Kashkan formation with a discontinuity and is covered by the Asmari formation with an erosional discontinuity. Petrographic studies on 80 sedimentary thin sections led to the identification of several diagenesis processes, including micritization, dissolution, cementation, crystallization, physical and chemical compression, and succession. Among the textural changes in the facies of this formation can be the creation of a thin micrite cover around the allochems, excessive micritization of grains, dense arrangement of grains and creation of fitted fabric, crushing, fracture and crushing. The dissolution of grains, the dissolution of grains and ground rock, cementation limited to grains and widely, types of succession, s tylolites and the removal of part of grains and rocks, the formation of stylomottle, reduced neomorphism in the shell of allochems and increase neomorphism, due to the recrystallization of micrite crystals and fractures. Based on petrographic evidence, the paragenetic sequences of Shahbazan Formation have been interpreted in four environments: marine, mete oric water, burial and uplift. Three stage diagenesis have been determined for studied sediments: early diagenesis (eogenesis), middle diagenesis (mesogenesis) and late diagenesis (telogenesis

Keywords