Interpretation paragenetic sequence of Neyzar Formation (Lower Maastrichtian) north of Mashhad

Abstract                                   

The Neyzar Formation (Early Maastrichtian ) has an extensive exposure kopet--Dagh Basin in northeast Iran. It is mainly composed of carbonate as well as siliciclastic sediments (mostly fine to medium grain sandstone and shale ). The lower boundary with the Abtalkh Formation is gradational and the upper boundary with Kalat Formation is erosional that is characterized by a paleosol horizon. Effective diagenetic processes  on the siliciclastic rocks of Neyzar Formation comprises of compaction , cementation , replacement and glauconitization, while the effective diagenetic processes on the carbonate of Neyzar Formation consists of cementation (fibrous calcite cement , equant granular cement , blocky cement , syntaxial overgrowth rim cement ), compaction , neomorphism , dissolution , micritization , hematitization , glauconitization  and formation of  fracture and calcitic viens . These  processes  operated in marine and meteoric diagenetic environments in eogenetic  , burial diagenetic environment in mesogenetic stage and burial to meteoric diagenetic environment in telogenetic stage .