رخساره ها و محيطهاي رسوبي سازند بادامو در اطراف زرند كرمان

Facies and Depositional Environments of the Badamu Formation in Zarand area

Badamu Formation, exposed in Zarand area (N. W. Kerman), is mainly composed of limestone and shale (Late Toarcian-Middle Bajucian). In this area, Badamu Formation with a basal conglomerate conformably overlays Ab-e-Haji Formation (the second formation of Shemshak Group) and is underlaid abruptly (sometimes gradually) by the Hojedk Formation (the fourth formation of Shemshak Group). Field and laboratory studies indicate four facies groups in Badamu Formation. Facies group A includes mudstone wackestone with sponge spicules, limemudstone, bioclast wackestone and bioclast intraclast wackestone/packestone microfacies which suggests an open marine environment. Facies group B includes bioclast grainstone, ooid grainstone, oncoid grainstone, bioclast intraclast grainstone, and sandy ooid bioclast grainstone microfacies which indicates barrier and beach environment (sandy ooid bioclast grainstone). Facies group C contains bioclast oncoid wackestone/packestone, bioclast wackestone/packestone and silty fossiliferous mudstone microfacies which suggests a lagoonal environment. Facies group D incudes conglomerate, sedarenite/phyllarenite and quartzarenite/subchertarenite microfacies deposited during the progression of the Badamu Sea at the base of the Badamu Formation in a barrier/beach environment.Based on the study of vertical and lateral facies variations and its comparison with recent sedimentary environments a sedimentary model is proposed for the study area. This model shows that a barrier facies divides the sedimentary environment into a Semi-restricted open marine and a lagoon environments. The presence of distal open marine facies and resedimented facies show that the carbonate platform of Badamu is similar to the Florida continental shelf. Sedimentary model presented for the Mozduran and Chaman-Bid Formations could be the same as ancient model of the Badamu Formation.