نویسندگان
1 گروه زمینشناسی، دانشگاه لرستان، خرمآباد، ایران
2 دانشآموخته مقطع دکتری، کارشناس آزمایشگاه مرکزی دانشگاه لرستان، خرمآباد، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In this study, the microfacies, depositional environment, and burial history of carbonate deposits of the Asmari Formation in the Khorramabad anticline have been investigated.This 115-meter-thick with lithological thin bedded, medium bedded and thick bedded limestones is located on the northern flank of the Khorramabad anticline (Zarrinchogha region).In this section, the lower and upper boundaries of the Asmari Formation are paraconformity with the Shahbazan and Gachsaran formations, respectively. Microscopic studies on 115 thin-section samples and field studies ultimately led to the identification of eight microfacies. These microfacies include fossiliferous mudstone, intraclastic dolomitized mudstone, and fenestral mudstone, wackestone to packstone pelloidal, bioclastic wackestone, packstone bioclastic, grainstone pelloidal, and bioclastic grainstone. Evidence such as fenestral mudstone, abundance of non-porous benthic foraminifera with porcelains shells in the mudstone texture, abundance of red algae, silt-sized detrital quartz grains, and weak to moderate sediment sorting indicate that these microfacies were deposited in three intertidal, lagoon, and barrier facies belts of an internal ramp.The dominant diagenetic processes in these microfacies include micritization, increasing and decreasing neomorphism, cementation (rim cement isopachous, blocky, drusy, and poikilotopic cement), physical and chemical compaction, fabric-dependent and non-fabric-dependent dissolution of the rock, and the creation of intergranular, intragranular, and pore porosity, fracture, stylolitic, and moldic, and replacement in the form of pyritization, silicification, and dolomitization. These processes have occurred in four environments: marine, freshwater, burial, and upwelling, in which three stages of initial, intermediate, and final diagenesis have been identified.
کلیدواژهها [English]
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