نویسندگان
1 گروه زمین شناسی، دانشکده علوم زمین، دانشگاه شهید بهشتی
2 پژوهشکده مواد و چرخه سوخت، پژوهشگاه علوم و فنون هستهای، ایران
3 گروه زمین شناسی، دانشکده علوم زمین، دانشگاه شهید بهشتی، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The phosphate horizon related to the Jeiroud mine is located in the central part of the Jeiroud Formation in the vicinity of the Dizin Heights in northern Tehran. The Late Devonian sediments of this formation composed of detrital rocks such as sandstone, sandy shale and sandy limestones. Phosphorite mineralization is mainly concentrated in the shale horizon. Optical Microscopy and X-ray diffraction (XRD) analysis on phosphorite samples showed that fluoroapatite is the main phosphate mineral and quartz, calcite, pyrite; iron oxides (mostly goethite) and clay minerals are gangues. The X-Ray Probe Micro Analysis (XPMA) results showed that fluoroapatite is the main host of REEs in these phosphate samples. Other hosts of REEs in these phosphates can be monazite and very rarely zircon. The Ce concentration (as representative of REEs) is highly variable in the decomposed apatite grains and the amount of this element and other REEs in sedimentary apatite originating from primary rare earth elements, which is related to the rate of entry of these elements into the deposition environment, duration of contact with seawater during and after the formation of apatite, the chemical composition of the pore water after formation, organic matter accompaniment as a local source, apatite crystal network and the effect of the allogenic events on phosphates.
کلیدواژهها [English]
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