کانی شناسی عناصر نادر خاکی در فسفریت های معدن جیرود، البرز غربی

نویسندگان

1 استاد گروه زمین‌شناسی، دانشکده علوم‌زمین، دانشگاه شهید بهشتی، تهران

2 کارشناس‌ارشد زمین‌شناسی اقتصادی، دانشکده علوم‌زمین، دانشگاه شهید بهشتی، تهران

3 استادیار پژوهشکده مواد و چرخه سوخت، پژوهشگاه علوم و فنون هسته‌ای، ایران

4 دانشیار گروه زمین‌شناسی، دانشکده علوم‌زمین، دانشگاه شهید بهشتی، تهران

چکیده

افق فسفات­زایی معدن جیرود در بخش مرکزی سازند جیرود در مجاورت ارتفاعات دیزین در شمال تهران قرار دارد. رسوبات این سازند با سن دونین پسین اغلب از سنگ­های آواری نظیر ماسه­سنگ، شیل­ماسه­ای و آهک­های ماسه­ای تشکیل شده است. کانی­سازی فسفریت اغلب­ در بخش شیلی آن متمرکز است. مطالعات میکروسکوپ نوری و طیف­سنج پراش پرتو ایکس (XRD) بر روی نمونه­های فسفریتی معدن جیرود نشان داد که فلوئور آپاتیت کانی­ اصلی فسفاته و کانی­های باطله همراه آن شامل کوارتز، کلسیت، پیریت، اکسیدهای آهن (اغلب گوتیت) و کانی­های رسی هستند. نتایج تجزیه کمی دقیق نقطه­ای (XPMA) نشان داد که کانی فلوئور آپاتیت، میزبان اصلی عناصر نادر خاکی در نمونه­های فسفریتی معدن جیرود است. مونازیت و در مقادیر خیلی کم زیرکن میزبان دیگر عناصر نادر خاکی در این فسفریت­ها به هستند. مقدار Ce (به عنوان نماینده عناصر نادر خاکی) در دانه­های آپاتیتی تجزیه شده از 05/0 تا 08/0 درصد وزنی متغیر است. مقدار حضور Ce و سایر عناصر نادر خاکی در آپاتیت­های رسوبی با عواملی نظیر 1) منشاء اولیه عناصر نادر خاکی؛ 2) میزان ورود این عناصر به محیط رسوب­گذاری؛ 3) مدت زمان تماس آپاتیت­ها با آب دریا در حین و بعد از تشکیل؛ 3) ترکیب شیمی آب­های بین منفذی بعد از تشکیل؛ 4) همراهی مواد آلی به عنوان یک منشا محلی؛ 5) شبکه بلوری آپاتیت­ها و تاثیر رخداد دگرجایی در فسفریت­ها مرتبط است.

کلیدواژه‌ها


عنوان مقاله [English]

Mineralogy of rare earth elements of the Jeirud phosphorites, western Alborz

نویسندگان [English]

  • M. Yazdi 1
  • M. Najafi 2
  • Kh. Khoshnoudi 3
  • M. Behzadi 4
چکیده [English]

The phosphorites horizon related to the Jeirud area is located in the central part of the Jeirud Formation, in the northern Tehran. The Late Devonian sediments of this formation is composed mainly of detrital rocks such as sandstone, sandy shale and sandy limestones. Phosphorite mineralization is mainly concentrated in the sandy shale horizon. Optical microscopy and X-ray diffraction (XRD) results showed that fluoroapatite is the main phosphate mineral and other gangues minerals composed of quartz, calcite, pyrite, iron oxides (mostly goethite) and clay minerals. The X-Ray Probe Micro Analysis (XPMA) results showed that fluoroapatite is the main host mineral for REEs. Other REE-bearing minerals include monazite and very rarely zircon. The Ce concentration (as representative of REEs) is highly variable in the decomposed apatite grains and the amount of Ce and other REEs in sedimentary apatite originating from primary rare earth elements. The concentration of REE in this phosphorites are related to the deposition environment, duration of seawater interaction during and after apatite formation, chemical composition of pore-water, organic source, apatite crystal network and the effect of the allogenic events.

کلیدواژه‌ها [English]

  • Rare Earth Elements
  • Phosphorite
  • Jeirud Formation
  • Northern Iran
Ahmad, F. Farouk. S. Abd El-Moghny M. W (2014) A regional stratigraphic correlation for the upper Campanianphosphorites and associated rocks in Egypt and Jordan. Proceedings of the Geologists’ Association, 360: 1330-1333.
Altschuler, Z. S (1980) The geochemistry of trace metals in marine phosphorites: Part 1. Characteristic abundances and enrichment. In: Bentor,Y. K. (Ed.), Marine phosphorites. The Society of economic and paleontologist and mineralogists, special publication, 29: 19-30.
Arthur Mc, J. M (1985) Francolite geochemistry and compositional controls during formation, diagenesis, metamorphism and weathering, Geochemical et Cosmochimica Acta, 49: 23-35.
Assereto, R (1963) The Paleozoic formations in Central Elburz (Iran) (preliminary note). Rivista Italiana di Paleontologia e Stratigrafia, 69: 503-543.
Assereto, R (1966) Explanatory notes on geological map of upper Djadjerud and Lar valleys (central Elburz, Iran), scale 1: 50 000. Instituto di Geologia dell, Universita di Millano, Serie G, Pubblicazione, 232: 1–86.
Awadalla, G. S (2010) Geochemistry and microprobe investigations of Abu Tartur REE-bearing phosphorite, Western Desert, Egypt. Journalof African Earth Sciences, 57: 431-443.
Abshahi, M. Jankie Pour, D. Sarafi, M. H (1988) Semi-detailed report of the phosphate exploration project (Northeast Firoozkooh) (in Persian).
Clellan Mc, G. H. and Kauwenbergh, S. J. Van (1990) Mineralogy of sedimentary apatites, Geological Society. London, 52: 23-31.
Cook, P. J. and Mc Elhinny, M. W (1979) A reevaluation of the spatial and temporal distribution of sedimentary phosphate deposits in the light of plate tectonics.Econ. Geol, 74: 315-330.
Cheshme Sari, M. Abedini, A. Alizade, A. Mousavi, S. M (2013) Mineralogy and geology of rare earth elements of Dalir phosphate horizons (South West Chalus, Mazandaran Province). Journal of Economic Geology, Mashhad Ferdowsi University of Mashhad. Iran.4:319-333 (in Persian).
Emsbo, P. McLaughlin, P. Breit, G. Edward, A. Koenig, A (2014) Rare Earth Elements in Sedimentary Phosphate Deposits: Solution to the Global REE Crisis. Gondwana Research,1346.
Gulbrandsen, R. A (1966) Chemical composition of phosphorites of the Phosphoria Formation, Geochim Cosmochim. Acta, 30: 769-778.
Ghorbani, M (2013) The economic geology of Iran, mineral deposits and natural resources. Springer Netherlands, 569 p.
Guilbert, J. M. and Park, C. F (1986) The geology of ore deposits. W. H. Freeman and Company, New York.
Halalat, H. Blurchi, M (1988) Geology of Iran, Phosphate. Geological Survey of Iran, Book editing plan (in Persian).
Kazakov, A. V (1939) the phosphate facies: Orgin of the phosphates and the geologic factors of formation of the deposits; Proc.Sci. Inst.Fert.Insectofung, 145: 1-106.
Khirekesh, Z (2016)Mineralogy and Geochemistry of phosphate rock in Firuzkuh region. MSc thesis Golestan university of Golestan. Iran (in Persian).
Khirekesh, Z. Shafiei, B (2015) Petrology and Geochronology of phosphatic horizons of Geirud Formation in Paqhaleh sections (south of Ghaemshahr, in central Alborz). 18th Iran Geological congress. Tarbiat Modares University of Tehran. Iran. (in Persian).
Mabie, C. P. and Hess, H. C (1964) Petrographic Study and Classification of Western Phosphate Ores. Department of the Interior Report of Investigations 6468, 95p.
Kelvey Mc, V. E (1963) Successful New Techniques in Prospecting for Phosphate Deposits; Science, Technology and Development U. S. Pap. for the U. N. Conf. on the application of science and technology for thebenefit of less developed areas, 163-172.
Laznicka, P (2006) Giant metallic deposits: Future sources of industrial metals. Springer-Verlag, Berlin Heidelberg, 732 pp.
Moghaddasi, J (2016) Mineralogy and rare earth elements geochemistry of Jeirud phosphate deposit in Shemshak valley in north Tehran. Geosciences, Scientific Quarterly Journal, 102: 313-324 (in Persian).
Namadmalian, A (1990) Petrology of Jeirud Phosphorite North of Tehran. MSc thesis Islamic Azad university Tehran North Branch.Iran (in Persian).
Namadmalian, A. Okhovat, M (1999) Phosphate in Iran. Geological and Mineral Exploration Organization of Iran (in Persian).
Najafi, N (2019) Mineralogy and geochemistry of rare earth elements of the phosphorites of Jeirud Mine (Western Alborz). MSc thesis Shahid Beheshti University of Tehran.Iran (in Persian).
Pourkaseb, H. Demiri, K. Zarasvandi, A. V. And Churchi, A  (2011) Geochemistry of the Sefid Kuh and Benari Phosphate Horizons in Southwestern Iran. Iranian Journal of Crystallography and Mineralogy, 4: 749-760 (in Persian).
Reynard, B. Lecuyer, C. and Grandjean, P (1999) Crystal-chemical controls on rare earth element concentrations in fossil biogenic apatites and implications for paleoenviromental reconstructions. Chem. Geol, 155: 233-241.
Rollinson, H )1993( Using geochemical data: evaluation, presentation, interpretation. Longman Scientific and Technical, 352 pp.
Shields, G. Stille, P (2001) Diagenetic constrains on the use of cerium anomalies as palaeoseawater redox proxies: An isotopic and REE study of Cambrian phosphorites. Chemical Geology, 175: 29-48.
Sharafi, A. Mahboubi, R. Moussavi-Harami, H. Mosaddegh, M. Gharaie, H. M (2014) Trace fossils analysis of fluvial to open marine transitional sediments: Example from the Upper Devonian (Jeirud Formation). Central Alborz. Iran. Palaeoworld, 23(1): 50-68.
Slansky, M (1986) Geology of sedimentary phosphates. North Oxford Academic, 210pp.