Mineralogy, Geochemistry, and Fluid Inclusion Microthermometry of Apatite and Rare Earth Element Minerals in the Esfordi Deposit, NE of Bafq, Yazd Province

Document Type : Research Article

Authors

• Kiamars Hosseini
• Mohammad Ali Rajabzadeh

Department of Earth Sciences, Faculty of Sciences, Shiraz University, Shiraz, Iran

10.22067/econg.v13i1.84702

Abstract

Introduction
REE should be evaluated in rocks and minerals due to their behavior in complex geochemical processes leading to their use as tracers in geochemical environments. In addition, the lack of economic concentration of these elements is related to their contribution in rock forming minerals. Thus, high levels of technology and costs are essential for their extraction. However, REE minerals can be formed under special geological conditions. In this regard, the Esfordi iron-phosphate deposit is interesting both economically and scientifically. The present study is aimed at determination of rare earth element mineral types, along with their occurrence in this deposit by using mineralogy, geochemistry, and fluid inclusion microthermometry methods.
 
Method of study
A total of 42 apatite samples were taken from different lithological units and ore-bearing veins. Following petrographic observations, 10 and 6 representative samples were analyzed using SEM and XRD methods in the Iran Minerals Processing Research Center, respectively. Geochemical properties of apatite and rare earth element minerals were determined on 8 samples using LA-ICP-Ms at the University of Tasmania, Australia. Moreover, the same was done for 6 samples using EPMA at the Geo Forschungs Zentrum Telegrafenberg of Potsdam University, Germany. In addition, 12 samples of apatite were considered for evaluating petrography of fluid inclusions. Microthermometry of the fluid inclusions was conducted on two second generation apatite samples associated with massive phosphate mineralization zone and magnetite mineralization zone in the laboratory of the Geological Survey and Mineral Explorations of Iran. Phases changes in fluid inclusions in heating and freezing tests under a Linkam THM600 microscope with TP94 Thermal Controller and LNP Type Cooler mounted on Zeiss microscope, with an accuracy of ±0.5 ˚C was performed. Given that no phase changes were produced in some inclusions (melt inclusions) up to the temperature of 600°C, two samples of apatite were studied using the Linkam TS1400XY microscope in Lithosphere Fluid Research Lab of the Department of Petrology and Geochemistry at Eötvös Loránd University, Budapest, Hungary.
 
Results
Mineralogical studies of apatite in Esfordi revealed the extensive presence of monazite and a lesser amount of xenotime. The results indicate two generations of monazite in this deposit. The first generation is observed as inclusions within the apatites, while the second generation occurs along the fractures of apatites. Monazite inclusions are abundant in the dark phase of host apatites. Based on geochemical data, the second generation of monazite is enriched in La, La/Ce, Nd, and Pr compared to the first generation. Furthermore, strong negative correlation coefficients were observed between Ca, P, and ΣREE, while a positive correlation was reported between Si and P in apatite and monazite. Chondrite normalized spider diagrams indicate a negative slope (LREE/HREE>1) in all of the samples. Moreover, a strong negative correlation was observed between Sr and Y in the studied apatite and monazites. Fluid inclusions within the apatites were classified into eight groups: a) one-phase gaseous inclusions, b) one-phase liquid inclusions, c) two-phase liquid rich inclusions (L+V), d) two-phase gas-rich inclusions (V+L), e) two-phase liquid- solid inclusions (L+V), f) three-phase inclusions (V-L-S), g) three-phase CO₂ bearing inclusions associated with formation of clathrate, and h) melt inclusions. The composition of the fluid inclusions is plotted in magmatic and hydrothermal fields. The salinity of most of the inclusions is low to medium (5-21 wt.% NaCl) and homogenization temperature ranges from 250 to 350˚C. Also, a limited number of fluid inclusions were homogenized in the range of 378-486 ˚C, indicating high salinity (43 to 54 wt.% NaCl). The fluid trapping depths were measured to be in the range 100-1700 m.
 
Discussion
The Esfordi iron-apatite deposit is located NE of Bafq, Yazd province and it hosts three types of apatite mineralization in massive, vein, and disseminated forms, as well as REE-bearing minerals. Periodic variations in mineralizing fluid is evidenced by changes in REE content of the studied minerals. The presence of monazite in dark phases of the host apatite mineral indicates leaching of REE from the host apatite and redeposition during the nucleation of monazite grains (Heidarian et al., 2017). Mineralogical data indicated that the apatites are of the fluorapatite type with minor contents of chloride (Rajabzadeh et al., 2013). The quantities of Sr and Y in the studied minerals indicate a strong negative correlation, consistent with magmatic differentiation. In addition, the concentrations of Mn, Sr, and Y support the granitoid origin of the Esfordi deposit (Belousova et al., 2002). Microthermometric data plotted on magmatic and hydrothermal fields indicated that mixing fluids and boiling are the important factors in mineralization. Upon the obtained data of the present study, main parts of the Esfordi iron phosphate deposit have been formed at temperatures ranging from 146 to 486˚C and depths of 100 to 1700 m.
 
Acknowledgements
The authors appreciate Shiraz University Research Council for their support of this work. The Director General and personnel of the Esfordi Mine Company are acknowledged for their assistance in the field works.
 
References
Belousova, E.A., Griffin, W.L., O’Reilly, S.Y. and Fisher, N.I., 2002. Apatites as indicator mineral for mineral exploration: trace-element compositions and their relationship to host rock type. Journal of Geochemical Exploration, 76(1): 45–69. https://doi.org/10.1016/S0375-6742(02)00204-2
Heidarian, H., Alirezaei, S. and Lentz, D., 2017. Chadormalu Kiruna-type magnetite–apatite deposite, Bafq district, Iran: Insights in to hydrothermal alteration and petrogenesis from geochemical, fluid inclusion and sulfur isotope data. Ore Geology Reviews, 83(7): 43–62. https://doi.org/10.1016/j.oregeorev.2016.11.031
Rajabzadeh, M.A., Hoseini. K. and Moosavinasab. Z., 2013. Mineralogical and geochemical studies on apatites and phosphate host rocks of Esfordi deposit, Yazd province, to determine the origin and geological setting of the apatite. Journal of Economic Geology, 6(2): 331–353. (in Persian with English abstract) https://dx.doi.org/10.22067/ECONG.V6I2.20956 

Keywords

• Mineralogy
• Geochemistry
• Microthermometry
• Apatite
• Monazite
• Rare Earth Element Minerals
• Esfordi deposit
• Bafq

20.1001.1.20087306.1400.13.1.3.7

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References

Andreoli, M.A.G., Smith, C.B., Watkeys, M., Moore, J.M., Ashwal, L.D. and Hart, R.J., 1994. The geology of the Steenkampskraal monazite deposit, South Africa, Implications for REE-Th-Cu mineralization in charnockite-granulite terranes. Economic Geology, 89(5): 994–1016. https://doi.org/10.2113/gsecongeo.89.5.994

Belousova, E.A., Griffin, W.L., O’Reilly, S.Y. and Fisher, N.I., 2002. Apatites as indicator mineral for mineral exploration: trace-element compositions and their relationship to host rock type. Journal of Geochemical Exploration, 76(1): 45–69. https://doi.org/10.1016/S0375-6742(02)00204-2

Boomeri, M., 2012. Rare earth minerals in Esfordi magnetite-apatite ore deposit, Bafq district. Journal of Geosciences, 22(85):71–82. http://dx.doi.org/10.22071/gsj.2012.54023

Borumandi, H., 1973. Petrographische und lagerstattenkundliche untersuchungen der Esfordi–formation zwischen Mishdovan and Kushk bie Bafq, Zentral Iran. Ph.D. Thesis, RWTH Aachen University, Aachen, Germany, 174 pp.

Boynton, W.V., 1985. Cosmo chemistry of the rare earth elements: Meteorite studies. In: P. Henderson (Editor), Rare Earth Element Geochemistry, (Developments in Geochemistry2). Elsevier, Amsterdam, pp. 115–1522. https://doi.org/10.1016/B978-0-444-42148-7.50008-3

Edfelt, A., 2007. The Tjarrojakka Apatite-Iron and Cu (-Au) deposits, Northern Sweden, Division of Ore Geology and Applied Geophysics. Ph.D. Thesis, Lulea University of Technology, Lulea, Sweden, 230 pp.

Fan, H.R., Groves, D.I., Mikucki, E.J. and Mc Naughton, N.J., 2000. Contrasting fluid types at the Nevoria gold deposit in the Southern Cross greenstone belt, Western Australia: Implications of auriferous fluids depositing ores within and Archean banded iron- formation. Economic Geology, 95(7): 1527–1536. https://doi.org/10.2113/gsecongeo.95.7.1527

Frietsch, R. and Perdahl, J.A., 1995. Rare earth elements in apatite and magnetite in kiruna– type iron ores and some other iron ore types. Ore Geology Reviews, 9(6): 489–510. https://doi.org/10.1016/0169-1368(94)00015-G

Harlov, D.E., 2015. Apatite: A fingerprint for metasomatic processes. Elements, 11(3): 171–176. https://doi.org/10.2113/gselements.11.3.171

Harlov, D.E., Anderson, U.B., Forster, H.J., Nystrom, J.O., Dulski, P. and Broman, C., 2002. Apatite–monazite relations in the kiirunavaara magnetite- apatite ore, northern Sweden. Chemical Geology, 191(1–3): 47–72. https://doi.org/10.1016/S0009-2541(02)00148-1

Harlov, D.E. and Forster, H.J., 2003. Fluid-induced nucleation of (Y+REE)-phosphate minerals within apatite: Nature and experiment. Part II, Fluorapatite. American Mineralogist, 88(8–9): 1209–1229. https://doi.org/10.2138/am-2003-8-905

Harlov, D.E., Wirth, R. and Forster, H.J., 2005. An experimental study of dissolution- reprecipitation in fluorapatite: fluid infiltration and the formation of monazite. Contributions to Mineralogy and Petrology, 150(3): 268–286. https://doi.org/10.1007/s00410-005-0017-8

Heidarian, H., 2013. Investigation of genetic relations between mimeralization, host rock and metasomatic alterations in Chadormalu iron deposit, Central Iran. M.‌Sc. Thesis, Shahid Beheshti University, Tehran, Iran, 219 pp. (in Persian with English abstract)

Heidarian, H., Alirezaei, S. and Lentz, D., 2017. Chadormalu Kiruna-type magnetite–apatite deposite, Bafq district, Iran: Insights in to hydrothermal alteration and petrogenesis from geochemical, fluid inclusion and sulfur isotope data. Ore Geology Reviews, 83(7): 43–62. https://doi.org/10.1016/j.oregeorev.2016.11.031

Heidarian, H., Lentz, D., Alirezaei, S., Peighambari, S. and Hall, D., 2016. Using the chemical analysis of magnetite to constrain various stages in the formation and genesis of the Kiruna-type chadormalu magnetite-apatite deposit, Bafq district, Central Iran. Mineralogy and Petrology, 110(6): 927–942. https://doi.org/10.1007/s00710-016-0440-8

Hooshmandzadeh, A., Nabavi, M.J. and Hamdi, B., 1988. Precambrian-Lower Cambrian rocks in Iran. 1st Conference of Investigation on Resources and Mineral Potential, Yazd University, Yazd, Iran. (in Persian)

Hsieh, P.S., Chen, C.H., Yang, H.J. and Lee, C.Y., 2008. Petrogenesis of the Nanling Mountains granites from South China: Constraints from systematic apatite geochemistry and whole-rock geochemical and Sr–Nd isotope compositions. Journal of Asian Earth Sciences, 33(5-6): 428–451. https://doi.org/10.1016/j.jseaes.2008.02.002

Hughes, J.M. and Rakovan, J., 2002. The crystal structure of apatite, Ca5(PO4) 3 (F, OH, Cl). Reviews in Mineralogy and Geochemistry, 48(1): 1–12. https://doi.org/10.2138/rmg.2002.48.1

Jami, M., 2005. Geology, Geochemistry and Evolution of the Esfordi Phosphate– Iron deposit, Bafq area, Central Iran. Ph.D. Thesis, University of New South Wales, Sydney, Australia, 220 pp.

Jami, M., Dunlop, A.C. and Cohen, D.R., 2007. Fluid inclusion and stable isotope study of the Esfordi apatite-magnetite deposit, Central Iran. Economic Geology, 102(6): 1111–128. http://dx.doi.org/10.2113/gsecongeo.104.1.140

Kanazawa, Y. and Kamitani, M., 2006. Rare earth minerals and resources in the world. Journal of Alloys and Compounds, 408(1): 1339–1343. https://doi.org/10.1016/j.jallcom.2005.04.033

 Kesler, S.E., Reich, M. and Jean, M., 2007. Geochemistry of fluid inclusion brines from Earths oldest Mississippi Valley- type (MVT) deposits. Chemical Geology, 237(3-4): 234–248. https://doi.org/10.1016/j.chemgeo.2006.11.001

Mao, M., Rukhlov, A.S., Rowins, S.M., Spence, J. and Coogan, L.A., 2016. Apatite trace element compositions: a robust new tool for mineral exploration. Economic Geology, 111(5): 1187–1222. https://doi.org/10.2113/econgeo.111.5.1187

Mariano, A.N., 1989. Economic geology of Rare earth elements. In: B.R. Lipin and G.A. McKay (Editors), Geochemistry and mineralogy of rare earth elements. Mineralogical Society of America, Washington, D.C, pp. 309–337. https://doi.org/10.1515/9781501509032-014

Paknejad, H., 1991. Complementary exploration of Esfordi deposit. Geological Survey of Iran, Tehran, Report 11, 89 pp. (in Persian)

Pan, Y. and Fleet. M.E., 2002. Compositions of the apatite-group minerals: Substitution mechanisms and controlling factors. In: M.J. Kohn, J. Rakovan and J.M. Hughes (Editors), Phosphates: Geochemical, geobiological and material importance. Mineralogical Society of America, Washington, D.C, pp. 13–49. https://doi.org/10.2138/rmg.2002.48.2

Rajabzadeh, M.A., Hoseini. K. and Moosavinasab. Z., 2013. Mineralogical and geochemical studies on apatites and phosphate host rocks of Esfordi deposit, Yazd province, to determine the origin and geological setting of the apatite. Journal of Economic Geology, 6(2): 331–353. (in Persian with English abstract) https://dx.doi.org/10.22067/ECONG.V6I2.20956  

Ramezani, J. and Tucker, R.D., 2003. The Saghand region, Central Iran: U-Pb geochronology, petrogenesis and implications for Gondwana tectonics. American Journal of Science, 303(7): 622–665. https://dx.doi.org/10.22067/ECONG.V6I2.20956  

Roedder, E., 1984. Inclusion sample selection, preparation, petrography and photography. In: P.H. Ribbi (Editor), Fluid Inclusions. Mineralogical Society America, Washington, D.C, pp. 149–180. https://doi.org/10.1515/9781501508271-009

Roeder, P.L., MacArthur, D., Ma, X.P., Palmer. G.R. and Mariano, A.N., 1987. Cathodoluminescence and microprobe study of rare-earth elements in apatite. American Mineralogist, 72(7–8): 801–811. Retrieved March 03, 2017 from http://www.minsocam.org/ammin/AM72/AM72_801.pdf

Ronsbo, J.G., 1989. Coupled substitution involving REEs and Na and Si in apatites in alkaline rocks from the Ilímaussaq intrusion, South Greenland, and the petrological implications. American Mineralogist, 74(7–8): 896–901. Retrieved March 02, 2017 http://www.minsocam.org/ammin/am74/am74_896.pdf

Sabet-Mobarhan-Talab, A., Alinia, F., Ghannadpour, F. and Hezarkhani, A.S.S., 2015. Geology and geochemistry, and some genetic discussion of the Chadormalu iron oxide apatite deposite, Bafg District, Central Iran. Arabian Journal of Geosciences, 8(10): 8399–8418. https://doi.org/10.1007/s12517-015-1813-8

Samani, B., 1993. Saghand formation, a riftogenic unit of upper Precambrian in central Iran. Journal of Geosciences, 2(6): 32–45. http://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=6501166

Schandl, E.S. and Gorton, M.P., 2004. A textural and geochemical guide to the identification of hydrothermal monazite: Criteria for selection of samples for dating epigenetic hydrothermal ore deposits. Economic Geology, 99(5): 1027–1035. https://doi.org/10.2113/gsecongeo.99.5.1027

Shepherd, T.J., Rankin, A.H. and Alderton, D.H.M., 1985. A practical guide to fluid inclusion studies. Blackie Press, London, 239 pp.

Soheili, M. and Mahdavi, M.A., 1991. Geological map of Esfordi, scale 1:100,000. Geological Survey of Iran.

Sverjensky, D.A., 1984. Europium redox equilibria in aqueous solution. Earth and Planetary Science Letters, 67(1): 70–78. https://doi.org/10.1016/0012-821X(84)90039-6

Torab, F.M., 2008. Geochemistry and metallogeny of magnetite-apatite deposits of the Bafq Mining District, Central Iran. Ph.D. Thesis, Clausthal University of Technology, Clausthal, Germany, 131 pp.

Townsend, K.J., Miller, C.F.D., Andrea, J.L., Ayers, J.C., Harrison, T.M. and Coath, C.D., 2001. Low temperature replacement of monazite paragenesis in the Ireteba granite, southern Nevada, Geochornological implication. Chemical Geology, 172(1–2): 95–112. https://doi.org/10.1016/S0009-2541(00)00238-2

Whitney, D.L. and Evans, B.W., 2010. Abbreviations for names of rock-forming minerals. American Mineralogist, 95(1): 185–187. https://doi.org/10.2138/am.2010.3371

Wilkinson, J.J., 2001. Fluid inclusion in hydrothermal ore deposits. Lithos, 55(1–4): 229-272. https://doi.org/10.1016/S0024-4937(00)00047-5

Williams-Jones, A.E., Schrijver, K., Doig, R. and Sangster, D.F., 1992. A model for epigenetic Ba-Pb-Zn mineralization in the Appalachian Trust Belt Quebec: Evidence from fluid inclusions and isotopes. Economic Geology, 87(1): 154–174. https://doi.org/10.2113/gsecongeo.87.1.154

Yermacov, N.P. (translated by Sokoloff, V.P.), 1965. Research on the nature of mineral-forming solutions with special reference to data from fluid inclusions, Permagon Press, Oxford, 743 pp.

Zabihi, R. and Hosseini, K., 2016. Mineralogical, geochemical and radioisotopes studies on the REE minerals and apatites from Esfordi and Choghart deposite, NE of Bafgh. 34th National & the 2nd International Geosciences Congress, Geological Survey of Iran, Tehran, Iran. (in Persian with English abstract)