Mineralogical characterization and evaluation of chromite ore in Grevena and Kozani Vourinos massif, Western Macedonia, Greece

Apostolos Baklavaridis¹, Konstantinos Vatalis¹, Vayos Karayannis¹, Ploutarchos-Nikolaos Benetis¹, Georgios Charalampides¹

¹University of Western Macedonia, Kozani, 50100, Greece

Min. miner. depos. 2021, 15(1):11-18

https://doi.org/10.33271/mining15.01.011

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ABSTRACT

Purpose. Chromite samples from Aetoraches mine area in the southern part of the Vourinos complex in Western Macedonia, Greece were examined from mineralogical-geochemical perspective.

Methods. Χ-ray Diffraction (XRD) mineral phase analysis, elemental Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) analysis and Thermogravimetry/Differential Thermogravimetry (TG/DTG) were carried out.

Findings. The XRD results showed that all the samples contain mainly magnesium- and aluminum-chromite (“aluminum-picrochromite”) phases, along with forsterite (magnesian olivine), serpentine and chlorite occurrences. Based on the SEM-EDS results, the computed average chemical formula indicative of this specific chromite type is: (Fe_0.4 Mg_0.6) (Cr_1.6 Al_0.4/)O₄. The TG-DTG weight losses found to be in the range of 4.4-14.36%, at temperatures between 600 and 750°C, indicated the presence of the hydroxyl-rich silicate minerals, serpentinite and chlorite, in agreement to the Loss of Ignition (LOI) results. The mineral phases detected in the present analyses appear in the dunite/diorite/harzburgite/peridotite main rocks of the ophiolitic complex that hosts the chromite ore.

Originality.In the current research, an original characterization, via thorough elemental, phase and thermal analysis, is carried out aiming to enlighten the geochemistry aspects of the Vourinos chromite complex, Region of Western Macedonia, Greece, particularly of easily accessible and exploitable chromite deposits of the Aetoraches mine area.

Practical implications. The chromite mineral, and especially the metallurgical type, is of substantial importance in metal industry. In that sense, the findings of the present investigation of chromite purity and mineral structure is a prerequisite for future exploitation of the Aetoraches chromite deposits in particular and broadly for the ongoing exploitation of chromite ore in the Vourinos complex, situated in Region of Western Macedonia, Greece, an area with high unemployment and rather slow economic growth.

Keywords: chromite ore, Vourinos massif, Aetoraches mine area, mineralogical characterization, geochemistry, XRD, SEM-EDS, TG/DTG

REFERENCES

Dick, H.J.B., & Bullen, T. (1984). Chromian spinel as a petrogenetic indicator in abyssal and alpine-type peridotites and spatially associated lavas. Contributions to Mineralogy and Petrology, 86(1), 54-76.https://doi.org/10.1007/BF00373711
Economou-Eliopoulos, M. (1996). Platinum-group element distribution in chromite ores from ophiolite complexes: implications for their exploration. Ore Geology Reviews, 11(6), 363-381.https://doi.org/10.1016/S0169-1368(96)00008-X
Konstantopoulou, G., & Economou-Eliopoulos, M. (1991). Distribution of platinum-group elements and gold within the Vourinos chromitite ores, Greece. Economic Geology, 86(8), 1672-1682. https://doi.org/10.2113/gsecongeo.86.8.1672
Bacuta, G.C., Kay, R.W., Gibbs, A.K., & Lipin, B.R. (1990). Platinum-group element abundance and distribution in chromite deposits of the Acoje Block, Zambales Ophiolite Complex, Philippines. Journal of Geochemical Exploration, 37(1), 113-145. https://doi.org/10.1016/0375-6742(90)90086-P
Cina, A., Caselli, H., & Goci, L. (1986). Chromites in the ophiolites of Albanides. Metallogeny of Ophiolites, 107-128.
Economou, M., Dimou, E., Economou, G., Migiros, G., Vacondios, I., Grivas, E., & Dabitzias, S. (1986). Chromites: UNESCO’s IGCP-197 Project, Metallogeny of Ophiolites. Theophrastus Publications.
Zhou, M.F., & Robinson, P.T. (1997). Origin and tectonic environment of podiform chromite deposits. Economic Geology, 92(2), 259-262. https://doi.org/10.2113/gsecongeo.92.2.259
Tindle, A.G., & Pearce, J.A. (1983). Assimilation and partial melting of continental crust: evidence from the mineralogy and geochemistry of autoliths and xenoliths. LITHOS, 16(3), 185-202. https://doi.org/10.1016/0024-4937(83)90023-3
Grivas, E., Rassios, A., Konstantopoulou, G., Vacondios, I., & Vrahatis, G. (1993). Scientific communications: Drilling for “blind” podiform chrome orebodies at voidolakkos in the vourinos ophiolite complex, Greece. Economic Geology, 88(2), 461-468. https://doi.org/10.2113/gsecongeo.88.2.461
Economou-Eliopoulos, M., & Vacondios, I. (1995). Geochemistry of chromitites and host rocks from the Pindos ophiolite complex, northwestern Greece. Chemical Geology, 122(1-4), 99-108. https://doi.org/10.1016/0009-2541(94)00154-Z
Rassios, A.E. (2004). A geologist’s guide to West Macedonia. Grevena, Greece: The Grevena Development Agency, 119 p.
Rassios, A., Smith, A., & Kostopoulos, D. (2009). Ophiolites 2008 Guidebook: Link between the Mesohellenic Ophiolites and the Pelagonian Margin. Journal of the Virtual Explorer, (34), 1. https://doi.org/10.3809/jvirtex.2009.00213
Kapsiotis, A.N. (2015). Alteration of chromitites from the Voidolakkos and Xerolivado mines, Vourinos ophiolite complex, Greece: Implications for deformation-induced metamorphism. Geological Journal, 50(6), 739-763. https://doi.org/10.1002/gj.2590
Tzamos, E., Filippidis, A., Michailidis, K., Koroneos, A., Rassios, A., Grieco, G., Pedrotti, M., & Stamoulis, K. (2016). Mineral chemistry and formation of awaruite and heazlewoodite in the xerolivado chrome mine, Vourinos, Greece. Bulletin of the Geological Society of Greece, 50(4), 2047-2056. https://doi.org/10.12681/bgsg.11951