New insights into mineralogy and geochemistry of allanite-bearing Mediterranean coastal sands from Northern Greece
Tzifas, I.T.; Papadopoulos, A.; Misaelides, P.; Godelitsas, A.; Göttlicher, J.; Tsikos, H.; Gamaletsos, P.N.; Luvizotto, G.; Karydas, A.G.; Petrelli, M.; Noli, F.; Kantarelou, V.; Kontofakas, A.; Hatzidimitriou, A. (2019). New insights into mineralogy and geochemistry of allanite-bearing Mediterranean coastal sands from Northern Greece. Chemie der Erde-Geochemistry 79(2): 247-267. https://dx.doi.org/10.1016/j.chemer.2019.05.002
In: Chemie der Erde-Geochemistry: Jena. ISSN 0009-2819; e-ISSN 1611-5864, more
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| Keyword |
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| Author keywords |
Kavala; Beach placer; REE; Thorium; Allanite; mu-XRF; SR-XANES |
| Authors | | Top |
- Tzifas, I.T.
- Papadopoulos, A., more
- Misaelides, P.
- Godelitsas, A.
- Göttlicher, J.
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- Tsikos, H.
- Gamaletsos, P.N., more
- Luvizotto, G.
- Karydas, A.G.
- Petrelli, M.
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- Noli, F.
- Kantarelou, V.
- Kontofakas, A.
- Hatzidimitriou, A.
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| Abstract |
Allanite-bearing black coastal sands of Kavala (N. Greece) were studied using a combination of single-crystal XRD, EMPA, μ-XRF, bulk ICP-MS, LA-ICP-MS, μ-XANES and γ-ray spectrometry. The sands are rich in REE (ΣREE + Y: 4010 to 10,810 mg/kg), Th (236–1205 mg/kg) and other critical metals such as Nb, Ta and Co. The main REE- and Th-hosts are allanite and titanite. The allanite unit cell parameters were calculated whereas its formula was found to be (REE0.470Ca1.499Th0.031) (Ti0.031Fe+31.089Al1.880) (Si2.906Al0.094O12) (OH). The μ-XANES spectra showed that LREE are present in trivalent oxidation state. Analyses of the non-magnetic sand fractions showed higher LREE (12,470 mg/kg) due to accumulation of allanite. The materials showed elevated radioactivity ranging from 885 ± 13 to 3467 ± 20 Bq/kg. The obtained results provide new insights on the provenance of the sands, the abundance of REE, Th, and other immobile elements, and offer new clues for potential exploration and exploitation. |
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