New insights into mineralogy and geochemistry of allanite-bearing Mediterranean coastal sands from Northern Greece
Allanite-bearing black coastal sands of Kavala (N. Greece) were studied using a combination of single-crystal XRD, EMPA, mu-XRF, bulk ICP-MS, LA-ICP-MS, mu-XANES and gamma-ray spectrometry. The sands are rich in REE (Sigma REE + Y: 4010 to 10,810 mg/kg), Th (236-1205 mg/kg) and other critical metals...
| Autores: | , , , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | Brasil |
| Institución: | Universidade Estadual Paulista (UNESP) |
| Repositorio: | Repositório Institucional da UNESP |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.unesp.br:11449/196292 |
| Acceso en línea: | http://dx.doi.org/10.1016/j.chemer.2019.05.002 http://hdl.handle.net/11449/196292 |
| Access Level: | acceso abierto |
| Palabra clave: | Kavala Beach placer REE Thorium Allanite mu-XRF SR-XANES |
| Sumario: | Allanite-bearing black coastal sands of Kavala (N. Greece) were studied using a combination of single-crystal XRD, EMPA, mu-XRF, bulk ICP-MS, LA-ICP-MS, mu-XANES and gamma-ray spectrometry. The sands are rich in REE (Sigma REE + 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) (Ti0.031Fe1.089+3Al1.880) (Si-2.906Al0.094O12) (OH). The mu- 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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