The site location and geometry of trace amounts of dysprosium (299 ppm) in a natural melanite garnet from carbonatitic rocks have been studied by high energy fluorescence-detected X-ray Absorption Fine-Structure Spectroscopy (XAFS). Measurements done at the Dy K-edge (53789 eV), show that Dy is hosted in the dodecahedral X site. The local geometry of Dy, which is compatible with its ionic radius, is compared to that of Ca, the major element at the X site, as determined by single-crystal X-ray refinement, and with that of other trace RE elements as determined by previous XAFS studies. This work confirms that fluorescence XAFS at high energy is capable of providing coordination and local site geometry of heavy trace-elements in complex minerals. This information is important for Earth Sciences, and especially for geochemical modelling of trace-element incorporation and partitioning
Changes in the local coordination of trace rare earth elements in garnets by high-energy XAFS: new data on dysprosium / S. QUARTIERI; M. C. DALCONI; BOSCHERINI F.; R. OBERTI; F. DACAPITO. - In: PHYSICS AND CHEMISTRY OF MINERALS. - ISSN 0342-1791. - STAMPA. - 31:(2004), pp. 162-170. [10.1007/s00269-003-0377-4]
Changes in the local coordination of trace rare earth elements in garnets by high-energy XAFS: new data on dysprosium
BOSCHERINI, FEDERICO;
2004
Abstract
The site location and geometry of trace amounts of dysprosium (299 ppm) in a natural melanite garnet from carbonatitic rocks have been studied by high energy fluorescence-detected X-ray Absorption Fine-Structure Spectroscopy (XAFS). Measurements done at the Dy K-edge (53789 eV), show that Dy is hosted in the dodecahedral X site. The local geometry of Dy, which is compatible with its ionic radius, is compared to that of Ca, the major element at the X site, as determined by single-crystal X-ray refinement, and with that of other trace RE elements as determined by previous XAFS studies. This work confirms that fluorescence XAFS at high energy is capable of providing coordination and local site geometry of heavy trace-elements in complex minerals. This information is important for Earth Sciences, and especially for geochemical modelling of trace-element incorporation and partitioningI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
