Rare-Earth Elements REE

The REE characterics of calcite from the Au-Ag type are variable. For example, calcites from Sado Au-Ag vein, one of the largest Au-Ag deposits in Japan have both signatures of meteric water and magmatic (or igneous) contributions. Positive Eu anomaly is only found in caleite containing low REE from Au-Ag type (Seigoshi deposit) (Shikazono, unpublished). 

The rare earth elements (REE) are the most useful of all trace elements and REE studies have important applications in igneous, sedimentary and metamorphic petrology. The REE comprise the series of metals with atomic numbers 57 to 71 — La to Lu (Table 4.4). In addition, the element Y with an ionic radius similar to that of the REE Ho is sometimes included. Typically the low-atomic-number members of the series are termed the light rare earths (LREE), those with the higher atomic 

Atomic number Name Symbol lonk radius for eight-fold coordination  

The rare earths (REE) also named lanthanides (Ln) are a fascinating group of elements the optical properties of which arise from the iimer f-electrons which are starting with one in Cerium and terminate with thirteen in Ytterbium. The 

Gaft et al.. Modern Luminescence Spectroscopy of Minerals and Materials, Springer Mineralogy, DOI 10.1007/978-3-319-24765-6 5 

The crystal field model may also provide a calciflation scheme for the transition probabilities between levels perturbed by the crystal field. It is so called weak crystal field approximation. In this case the crystal field has little effect on the total Hamiltonian and it is regarded as a perturbation of the energy levels of the free ion. Judd and Ofelt, who showed that the odd terms in the crystal field expansion might connect the 4/ configuration with the 5d and 5g configurations, made such calculations. The result of the calculation for the oscillator strength, due to a forced electric dipole transition between the two states makes it possible to calculate the intensities of the lines due to forced electric dipole transitions. 

Tx are components of a tensor operator, the explicit expression for them being 

R iR iii are the radial parts of the wave function in the and configuration, respectively. 

---

Rare earth elements (REE). Analytical results of REE contents of hydrothermally altered volcanic rocks in Kuroko mine area and Kuroko ores are summarized as follows (Shikazono, 1999a) (Fig. 1.46). 

The rare earth elements (REE) form a group of elements that have coherent geochemical behaviour due to their trivalent charge and similar ionic radii. They can, however, be fractionated from one another as a result of geochemical processes operating under specific physico-chemical conditions. In order to outline general trends within and differences between the individual REE, concentrations are usually normalized to a reference system (e.g. to shale). Deviations of individual elements from the generally smooth trend are referred to as anomalies. 

Trace elements and rare-earth elements (REEs) of the same calcite samples used for the stable isotope analysis have significantly lower concentration of REE as well as most trace elements relative to typical carbonatites. The total REE contents of the Ulsan carbonates range from 3 to 17 ppm, which are much lower than any igneous rocks and even lower than those of some sedimentary rocks. REE and trace-element abundances may have changed sufficiently due to alteration, thus, affecting petrogenetic... 

Rare-earth chlorides, 74 643 Rare-earth elements (REEs)... 

The rare earth elements (REE) are the lanthanides (defined as those elements with valence electrons in 4/orbitals), La, Ce, Pr, Nd, (Pm), Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. Often included for analysis, because they behave in a chemically similar way, although strictly not REE, are the Group 3 transition metals Y and Lu. The radioactive lanthanide element promethium (Pm) is excluded from analysis, since it is not found in samples because of its short half-life. 

Pillay, A. E. and Punyadeera, C. (2001). An enhanced procedure for the rapid digestion of high silicate archeological specimens followed by ICP-MS determination of traces of rare earth elements (REEs). Journal of Trace and Microprobe Techniques 19 225-241. 

Another group of elements attentively investigated for their coordination states in silicate glasses and melts is the rare earth elements (REE). Existing stud-... 

Trace elements also exhibit systematic changes in concentration with depth. Figure 8.37 shows, for instance, concentration profiles of rare earth elements (REE) determined by De Baar et al. (1985) in Pacific and Atlantic waters. Note that the concentration profiles differ for the various elements in the series in particular, the amount of Ce is quite high in surface waters of the Atlantic Ocean. 

Table 10.1 lists r values calculated for normalized distributions of alkalis and alkaline earths between silicates and hydrothermal solutions and for normalized distributions of rare earth elements (REE) between pyroxenes and silicate melts. 

The Rare Earth Elements (REE-Lanthanides and Y) are commonly used to unravel rock-forming processes because of their simiiar chemicai properties, typicaiiy iow soiubiiities and assumed resistance to fractionation in crustai and surface environments. However, under some weathering conditions REE are significantiy mobiiised and fractionated (e.g., Nesbitt 1979 Duddy 1980 Sharma Rajamani 2000). 

Rare earth elements (REEs) displayed an average value of 140 23 ppm for XREEs within the Mn-BIFs (Roberts Prince 1990). REE data displayed a negative Eu anomaly within the Mn-BIF and the barren host rocks DDH 87-2 suggestive of no volcanic input associated with the Mn-BIFs (Fig. 3). Positive Eu anomalies commonly occur with Fe-Mn-bearing sediments associated with igneous systems (Mishra et al. 2007). If low ratios of Cerium and Lanthanum (i.e., Ce/La ratios of < 0.12) occur in... 

Copper, Ni, Re, the rare earth elements (REE), and Tl exhibit similar distributions with the upper quartile of data from samples centred about Pebble West. These elements occur in ponds, springs, and borehole seeps, but are highest in the low-pH ponds. Curiously, elevated values of Cu and REE are not present in borehole seeps (circum-neutral pH). 

Ninety five percent of the phosphorus on Earth belongs to the minerals of the apatite group. Apatites are inorganic constituents of bones and teeth of vertebrate and man, as well as a basis of many pathologic sohd formations. Minerals of the apatite group are the main raw materials in the production of phosphorus fertilizers, fodder and technical phosphates, elementary phosphorus, and phosphor-organic compounds. The mineral is sometimes substantially enriched in rare-earth elements (REE) making their extraction possible (Altshuller 1980). 

Studies of the sorption of natural radionuclides from groundwater have established that minor minerals, such as clays coating the fractures in crystalline rock and Fe- and Mn-oxyhydroxides, are important sinks for radionuclides. For example, investigations carried out at the Aspo facility (Smellie Karlsson 1999) showed qualitatively that rare earth elements (REEs), Sc, Th, U, Ra, and Ba have been scavenged by Fe-oxyhydroxide and calcite precipitates,... 

---