Large ion lithophile elements,

In summary, a key aspect to the utility of U-series isotopes in the study of arc lavas is that whereas Th and Pa are observed and predicted to behave as relatively immobile high field strength elements (HFSE), Ra and (under oxidizing conditions) U behave like large ion lithophile elements (LILE) and are significantly mobilized in aqueous fluids. Fluid-wedge interaction will only serve to increase these fractionations. Just how robust the experimental partition coefficients are remains to be established by future experiments. 

The incompatibility of certain trace elements with the solid phase results from two factors. First, the large-ion lithophile elements (LILE) such as Ba, Cs, Rb, and Sr have large ionic radii. The LILE are too large for the available ionic sites in the solid and they tend to remain in the liquid phase. A second cause of... 

For example, potassium varied by a factor of almost 10. Various authors found millimeter-sized fragments of this foreign material which represents the second component in the Apollo 12 soil samples28. As the foreign component was rich in potassium, rare earth elements (REE) and phosphorus, the acronym KREEP was devised. Later many other elements were found to be enriched in KREEP, for example, U, Th, Hf, Zr, Nb, and Ta. All these elements have in common large crystal radii (large-ion lithophile elements, LIL elements). The rock type from which the KREEP fragments were derived of is norite. 

Examples of both types are shown in Figs. 13, 14, and 15. Clearly the correlation of MnO with FeO, found in the lunar samples by Laul et al. 100 is due to the fact that Mn++ (R = 0.80 A) can easily replace Fe++ (R = 0.74 A) in the two most abundant Mg, Fe silicates, pyroxene and olivine. The correlation of the LIL elements (large-ion lithophile elements) first observed in KREEP is of the second type. 

Fig. 14. Correlation of large-ion lithophile elements (LIL) following lanthanum in lunar samples. Note that Be (R = 0.35 A) fractionates together with the LIL elements. From Wanke et al.13)...

The melt, containing large fractions of radioelements and other LIL elements from the Moon s interior, will move towards the surface, forming a liquid layer of perhaps 100 km thickness. On cooling, this liquid will differentiate as outlined by Wood85 A solid crust of anorthosite will form on top and will increase in thickness while the denser mafic cumulates will concentrate at the bottom. In the liquid layer between the anorthosite and the mafic cumulates the radioelements, together with all large-ion lithophile elements, will become further enriched. From this layer the KREEP (norite) material is derived. 

Although the rare-earth elements (REEs) have similar geochemical behavior, since they are all large-ion lithophile elements and most of them partition among melts and mineral phases as a smooth function of ionic radius (with the exception of europium, which, commonly being... 

Incompatible elements (rare-earth elements, large-ion lithophile elements, high-field-strength-elements)... 

Rudnick R. L., McLennan S. M., and Taylor S. R. (1985) Large ion lithophile elements in rocks from high-pressure granulite facies terrains. Geochim. Cosmochim. Acta 49, 1645-1655. 

Dalpe C. and Baker D. R. (2000) Experimental investigation of large-ion-lithophile-element-, high-field-strength-element-and rare-earth-element-partitioning between calcic amphi-bole and basaltic melt the effects of pressure and oxygen fugacity. Contrib. Mineral. Petrol. 140, 233-250. 

LILEs Large ion lithophile elements, rubidium, radium, barium, potassium (and caesium— but we do not use caesium data in this chapter). Although they are not, strictly speaking, FILE, we sometimes group thorium and uranium with the FILE when referring to elements that are highly incompatible. 

Normalized incompatible trace element diagrams are shown in Figure 4. The basalts of the Belingwe belt are generally characterized by flat incompatible element patterns (1.7-4,6x primitive mantle) with marked enrichment of Th (28.3x) and Sr (8.2x). The komatiitic basalts show comparable patterns to those of the basalts but with spiked large ion lithophile element... 

Verma SP, Schilling J-G (1982) Galapagos hot spot-spreading center system 2. Sr/ Sr and large ion lithophile element variations (85°W-101°W). J Geophys Res 87 10838-10856... 

Large Ion Lithophile Element Low Field Strength element Million (10 ) years Mid-Ocean Ridge Basalt... 

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