Europium anomaly negative

Chondrite-normalized REE profiles (Fig. 1) for massive sulfides exhibit a prominent enrichment in LREE and Eu. The enrichment of LREE over the HREE is substantiated by strong positive REE correlations with La, Ce, Pr, Nd and Sm, and a (La/Lu)N ranging widely from 0.15 to 387. Europium anomalies are distinctly positive with (Eu/Eu )n averaging 4.7, but vary widely, ranging from 0.21 to 36. Minor negative Eu anomalies occur in semi-massive sulfides, due to dilution by volcaniclastic material. A positive... 

One of the most striking findings during the analyses of the first lunar samples was the large negative europium anomaly found in all mare basalts29-31) and later in the KREEP samples, too (Fig. 10). 

NWA Oil is basaltic in composition, with enrichments in aluminum, calcium, and titanium relative to chondrites, and is ferroan, with an mg of 36. NWA 011 has a cumulate-eucrite-like REE pattern (Figure 6). However, Afanasiev et al. (2000) report that NWA Oil has a negative europium anomaly and samarium content of 13.3 X Cl, more like those expected for a mafic melt composition. Yamaguchi et al. (2002) suggest that the heterogeneous distribution of calcium phosphate is the likely explanation for this discrepancy. This is supported by their hafnium and tantalum analyses, which are at 12.8 X Cl and... 

Figure 15). Conversely, the most REE-enriched sample from the Garret Transform shows a negative europium anomaly that might result from the entrapment of melt evolved after plagioclase fractionation. However, further assessment of this hypothesis is hampered by secondary alteration (Niu and Hekinian, 1997a).

As a result of these factors, the REE pattern of seawater is distinctive. The seawater pattern is heavy REE enriched (e.g., Elderfield and Greaves, 1982). In addition, cerium shows a marked depletion compared with its neighbors, lanthanum and praseodymium. Because average shale contains a negative europium anomaly compared to chondrites, the practice of normalizing seawater to... 

The negative Eu anomaly implied by the data of Table 6 is small ( 10-20%) but is miiy defined for the f02 region near QFM. As fo2 decreases to near IW, the negative europium anomaly will also increase. At lunar oxygen fugacities the... 

Because europium is commonly fractionated from the other lanthanides, the relative enrichment or depletion (commonly referred to as positive and negative Eu anomalies, respectively) has been quantified as the term Eu/Eu. Eu is the theoretical value for no anomaly (i.e. a smooth lanthanide pattern between Sm and Gd) and is calculated on that assumption. Thus ... 

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