REE patterns

J SC normil- it has observed that the concentradon of many elements in fine-grained ization for rocks in condnental platforms around die world is similar as a 

Rock Less commonly some authors normalize REE concentradons to a pardcular sample 

The REE are regarded as amongst the least soluble trace elements and are relatively immobile during low-grade metamorphisra, weathering and hydrothermal alteration. Michard (1989), for example, shows that hydrothermal solutions have between 5 X 10 and 10 times less REE than the reservoir rock through which they have passed and therefore hydrothermal activity is not expected to have a major effect on 

---

Figure 1.46. REE patterns of the altered volcanogenic rocks and Kuroko ores. Data sources Shikazono (1999a). (A) Hydrothermally altered dacite and anhydrite underlying the Kuroko ores. (B) Barite, Kuroko ore and ferruginous chert. (C) Hydrothermally altered basalt overlying the Kuroko ores (Shikazono, 1999a).

The REE pattern for fresh volcanic rocks in the Kuroko mine area studied by Dudas et al. (1983) is shown in Fig. 1.47 which shows no negative Ce and no positive Eu anomalies and FREE (Light Rare Earth Element) are not enriched compared with HREE... 

The REE pattern for anhydrite is different from that of seawater, indicating that anhydrite did not precipitate due to the simple heating of seawater that was suggested by Sakai et al. (1970) and Sato (1973). This REE pattern could be explained in terms of the mixing of hydrothermal solution and cold seawater and low degree of seawater/hydrothermal solution mixing ratio (Shikazono et al., 1983). 

REE pattern normalized by NASC (REE contents Goldstein and Jacobsen, 1988) are shown in Fig. 1.156. 

The REE pattern for the Nishikurosawa exhibits slightly light REE enriched one (La/Yb = 0.55 0.09) and plots elose to the line of NASC normalized value = 1. Positive Ce anomaly is also found in the Nishikurosawa. This anomaly is defined by the following equation. 

A few REE data on hydrothermal solutions are available (Fig. 2.34). Chondrite normalized REE patterns of hydrothermal solutions from Vienna Wood, Pacmanus and Desmos, Manus Basin exhibit positive Eu anomaly and LREE enrichment are similar to midoceanic ridge solution and Kuroko ore fluids. This positive Eu anomaly (Fig. 2.35) may have been caused by the selective leaking of Eu due to the interaction of an ascending hydrothermal solution and footwall volcanic rocks (Gena et al., 2001). It is interesting to note that altered basaltic andesite has a negative Eu anomaly and this feature is the same as that found in the Kuroko mine area (Shikazono, 1999). 

Figure 2 shows REE patterns for a selection of rivers showing positive anthropogenic Gd anomalies. These anomalies are found across the world in Japan, Australia, Europe and the U.S., in areas of high population density. The anthropogenic Gd in river waters can be related to the use of Gd compounds as contrast agents in MRI (Bau Dulski, 1996). Availability of modem medical facilities, therefore, is a prerequisite for producing such Gd anomalies. This is shown by the lack of a positive Gd... 

Chondrite-normalized REE patterns were based on values by Evensen et al. (1978) averaging the samples firstly determined in ppm for each site. 

Figure 8.38 Ce anomalies in normalized REE patterns of seawater at various depths. Reproduced with modifications from H. J. W. DeBaar, M. R Bacon, P. G. Brewer, and K. W. Bruland, Geochimica et Cosmochimica Acta, 49, 1943-1960, copyright 1985, with kind permission from Elsevier Science Ltd., The Boulevard, Langford Lane, Kidlington 0X5 1GB, UK.

Figure 8.38 shows that the anomalous concentration of Ce results in a positive Ce anomaly in normalized REE patterns (relative abundances arranged in order of increasing atomic number). This anomaly, which may be ascribed to scavenging by Mn-Fe hydroxides, decreases progressively and inverts with depth. 

Chondrite-normalized REE patterns show that all types of dykes are depleted in HREE relative to LREE (Fig. 5). Also dykes display high SrA (ave. 86 ppm) and La/ Yb (up to 80 ppm) ratios. 

Fig. 5. Cl chondrite-normalized REE patterns showing the low HREE relative to LREE, suggesting a garnet-bearing and plagioclase-free source, as well as an adakitic-geochemical composition.

Selandian Rb-Sr ages of 59.6 2.8 Ma and 60.3 0.8 Ma were determined for the K1A and K19 bodies, respectively these bodies occur in the southwestern part of the field and are either barren of diamond or have the poorest diamond results within this field (Hood McCandless 2004 Fig 1). Mineralogical (e.g., amphibole, sanidine) and geochemical evidence (e.g., flatter chondrite-normalized REE pattern versus the steep profile of typical kimberlite) enticed Eccles et al. (2008) to conclude that these rocks are better referred to as hybrid kimberlite-ultrabasic rocks. 

The oldest profile (CBAC 215) was preserved beneath Paleocene lake sediments. The least weathered saprock in this profile (59 m beneath the unconformity) has a REE pattern very similar to North American shale composite (NASC). The light REE show marked relative depletion in the upper part of the profile and enrichment near the weathering front. Cerium shows marked enrichment at depth (Fig. 2). 

A third profile (BRAC 1) was examined beneath Late Miocene alluvial sands and ferruginous gravels. This profile is considered to be mid Cenozoic in age and has been partly eroded. The upper part of this profile below the unconformity has a similar REE pattern to NASC. Deeper in the profile there is relative enrichment in all the REE, but slightly more marked in the light REE (Fig. 4). 

Fig. 3. REE pattern in Miocene profiie preserved beneath ieucitite iava flow at Wiiga Tank. S is saproiite.

Fig. 4. REE pattern in a partiy eroded mid Cenozoic weathering profiie beneath Late Miocene aiiuviai sediments. S is saproiite.

REE patterns in weathered siliclastic metasedimentary rocks in the Cobar region vary depending on the stage and conditions of weathering. 

Fig. 5. REE pattern in a post Miocene weathering profile. S is saprock/saprock, R fresh rock.

Fig. 3. Chondrite-normalized mean REE patterns of different generations of uranium oxides from the Millennium (square) and Eagle Point (triangle) deposits with their corresponding U-Pb isotopic age.

The uranium oxides from the Eagle Point and Millennium deposits have bellshaped REE patterns centred on Tb or Dy, typical of unconformity-related deposits (Pagel et al. 1987 Fayek ... 

The chondrite-normalized REE patterns for basement-hosted uranium oxides are similar, except for a small variation of LREE abundances, indicating identical physico-chemical deposition conditions (T, pH, fluid composition) for the Eastern part of the Athabasca Basin basement. The previous REE distinction made between Ingress and Egress deposits (Fayek Kyser 1997) is not confirmed by the present study, because both types have similar REE abundance and fractionations, indicating the similarity of the sources and the processes for both deposit types. Thus, these results suggest... 

Keywords cage, marble, skarnoid, primary skarn, REE pattern... 

REE patterns of the uranium oxides present a decreasing fractionation from the iight to the heavy REE, with no or a... 

REE patterns of Th-rich uraninite and uranothorianite, are characterized by the high REE contents, a weak global fractionation, and a marked negative Eu anomaly (Fig.2), that are typical for magmatic uraninite, in particular those of the Rbssing alaskite (Bonhoure 2007). 

In marbles and skarnoids, the consistent U-Ba-Mo-Pb-V-Zn association and absence of Th, the rare occurence of graphite, and the REE patterns in uraninite are evidences for a possible synsedimentary and/or diagenetic origin of the uranium and associated metals. This primary metal stock located in impure dolostone with possible evaporitic layers (as indicated by the presence of scapolite and kampfite in skarnoids) would have been more or less remoblllzed during regional metamorphism and tectonics. 

A late-metamorphic origin is proposed for the U-Th mineralization because of its spatial association with late pegmatites, its high contents in Th, REE, and Y contents and the typical magmatic REE patterns of the U minerals. 

Steinmann, M. Stille, P. 1998. Strongly fractionated REE patterns in salts and their implications for REE migration in chloride-rich brines at elevated temperatures and pressures. Comptes Rendus Academie des Sciences, Paris, II, 327, 173-180. 

In order to trace the migration of basalt-derived REE in the salt, REE distribution patterns (Fig. 7) and Nd isotopic compositions (Fig. 8) have been determined in a salt horizon adjacent to a basalt dyke (Fig. 2). The flat REE distribution patterns and the almost basaltic Nd isotopic composition of the salt samples collected at the basalt-salt contact point to a basaltic origin of the REE for this sample. With increasing distance from the contact, the patterns are more and more depleted in Ce, Pr, Nd, Sm, and Eu and the Nd isotopic compositions are slightly shifted towards lower eNd values, which, however, still remain above values typical for continental crust or Permian seawater (Stille et al. 1996, and citations therein). This evolution of the REE distribution patterns and the Nd isotopic compositions could basically be due to mixing between a basalt and a salt end member or, alternatively, it could have been fractionation of the REE during migration in the salt that modified the REE patterns. 

Afterwards, the percentage calculated in equation (1) has been used together with the REE patterns of the two end members to calculate a hypothetical REE mixing pattern for each of the three intermediate samples according to equation (2) ... 

Rare earth element patterns for basalt and chondrite, and the chondrite-normalized basalt REE pattern. Normalization removes the zigzag pattern due to differences in odd and even atomic number abundances. The europium (Eu) anomaly in the normalized pattern is due to incorporation of extra plagiodase. 

---