REE patterns in sediments

REE patterns REE concentrations in sedimentary rocks are usually normalized to a sedimentiuy in sediments standard such as NASC, although this practice is not universal and some authors use chondritic normalization. 

Concentrations of rare earth elements In average seawater and average river water normalized to NASC The data are given in Table 4.6, columns 9 and 10. Normalizing values are from Table 4.6 column 5. Note that the concentrations in seawater and river wamr are quoted in mol and must in this case be multiplied by the atomic weight. Concentrations shown are X 10 .  

Diagenesis has little iniluence on the redistribution of the REE, for very large water/rock ratios are required to effect any change in sediment chemistry. 

An important study by Cullers et al. (1987), on the effect of sedimentary sorting on REE concentrations, found that the REE pattern of the source was most faithfully represented in the clay-sized fraction of the sediment. Qay-bearing rocks also have a much higher concentration of total REE than other sediments. It is for this reason that many authors have used the REE content of the clay portion of a sediment or clay-rich sediments in order to publish the sedimentary processes and to identify the provenance. The presence of quartz has a diluting effect on REE concentrations, as does carbonate. The presence of heavy minerals, particularly zircon, monazite and allanite, may have a significant but erratic effect on the REE pattern of an individual sample. 

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