Rare earth elements rock normalization

Figure 2. Rare earth elements concentrations (normalized to chondrites) for the original rocks (serpentinite and hornblende diorite) and their alteration products...

Figure 10.6. Observed secular trends in the chemical composition of sedimentary rocks. Eu/Eu = ratio of observed normalized Eu concentration to that predicted (Eu ) from extrapolation between REE Gd and Sm. REE = rare earth element LREE = light REE HREE = heavy REE. Data from several authors as presented in Veizer (1988).

Rare earth element concentrations in rocks are usi lly normalized to a common reference standard, which most commonly comprises the values for chondritic meteorites. Chondritic meteorites were chosen because they are thought to be relatively unfractionated samples of the solar system dating from, the original nucleosynthesis. However, the concentrations of the RZE in the solar system are very variable because of the different stabilities of the atomic nuclei. REE with even " atomic numbers are more stable (and therefore more abundant) than REE with odd atomic numbers, producing a zig-zag pattern bn a composition-abundance diagram (Figure 4.19). This pattern of abundances is also found in natural samples. 

Vanadium is a rare element, making up only about 0.015% of Earth s crust (by mass). It is a soft white metal with high ductility and malleability, which means that it can be easily drawn into narrow wires or rolled into thin sheets. Because of the high reactivity of pure vanadium, this elanent occurs naturally within compounds (not in its elemental form). However, vanadium compounds are not normally found in the rocks or soils near oil fields, so why does this rare, reactive metal occur in oil The answer lies in the biology of ancient fife-forms. Most modem animals use iron in hemoglobin to transport oxygen through their bloodstreams (see Sections 1.1 and 14.1), and a few (such as lobsters) use copper for this function. It appears that some extinct animals used vanadium. Even today. 

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