Trace elements abundance patterns

The applications of activation analysis are almost innumerable. In the physical sciences, activation analysis is used in trace-element analysis of semiconductor materials, metals, meteorites, lunar samples, and terrestrial rocks. In most cases, the multielemental analysis feature of activation analysis is used to measure the concentrations of several trace-elements simultaneously. From these detailed studies of trace-element abundance patterns, one has been able to deduce information about the thermal and chemical history of the Earth, moon, Mars, and meteorites, as well as the source or age of an object. 

The bulk trace element abundance patterns in CAIs are generally agreed to reflect element volatility, with the most refractory elements enriched relative to solar (Cl chondrite) abundances, and volatile elements depleted. 

Trace-element abundance patterns, often called spidergrams, of MORE are shown in Figure 11 ( spidergram is a somewhat inappropriate but a convenient term coined by R. N. Thompson (Thompson et al., 1984), presumably because of a perceived resemblance of these patterns to spider webs, although the resemblance is tenuous at best). The data chosen for this plot are taken from le Roux et al. (2002) for MORE glasses from the MAR (40-55° S), which encompasses... 

Figure 18 Primitive mantle normalized trace-element abundance patterns for whole-rock MARID xenoliths from kimberlites. Primitive mantle values used for normalisation in this plot and subsequent plots are those of McDonough and Sun (1995) (sources Pearson and Nowell, 2002 Gregoire et al, 2002).

Trace element abundances of rocks dredged from the Sicily Channel seamounts are scarce (Beccaluva et al. 1981 Calanchi et al. 1989). They show variable concentrations, with incompatible element abundances increasing from tholeiitic to alkaline basalts and basanites (Fig. 8.17). Mantle normalised incompatible elements define bell-shaped patterns (not shown), which resemble those for the exposed rocks in the Sicily Channel. 

Patterns of Elemental Distribution. The major, minor, and trace element abundances and the lithology of the stratigraphic sequence are summarized in Tables I and II for the Beulah coals. The data from the Center Mine is given in Karner and others ( 1) where the spatial distribution of elements in the seam was described as fitting into several patterns. In this study the classification of elemental distribution patterns includes 1) Concentration at... 

The presence of Cl, Br, S, and Si can be deduced from the unusual isotopic abundance patterns of these elements. These elements can be traced through the positively charged fragments until the pattern disappears or changes due to the loss of one of these atoms to a neutral fragment. 

Table 3 summarizes the results of an analysis of four extremely helium-rich luminous sdOs (Husfeld, 1986 Husfeld et al., in preparation). Here, only upper limits for the hydrogen abundances can be given as no traces of this element can be found in the spectra. Consequently, helium appears as the most abundant element. Significantly overabundant are also carbon (with one exception LSE 263) and nitrogen. Silicon is effectively unaltered. This abundance pattern compares well with the abundances found in the extreme helium stars of spectral type B (given in col. 6 of Table 3). However, it should be stressed that the carbon depletion in LSE 263 makes this star a peculiar object in its class.

Major and trace element variations for the Lipari rocks show scattering and a bimodal distribution of compositions (Fig. 7.9). However, detailed studies highlighted distinct trends for several trace elements, especially Zr vs. Sr (see Crisci et al. 1991). Rhyolites display variable abundances for several trace elements such as Zr, Th, and Rb. REE of mafic rocks are fractionated and have flat HREE patterns silicic rocks contain strong negative Eu anomalies (Fig. 7.10a). Incompatible element patterns of mafic rocks are fractionated with negative anomalies of HFSE and positive spikes of Sr and Pb (Fig. 7.10b). 

Trace elements concentrations have been measured in 10 AOAs from Allende (Grossman et al, 1979). Most AOAs have unfractionated abundances of refractory lithophile and side-rophile elements (2-20 X Cl) two AOAs analyzed have group II REE patterns. 

A clast from Mount Padbury has a mg of 36, a molar FeO/MnO of 36, and a flat REE pattern at 9-10 X Cl chondrite abundances (Mittlefehldt, 1979)—all within the ranges for basaltic eucrites. However, many basaltic clasts are distinct in major element composition, with higher mg s and lower molar FeO/MnO ratios than those of basaltic eucrites, and have LREE-depleted patterns and (Eu/Sm)ci > 1— patterns unknown among unaltered basaltic eucrites. Some gabbro clasts are similar to cumulate eucrites in major-and trace-element contents, but many are distinct in having extreme depletions in the most incompatible elements (Mittlefehldt, 1979 Rubin and Mittlefehldt, 1992). In extreme cases, samarium abundances are only 0.02-0.03 X Cl chondrites (Rubin and Jerde, 1987 Rubin and Mittlefehldt, 1992), much less than the 1-2 X Cl typical of cumulate eucrites. These clasts have (Eu/Sm)ci of 220-260, the most extreme ratios known among solar system igneous rocks (Mittlefehldt et al., 1992). 

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