Elements abundance, terrestrial

Order of elemental abundance (terrestrial rocks) 13 th 20th 46th 60th... 

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. 

Schmitt, R. A., and R. H. Smith Research on Elemental Abundances in Meteo-ritic and Terrestrial Matter. General Atomics Report 6642 (1965). 

Generally accepted data for elemental abundances and isotopic compositions are given in Tables 1.2 and 1.3, respectively. The air concentrations in the rightmost column of Table 1.3 are often used as a normalization for observed concentrations in samples. If the atmosphere actually does account for nearly the total terrestrial inventory, then indeed these values are near the average concentration of noble gases in the materials that accreted to from the Earth. Use of these data for normalization does not constitute endorsement of this proposition, however, and whether or not they represent the terrestrial inventory, they are a convenient data set with elemental ratios of air and absolute abundances of the same order of magnitude as many samples. 

Properties of the terrestrial planets that are central to this chapter are summarized in table 10.1 and information about element abundances is contained in Appendix 1. The crustal abundance data for the Earth indicate the presence of relatively high concentrations of Fe, and to a lesser extent Ti, compared to other first-series transition elements. However, the terrestrial abundance of Fe... 

Oxygen comprises approximately 21% of the Earth s atmosphere and nearly 47% of its crust, thus making it the most abundant terrestrial element. By far, the greatest amount of this oxygen is found in combination with silicon and aluminum in the form of complex aluminosilicates that make up the vast proportion of igneous rocks. Smaller amounts... 

At the same time that elemental abundance analyses improved for rock samples, spectroscopic abundance determinations for the solar photosphere advanced. A comparison of elemental abundances in the solar photosphere to Cl chondrites then showed the best agreement for most elements the exceptions being H, C, N, O, and the noble gases. These elements form extremely volatile compounds that may have never accreted to the Cl chondrite parent asteroid or were easily lost from Cl chondrite material while in space or in the terrestrial environment. 

Nitrogen is the most abundant terrestrial element in an uncombined state, as it makes up 78 percent of Earth s atmosphere as N2, but it is a minor component (19 parts per million) of Earth s crust. Nitrogen exists as two isotopes N (99.63% relative abundance) and N (0.4% abundance). Both isotopes are nuclear magnetic resonance (NMR) active, with the rarer N isotope being utilized more commonly in NMR spectroscopy because of its nuclear spin of one-half... 

Figure 2. Relative elemental abundances of the four heavier noble gases in the Martian atmosphere, compared with terrestrial atmosphere and various meteorites, all plotted relative to solar abundances. The atmospheric abundances of C and N are also shown. The Martian atmosphere, like the terrestrial, has a noble gas pattern similar to Cl chondrites, except that the Xe/Kr ratio is much lower, similar to the solar ratio. However, the Martian atmosphere contains approximately two orders of magnitude less noble gas than the terrestrial atmosphere. [Used by permission of Univ. of Arizona Press, from Pepin and Carr (1988), Fig. 1, p. 128.]...

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