Terrestrial materials

Gr. technetos, artificial) Element 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium. The element was actually discovered by Perrier and Segre in Italy in 1937. It was found in a sample of molybdenum, which was bombarded by deuterons in the Berkeley cyclotron, and which E. Eawrence sent to these investigators. Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial material have been made. Finally in 1962, technetium-99 was isolated and identified in African pitchblende (a uranium rich ore) in extremely minute quantities as a spontaneous fission product of uranium-238 by B.T. Kenna and P.K. Kuroda. If it does exist, the concentration must be very small. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars. 

Extraterrestrial dust particles can be proven to be nonterrestrial by a variety of methods, depending on the particle si2e. Unmelted particles have high helium. He, contents resulting from solar wind implantation. In 10-)J.m particles the concentration approaches l/(cm g) at STP and the He He ratio is close to the solar value. Unmelted particles also often contain preserved tracks of solar cosmic rays that are seen in the electron microscope as randomly oriented linear dislocations in crystals. Eor larger particles other cosmic ray irradiation products such as Mn, Al, and Be can be detected. Most IDPs can be confidently distinguished from terrestrial materials by composition. Typical particles have elemental compositions that match solar abundances for most elements. TypicaUy these have chondritic compositions, and in descending order of abundance are composed of O, Mg, Si, Ee, C, S, Al, Ca, Ni, Na, Cr, Mn, and Ti. 

Economic Aspects. To be useful the raw materials must be recoverable at a cost not greater than the cost of similar terrestrial materials. These costs must include transportation to the point of sale. Comparative costs of recovery are strongly influenced by secondary environmental or imputed costs, such as legal costs or compensatory levies. 

Radon is a noble gas and is therefore not readily ionized or chemically reactive. Its properties in terrestrial material will be controlled by its solubility in melt and fluid as well as its diffusion coefficients. Compared with the lighter noble gases, Rn diffuses more slowly and has a lower solubility in water. It will also more readily adsorb onto surface that the lighter rare gases. It can, however be lost by degassing in magmatic systems (Condomines et al. 2003). More information about the behavior of Rn can be found in Ivanovich and Harmon (1992). 

Lignins and lignin sulfonates are considered to be important tracers of man s activities. The major source of these compounds is the pulp and paper industry lignin is not a marine product, and any large accumulation of these compounds suggests a local dominance of terrestrial materials. 

It is clear from figure 6 that the terrestrial data do not cluster about a single point but instead lie along a line of slope 0.5 on the three-isotope diagram, indicating isotopic variation due to mass-dependent fractionation. Since mass fractionation effects in Mg have not been observed in terrestrial materials [30,31], this distribution of observed isotope ratios must be due to fractionation in the ion probe. The physical process which produces the... 

One interesting side-effect of the industrial isotopic enrichment of Li is the development of isotopically anomalous materials that make their way into other industries. For example, Qi et al. (1997a) formd that commercial shelf standards for Li concentration had compositions that were over 300% enriched in "W relative to known terrestrial materials (Fig. 3). 

The studies by Lee et al. (1977, 1979), Niederer and Papanastassiou (1984), as well those by Jungck et al. (1984), Ireland et al. (1991), Weber et al. (1995) and Russell et al. (1998), report small deviations of the abundances of Ca, Ca and Ca relative to those of terrestrial materials. The most commonly observed deviation from normal terrestrial isotopic abundances is enrichment in Ca, which can be quite large (Fig. 2b). These deviations are significant because they provide direct evidence for the existence of certain (in this case neutron-rich) nucleosynthetic environments in stars (cf Cameron 1979 and references in the other papers listed above). 

The observed range of natural variations of 5 Ca is about 4 to 5%o in terrestrial materials and up to 50%o in high temperature condensate minerals in carbonaceous chondrites. The typical reproducibility of measurements is about +0.15%o. Broader application of Ca isotope measurements in geochemistry may be possible, particularly if the reproducibility can be improved to 0.05%o to 0.03%o. There is hope that this can be achieved either with inductively coupled plasma source mass spectrometry (Halicz et al. 1999) or with a new generation of multi-collector thermal ionization mass spectrometers (Heuser et al. 2002). 

Until only a few years ago, I would never have imagined that a volume on the stable isotope geochemistry of elements like Mg, Fe or Cu would be written. In fact, a comic book of blank pages entitled The Stable Isotope Geochemistry of Fluorine would have been a more likely prospect. In volume 16 of this series, published in 1986, I wrote Isotopic variations have been looked for but not found for heavy elements like Cu, Sn, and Fe.. .. Natural variations in isotopic ratios of terrestrial materials have been reportedfor other light elements like Mg and K, but such variations usually turn out to be laboratory artifacts. I am about ready to eat those words. 

Extraterrestrial materials consist of samples from the Moon, Mars, and a variety of smaller bodies such as asteroids and comets. These planetary samples have been used to deduce the evolution of our solar system. A major difference between extraterrestrial and terrestrial materials is the existence of primordial isotopic heterogeneities in the early solar system. These heterogeneities are not observed on the Earth or on the Moon, because they have become obliterated during high-temperature processes over geologic time. In primitive meteorites, however, components that acquired their isotopic compositions through interaction with constituents of the solar nebula have remained unchanged since that time. 

Thales s successor, Anaximander—the exact dates of his birth and death are unknown, but he was said to have been 64 years old in 546 B.C.—agreed that there was one primal material. But he didn t think it was ever encountered on Earth in its pure state. According to Anaximander everything in the world was made of apeiron, a substance that was infinite and eternal, and which could take on numerous forms, including those of all the familiar terrestrial materials. It is neither water nor any of the so-called elements, Anaximander said, but a nature different from them and infinite, from which arise all the heavens and the worlds within them. ... 

Table 4.2 gives current estimates for the relative abundances of the isotopes in the solar system. The isotopic compositions of most elements, especially those that exist as solids, come from measurements of terrestrial materials. Because the Earth has experienced extensive melting and differentiation, it can be considered a homogeneous isotopic reservoir. However, each of the elements can experience both equilibrium and kinetically based isotopic fractionations during igneous, evaporative, and aqueous processes. The range of compositions introduced by such processes is small for most elements and so does not obscure the overall picture. 

Table 4.2 and similar tables should not be used as the source of isotopic compositions of terrestrial standards for high-precision isotopic measurements. While Table 4.2 gives a good overview of the abundances of the isotopes, the values in the table do not always represent state-of-the-art isotopic measurements. Nor do they attempt to take into account the isotopic fractionations that occur in terrestrial materials. Typically, an isotope system that has been measured for many years has a convention about how isotopic ratios are reported. For example, oxygen isotopic compositions are typically reported relative to the Vienna determination of Standard Mean Ocean Water... 

Range in isotopic composition of normal terrestrial material prevents a more precise value being given the tabulated value should be applicable to any normal material. 

Information on the current arsenic content of the solar system is largely limited to spectrographic analyses of the Sun, Saturn, and Jupiter measurements on available Moon rocks and meteorites and analyses of terrestrial materials. Spectrographic analyses indicate that the arsenic concentration of the Sun is about 0.004 mg kg-1 (Matschullat, 2000, 299 Table 3.1). Arsenic is moderately volatile in the vacuum of space (McDonough, 2004, 555) and should be preferentially concentrated on Jupiter and other planets... 

Liese, H. C., Selected terrestrial minerals and their infrared absorption spectral data 4000 — 300 cm1, in Infrared and Raman spectroscopy of lunar and terrestrial materials (ed. Karr, C.) p. 197, New York, S. Francisco, London, Academic Press 1975... 

There are three principal types of nuclear reactions due to the interactions of terrestrial materials with cosmic rays (i) by high-energy spallation of nucleons (E > 40MeV), principally by neutrons, (ii) by thermal neutron capture, and (iii) muon-induced nuclear disintegrations. Muon reactions become important only at depths below sea level. The estimation of the production ratio is difficult because of lack of knowledge of the probabilities of formation of nuclides in the different reactions. 

In absolute terms, Xe is the least abundant of the noble gases in terrestrial materials (cf. Figure 6.3) precise isotopic analysis is correspondingly relatively difficult... 

Some margins receive their terrestrial inputs from estuarine line-sources (numerous estuaries) with very little direct effects from rivers, while others may receive large direct inputs from rivers, such as deltaic regions these differences will have serious consequences on the amount of terrestrial material recycling that has occurred before entering the coastal zone, as well as how these materials (particulate and dissolved) will be transported offshore. 

Setser, J. L., and W. D. Ehmann Zirconium and hafnium abundances in meteorites, tektites and terrestrial materials. Geochim. cosmochim. Acta 28, 769-782 (1964). 

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