Noble gases argon isotopes

A relative of Henry Cavendish, the duke of Devonshire, donated means which made it possible to establish a laboratory, the Cavendish Laboratory, in 1871. The first holder of the highly esteemed Cavendish professorship was James Clerk Maxwell, the second was Lord Rayleigh, who discovered the noble gas argon in the laboratory. In 1934 the heavy hydrogen isotope tritium was synthesized in the laboratory. 

The atmosphere is a well-mixed reservoir with known concentrations of noble gases (Table 13.1). These atmospheric noble gases have characteristic isotopic abundances that are given in Table 13.2. The solubility of the noble gases is given in Fig. 13.1, expressed in cc STP noble gas/cc water. STP stands for standard temperature (0°C) and pressure (760mmHg=l atmosphere). What is the solubility of argon in distilled water at sea level at 15 °C The answer, from Fig. 13.1, is 3.5 x 10 4cc STP Ar/cc water. 

Recall that fullerenes include spherical C6o carbon molecules ( buckyballs ) whose cavities can trap other atoms such as helium and argon. (See the accompanying figure.) The scientists postulate that the fullerenes originated in the collapsing gas clouds of stars where the noble gas atoms were trapped as the fullerenes formed. These fullerenes were then somehow incorporated into the object that eventually hit the earth. Based on the isotopic compositions, the geochemists estimate that the im-... 

Noble gases and nitrogen in martian meteorites reveal several interior components having isotopic compositions different from those of the atmosphere. Xenon, krypton, and probably argon in the mantle components have solar isotopic compositions, rather than those measured in chondrites. However, ratios of these noble gas abundances are strongly fractionated relative to solar abundances. This decoupling of elemental and isotopic fractionation is not understood. The interior ratio in martian meteorites is similar to chondrites. 

Marty B. and Alle P. (1994) Neon and argon isotopic constraints on Earth-atmosphere evolution. In Noble Gas Geochemistry and Cosmochemistry (ed. J.-l. Matsuda). Terra Scientihc Publishing Company, Tokyo, pp. 191-204. 

The noble gas geochemistry of natural waters, including formation waters in sedimentary basins, has been used to determine paleotemperatures in the recharge areas, to evaluate water washing of hydrocarbons, and to identify mantle-derived volatiles (Pinti and Marty, 2000). The dissolved noble gases, helium, neon, argon, krypton, and xenon in sedimentary waters, have four principal sources the atmosphere, in situ radiogenic production, the deep crust, and the mantle. These sources have characteristic chemical and isotopic compositions (Ozima and Podosek, 1983 Kennedy et al., 1997). 

The name comes from the Greek xenon, meaning stranger. Xenon was discovered by William Ramsay (1852-1916) and Morris W. Travers (1872-1961) in 1898 as part of their search for a noble gas between helium and argon. It is present as a trace element in atmospheric air. It is the heaviest of the noble gases. It is used commercially in specialty lamps and lasers, as well as in sophisticated laboratory equipment such as bubble chambers and as a radioactive isotope used as a tracer. 

The best-known noble gas clathrates are hydrates, hydroquinone and phenol clathrates, which have found an increasing number of uses [131]. Clathrates may serve as convenient storage for noble gases. Because of the different affinity hydroquinone clathrate prepared from an equal mixture of krypton and xenon liberates 3 times the amount of Xe than Kr [132]. Clathrates are also of interest for nuclear technology. Radioactive isotopes of argon, xenon and krypton can more easily be handled in the compact form of a solid rather than in gas form [133-136]. 

Potassium is also famous for one of its isotopes, radioactive potassium-40, which has a long half-life of 1.25 billion years. (Half-life refers to the amount of time it takes for half of the elements atoms to disintegrate.) Potassium-40 occurs naturally and is used by researchers to determine the age of rocks. As potassium-40 decays, it becomes a noble gas called argon. By determining how much argon is present in a rock, researchers can estimate the rock s age. Using this technique, scientists have estimated some rocks on Earth to be as old as 3.8 billion years. 

The noble gases krypton, argon and neon have essentially a similar behaviour as observed for xenon. The growth of the lightest noble gas atom helium with the isotopes He and He is different and behaves more like a fermion gas, as has been extensively discussed by Bj0rnholm [97]. 

Kumagai H, Kaneoka 1 (1998) Variations in noble gas abundances and isotope ratios in a single MORB pillow. Geohys Res Lett 25 3891-3894 Kunz J (1999) Is there solar argon in the Earth s mantle Nature 399 649-650... 

In this section, we review noble gas systematics of arc-related volcanism worldwide. Helium isotope studies dominate because most arc products are erupted subaerially, and air contamination is a relatively minor (correctable) problem for helium this is not the case for Ne-Ar-Kr-Xe isotope systematics. Consequently, this section is weighted towards reporting observations of helium isotope variations in arc-related minerals and fluids. However, we summarize also the available database for neon, argon and xenon isotopes (todateKr shows only air-like isotopic compositions). Finally, we consider the limited database of the relative abundances of the noble gases in arc-related products. 

Martel DJ, Deak J, Dovenyi P, Horvath F, O Nions RK, Oxbmgh ER, Stegna L, State M (1989) Leakage of helium from the Patmonian Basin. Nature 432 908-912 Marti K, Mathew KJ (1998) Noble-gas components in planetary atmospheres and interiors in relation to solar wind and meteorites. Proc Indian Acad Sci (Earth Planet Sci) 107 425-431 Marty B, Alle P (1994) Neon and argon isotopic constraints on Earth-atmosphere evolution. In Noble gas geochemistry and cosmochemistry. Matsuda J-1 (ed) Terra Scientific Publishing Co., Tokyo, p 191-204. 

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