Extraterrestrial iron

Iron(ll) sulfide, FeS, is the mineral troilite, known only to occur naturally in meteoritic (that is, extraterrestrial) iron. On the other hand, pyrite is a very common phase occurring in a wide variety of rocks and is an essential component of the rock type lapis lazuli, from which natural ultramarine (Tazurite) is extracted. Copperas, an important raw material used in the manufacture of synthetic iron oxide red pigments, forms from the breakdown of pyrite. 

The Re- Os method was first applied to extraterrestrial samples in the early 1960s when Hirt et al. (1963) reported a whole-rock isochron for 14 iron meteorites that gave an age of 4 Ga. Further development of this system was hindered by several technical difficulties. Rhenium and osmium each exist in multiple oxidation states and can form a variety of chemical species, so complete digestion of the samples, which is required to chemically separate rhenium and osmium for mass spectrometry, is difficult. In addition, accurate determination of rhenium abundance and osmium isotopic composition requires spiking the samples with isotopically labeled rhenium and osmium, and equilibration of spikes and samples is challenging. A third problem is that osmium and, particularly, rhenium are very difficult to ionize as positive ions for mass spectrometry. These problems were only gradually overcome. 

Pyroxenes from extraterrestrial sources provide unequivocal examples of Ti3+ —> Ti4+ IVCT and Fe2+ —> Ti4+ IVCT bands. For example, the iron-free green titanian pyroxene in the Allende meteorite discussed in 4.4.1 is the one irrefutable example of a mineral showing a Ti3+ — > Ti4+ IVCT transition. The position of the band at 666 nm (15,000 cm-1) shown earlier in fig. 4.2 is insensitive to pressure, but it does intensify at high pressures (Mao and Bell, 1974a), consistent with it representing a Ti3+ —> Ti4+IVCT transition between adjacent Ti3+ and Ti4+ ions located in edge-shared Ml octahedra in the pyroxene structure (fig. 5.13). 

Johnson, K. S. (2001). Iron supply and demand in the upper ocean Is extraterrestrial dust a significant source of bioavailable iron Global Biogeochem. Cycles 15, 61—63. 

The major-element compositions of 200 chondritic IDPs were measured by EDS (Table 1 and Figure 12). All of the particles were identified as extraterrestrial because they have approximately chondritic compositions or consist predominantly of a single mineral grain like forsterite or pyrrhotite (commonly found within chondritic IDPs) 37% of the particles are CSIDPs, 45% are CP IDPs, and 18% IDPs composed predominantly of a single mineral. Table 1 summarizes the compositions of the IDPs. Within a factor of 2 the abundances of oxygen, magnesium, aluminum, sulfur, calcium, chromium, manganese, iron, and nickel are approximately chondritic. CP IDPs are a closer match to Cl carbonaceous chondrites than CS IDPs, and they are closer to Cl bulk than to Cl... 

Olinger CT, Maurette M, Walker RM, Hohenbeig CM (1990) Neon measurements of individual Greeidand sediment particles proof of an extraterrestrial origin. Earth Planet Sci Lett 100 77-93 Olsen E, Davis A, Clarke RS, Schultz L, Weber HW, Clayton R, Mayeda T, Jarosewich E, Sylvester P, Grossman L, Wang MS, Lipschutz ME, Steele IM, Schwade J (1994) Watson—a new link in the HE iron chain. Meteoritics 29 200-213... 

Delaney JS, Dyar MD, Sutton SR, Bajt S (1998) Redox ratios with relevant resolution Solving an old problem by using the synchrotron microXANES probe. Geology 26 139-142 Delaney JS, Jones JH, Sutton SR, Simon S, Grossman L (1999) In situ microanalysis of vanadium, chromium, and iron oxidation states in extraterrestrial samples by synchrotron microXANES (SmX) spectroscopy. Meteorit Planet Sci 34 A32... 

Is the image in Eigure 340 an extraterrestrial landscape, a fluted pie crust, the eye of a chameleon or the work of an abstract artist Incredibly, it is an STM image of a quantum corral formed by moving 48 iron atoms one by one into a... 

The chemical analyses of snow at Base Roi Baudouin (70°S,24°E), Amundsen-Scott Station (90°S), and Plateau Station (79°S,40°E) are listed in Appendix 17.12, based on analyses by Hanappe et al. (1968). The data demonstrate that fim at Base Roi Baudouin on the coast of East Antarctica has higher concentrations of sodium, magnesium, potassium, calcium, manganese, iron, and nickel than fim at South Pole and Plateau stations both of which are about 1,300 km from the nearest coast. The variation of the concentration ratios in Fig. 17.40 suggests that the concentrations of sea salts decrease in the sequence Na (highest). Mg, K, Ca, Fe, and Mn. Nickel does not fit the pattern perhaps because it originates to some extent from extraterrestrial sources. 

Extraterrestrial materials In some extraterrestrial material such as meteorites, elements may show isotopic compositions that are distinct from all terrestrial material investigated. This is related to decay of radionuclides that may already be extinct, due to half-lives which are very short compared with the age of the solar system of 4.6 x 10 years. Such variations are rare for terrestrial materials, in large part due to preferential sampling of the crust, whereas some extraterrestrial material, such as iron meteorites, resemble the Earth s core, in which parent to daughter element ratios may be much higher than in the cmst. 

Ashworth, and Hutchison, 1975 [11] made electron microscopic observations of the hydrous alteration products of olivine in an achondrite and in an ordinary chondrite. Their conclusion was that the Nakhla achondrite, and possibly the Weston chondrite, contain water of extraterrestrial origin which was mobilized by mild shock deformation. Carbonaceous chondrites are believed to be unaltered material left over from the formation of the solar system. They contain substantial amounts of reduced carbon and of water in the form of hydroxyl ions. The oxidation state of iron in some carbonaceous chondrites has been determined by means of Moess-bauer spectroscopy, and it is demonstrated that there is a correlation between the oxidation state of iron and the content of water and reduced carbon in the meteorites (Roy-Poulsen et al., 1981 [284]). 

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