Aluminum solar abundance

To illustrate how a (simple) condensation calculation works, let s consider the condensation of corundum (Al203), one of the earliest phases predicted to condense from a solar gas. The partial pressures of aluminum (PAi) and oxygen (P0) in the gas phase must first be determined, based on their solar abundances, over a range of temperatures. The eguilibrium between solid (s) corundum and gas (g) can be represented by this equation ... 

Natural Isotopes of aluminum and their solar abundances... 

Among the elements that make up rocks and minerals, silicon, magnesium, and iron are of almost equal abundance followed by sulfur, aluminum, calcium, sodium, nickel, and chromium. Two of the most common minerals in meteorites and in the terrestrial planets are olivine ((Mg,Fe)2Si04) and pyroxene ((Mg,Fe,Ca)Si03). The composition obtained by averaging these two minerals is very similar to the bulk solar system composition, so it is really no surprise that they are so abundant. 

Aluminum-26 is produced by stellar nucleosynthesis in a wide variety of stellar sites. Its abundance relative to other short-lived nuclides provides information about the stellar source(s) for short-lived nuclides and the environment in which the Sun formed. Aluminum-26 is also produced by interactions between heavier nuclei such as silicon atoms and cosmic rays. Aluminum-26 is one of several nuclides used to estimate the cosmic-ray exposure ages of meteorites as they traveled from their parent asteroids to the solar system. 

Based on the bulk chemistry, IDPs are divided into two groups (i) micrometer-sized chondritic particles and (ii) micrometer-sized nonchondritic particles. A particle is defined as chondritic when magnesium, aluminum, silicon, sulfur, calcium, titanium, chromium, manganese, iron, and nickel occur in relative proportions similar (within a factor of 2) to their solar element abundances, as represented by the Cl carbonaceous chondrite composition (Brownlee et al., 1976). Chondritic IDPs differ significantly in form and texture from the components of known carbonaceous chondrite groups and are highly enriched in carbon relative to the most carbon-rich Cl carbonaceous chondrites (Rietmeijer, 1992 Thomas et al., 1996 Rietmeijer, 1998, 2002). 

The actinides (U, Th, Pu), alkaline earths (Be, Mg, Ca, Sr, Ba), lanthanides (elements La - Lu), Al, and the elements in groups 3b (Sc, Y), 4b (Ti, Zr, Hf), and 5b (V, Nb, Ta) of the periodic table are refractory lithophile elements. The refractory lithophiles are 5% of the total mass of the rock in solar composition material. Aluminum Al, calcium Ca, and titanium Ti are the three most abundant refractory lithophiles, and they form minerals that are the host phases for most of the less abundant refractory lithophile elements such as the actinides, lanthanides, and transition elements in group 5b of the periodic table. Some of the less abundant refractory lithophiles - the group 4b elements Zr, Hf, and the group 3b elements Y and Sc - condense as oxides before any Ca, Al, Ti-bearing minerals form [9], But the rest condense into the more abundant host phases. 

Fig. 2. Gas phase chemistry of aluminum in a solar composition gas as a function of temperature at a total pressure of 10-4 bar. The abundances of the gases are shown as mole fractions...

Probably the most informative objects in meteorites are the refractory, calcium-aluminum-rich inclusions (CAIs). They are sub-millimeter- to centimeter-sized objects found in all types of primitive (chondritic) meteorites. On the basis of their uranium/lead radiometric ages, they are believed to be the first-formed rocks in the Solar System 4). Their chemical compositions are consistent with equilibrium condensation as solids from a gas of solar composition at high temperatures 1700 K). The major mineral phases are spinel (MgAl204), pyroxene (Mg, Ca, Al, Ti silicate), melilite (another Mg, Ca, A1 silicate), and anorthite (CaAl2Si20s). They are enriched in refractory (less volatile) trace elements, such as the rare-earth elements, by a factor of 15-20 (5), reflecting their high temperature of condensation. The abundances of the three stable isotopes of oxygen exhibit a pattern not seen in any terrestrial rocks (6). On earth, ratios of abundances of isotopes, such as and vary by... 

Nonrenewahle resources include the abundant metals (such as iron and aluminum), scarce metals (gold and copper), materials used for energy (fossil fuels and uranium minerals), building materials (limestone, crushed stone, sand, and gravel), and other miscellaneous minerals (halite or natural salt). Running water, wind power, and solar power are not included among materials used for energy because they are renewable sources. 

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