Hydrogen lithosphere

The elements whose isotopes are routinely measured with gas inlet mass spectrometers are carbon (12C and 13C, but not 14C), oxygen (160, 170, l80), hydrogen ( H, 2H, but not 3H), nitrogen (14N and 1SN) and sulphur (32S, 33S, 34). Stable isotopes of H, C, N, O, and S occur naturally throughout atmosphere, hydrosphere, lithosphere, and biosphere. They are atoms of the same elements with a different mass. Each element has a dominant light isotope with the nominal atomic weight (I2C, 160,14N, 32S, and H) and one or two heavy isotopes (l3C, nO, 180, 15N, 33S, 34S, and, 2H) with a natural abundance of a few percent or less Table 1). 

Ion microprobe analyses of hydrous minerals in Martian meteorites reveal two different sources of hydrogen. One is interpreted as magmatic water, with 5D = 900 permil, and thought to reflect the mantle composition the other is thought to reflect the atmospheric composition, with 5D =4000 permil (Leshin, 2000). The incorporation of atmospheric water into these meteorites suggests some kind of cycling of water between the atmosphere and lithosphere on Mars. 

Of the iron meteorites 99.22% of the material is made up of even nmn-bered elements, and of the stone meteorites, 97.50%. While the results for the earth s litho here are not so striking, they still show the same general tendency very strongly for, of the six most abundant elements, only aluminum is odd numbered, and the elements of even atomic number make up about 86% of the material. The only odd numbered elements other than hydrogen present in the lithosphere in amounts over 0.2% are aluminum, sodium, and potassium. 

Apart from the small values for hydrogen and helium, the Earth s composition is not remarkable, the percentages by weight of the commonest elements, taking hydrosphere and lithosphere together, are ... 

Earth s crnst is 0.87% hydrogen by mass. The lithosphere is only 0.15% hydrogen. Account for this difference. 

Of approximately 80 elements found in soils, 17 are used by plants to grow. These are called the essential elements and include H, C, O, N, P, S, K, Mg, Ca, B, Cl, Mn, Fe, Cu, Zn, Mo, and Co. Hydrogen and O are derived from the hydrosphere, C from the atmosphere, N from the biosphere, and the remaining 13 from the lithosphere or the mineral soil. Soil is mainly an O-Si-Al-Fe matrix containing relatively small amounts of the other essential... 

On Earth, elements maybe found in the lithosphere (the rocky, solid part of Earth), the hydrosphere (the aqueous, or watery, part of Earth), or the atmosphere. Elements such as the noble gases, the rare earths, and commercially valuable metals like silver and gold occur in only trace quantities. Others, like oxygen, silicon, aluminum, iron, calcium, sodium, hydrogen, sulfur, and carbon are abundant. 

Sodium occurs widely as NaCl in seawater and as deposits of halite in dried up lakes etc. (2.6% of the lithosphere). The element is obtained commercially by electrolysis of NaCl melts in which the melting point is reduced by the addition of calcium chloride sodium is produced at the iron cathode (the Downs cell). The metal is extremely reactive. It reacts vigorously with the halogens, and also with water to give hydrogen and sodium hydroxide. The chemistry of sodium is very similar to that of the other members of group 1. 

Water was surely abundant in early atmospheres and throughout Earth s history with a cooled lithosphere. If there were water. Earth had an oxidizing atmosphere, while hydrogen liberated from water escaped from Earth s atmosphere just as it continues to do today. Both hydrogen gas and helium, when released into Earth s atmosphere, escape from Earth never to return, because the thermal velocity of these gases is above the escape velocity of a mass of their size. They are two of a very few substances that are not automatically recycled. We have no other choice than to recycle unless garbage is to be disposed of in outer space, a highly unlikely event. 

THE LIGHT STABLE isotopes of hydrogen, carbon, nitrogen, oxygen, and sulfur (HCNOS) are natural tracers of geologic/planetary processes. These elements and their isotopes are major constituents of common compounds that are foimd in gas, liquid, and solid form. As such, they make excellent tracers of interactions between major reservoirs such as the atmosphere, hydrosphere, lithosphere, and asthenosphere of a planetary bo(. Their isotopic ratios are readily measured by mass spectrometric methods. 

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