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As some methods of isotope separation enrich not only heavier isotopes of hydrogen but also heavier isotopes of oxygen when producing heavy water, the concentration of 17 O and 18 O can be measurably higher. Furthermore, the 17 O (n,α) 14 C reaction is a
Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis. Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; these isotopic systems can be used with others, such as strontium or oxygen, to answer questions about population movements and cultural interactions, such as trade.
Oxygen (chemical symbol O) has three naturally occurring isotopes: 16 O, 17 O, and 18 O, where the 16, 17 and 18 refer to the atomic mass.The most abundant is 16 O, with a small percentage of 18 O and an even smaller percentage of 17 O. Oxygen isotope analysis considers only the ratio of 18 O to 16 O present in a sample.
[9] [10] Therefore, SLAP is defined to contain 94.45% the oxygen-18 concentration and 57.2% the deuterium concentration of VSMOW. [9] Using a scale with two defined samples improves comparison of results between laboratories. In December 1996, because of a dwindling supply of VSMOW, the IAEA decided to create a replacement standard, VSMOW2.
Equilibrium isotope fractionation is the partial separation of isotopes between two or more substances in chemical equilibrium. Equilibrium fractionation is strongest at low temperatures, and (along with kinetic isotope effects) forms the basis of the most widely used isotopic paleothermometers (or climate proxies): D/H and 18 O/ 16 O records from ice cores, and 18 O/ 16 O records from calcium ...
Isoscapes of hydrogen and oxygen isotopes of precipitation, [4] [5] surface water, [6] groundwater, [7] [8] and tap water [9] have been developed to better understand the water cycle at regional to global scales.
[19] [70] [d] Earth is unusual among the planets of the Solar System in having such a high concentration of oxygen gas in its atmosphere: Mars (with 0.1% O 2 by volume) and Venus have much less. The O 2 surrounding those planets is produced solely by the action of ultraviolet radiation on oxygen-containing molecules such as carbon dioxide.
One useful isotope for reconstructing past climates is oxygen-18. It is another stable isotope of oxygen along with oxygen-16, and its incorporation into water and carbon dioxide/carbonate molecules is strongly temperature dependent. Higher temperature implies more incorporation of oxygen-18, and vice versa.