5 NATURAL ABUNDANCE OF THE STABLE ISOTOPES ... - Falw.vu

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Chapter 7for water18 VSMOW (‰)for carbonate18 VPDB (‰)60 40 20 0 +20ocean waterarctic sea icemarine moisture(sub)tropical precipitationDead Sea/Lake Chadtemperate zone precipitationAlpine glaciersGreenland glaciersAntarctic iceQuatern. marine carbonatesfresh-water carbonatesocean watermarine carbonatesigneous rocksmarine atmospheric CO 2atmospheric oxygenorganic matter20 0 +20 +40 +6018 VSMOW (‰)Fig.7.9General view of 18 O/ 16 O variations in natural compounds. The ranges are indicative forthe majority of materials shown. The relation between the VPDB and VSMOW scales isgiven in Sect.7.2.3 and Fig.7.11.Kinetic effects are observed during the evaporation of ocean water, as oceanic vapour isisotopically lighter than would result from equilibrium fractionation alone. The naturalisotope effect for oxygen ( -12‰) is smaller than could be brought about by fractionation bydiffusion. Laboratory measurements resulted in 18 d = -27.3 ± 0.7‰ (Merlivat, 1978) and 18 d= -27.2 ± 0.5‰ (unpubl.). These experimental values are again smaller than results fromEq.(3.35) (-31.3‰), which may be explained by the water molecules forming clusters of104
Stable Isotopes of Hydrogen, Carbon and Oxygenfractionation 18 (‰)5040CO 2 gasg/l30CaCO 3 solids/l20100H 2 O liquid-10H 2 O vapourv/l-200 10 20 30 40temperature t (C)Fig.7.10Temperature dependent equilibrium fractionations for oxygen isotopes of water vapour(v), gaseous CO 2 (g), and solid calcite (s) with respect to liquid water (l).larger mass in the vapour phase. Furthermore, evaporation of ocean water includes sea sprayby which water droplets evaporate completely without fractionation, thus reducing the naturalisotope effect.105
Page 1 and 2: 7 NATURAL ABUNDANCE OF THE STABLEIS
Page 3 and 4: Stable Isotopes of Hydrogen, Carbon
Page 5: Stable Isotopes of Hydrogen, Carbon
Page 8 and 9: Chapter 77.1.3 REPORTING 13 C VARIA
Page 10 and 11: Chapter 7oceanic air far removed fr
Page 12 and 13: Chapter 7Numerically this comes to
Page 14 and 15: Chapter 7-613 (HCO 3 ) (‰)-8Rhin
Page 18 and 19: Chapter 7Table 7.4 Oxygen isotope f
Page 20 and 21: Chapter 7this procedure, the sample
Page 22 and 23: Chapter 7 3 : from 2 , 1 , and 1
Page 24 and 25: Chapter 718 VSMOWocean watertropic
Page 26 and 27: Chapter 7isotope depletion of preci
Page 28 and 29: Chapter 713 VPDB (‰)0lakeevapora
Page 30 and 31: Chapter 77.4.3 REPORTING 2 H VARIAT
Page 32 and 33: Chapter 7Henceforth all 2 values w
Page 34 and 35: Chapter 72 VSMOW (‰)+ 200meteori
Page 36: 124Chapter 7

5 NATURAL ABUNDANCE OF THE STABLE ISOTOPES ... - Falw.vu

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