Precipitation isotopic composition

Buhay, W. M., 1997. Inferring precipitation isotopic compositions from lake sediment organics and pore water Workshop on water and climate studies in Canada using isotope tracers Past, present, future. University of Waterloo, Waterloo. 

Fig. 18-6 Characteristic air-mass trajectory and corresponding per mil isotopic composition of precipitation, along a transect from the subtropics to a polar ice sheet. This is a highly schematic view of the true atmospheric system.

The global atmospheric circulation acts as an enormous filtration system, which depletes high-latitude precipitation of heavy isotope-bearing water molecules. Because of this system, measurements of the stable isotopic composition of the ice sheets and of ocean-floor sediments reveal very important paleo-environmental information (see Sections 18.2.2,18.3.2, and 18.3.3). Here we examine this filtration system at a physical level. This system was first understood by a great Danish geochemist named Willi Dansgaard (Dansgaard, 1964). 

Fig. 18-23 Observed correlation of isotopic composition of precipitation with ground temperature (gray diamonds Jouzel et ah, 1987), and predictions of simple isotopic models. A, prediction with constant a B, prediction with temperature-dependent a.

Gamo (1995) revealed based on the chemical and isotopic compositions of hydrothermal fluids from midocean ridges that the precipitation of minerals and interaction... 

Isotopic compositions of minerals and fluid inclusions can be used to estimate those of Kuroko ore fluids. Estimated isotopic compositions of Kuroko ore fluids are given in Table 1.10. All these data indicate that the isotopic compositions lie between seawater value and igneous value. For instance, Sr/ Sr of ore fluids responsible for barite and anhydrite precipitations is 0.7069-0.7087, and 0.7082-0.7087, respectively which are between present-day. seawater value (0.7091) and igneous value (0.704-0.705). From these data, Shikazono et al. (1983), Farrell and Holland (1983) and Kusakabe and Chiba (1983) thought that barite and anhydrite precipitated by the mixing of hydrothermal solution with low Sr/ Sr and seawater with high Sr/ Sr. 

Fritz P, Drimmie RJ, Frape SK, O Shea K (1987) The isotopic composition of precipitation and groundwater. In Canada International Symposium on the Use of Isotope Techniques in Water Resources Development. IAEA Symposium, Vienna 299 539-550 Frumkin A, Ford DC, Schwarcz HP (1999) Continental oxygen isotopic record of the last 170,000 years in Jerasalem. (JuatRes 51 317-327... 

Harmon RS, Schwarcz HP, O Neil JR (1979) D/H ratios in speleothem fluid inclusions A grride to variatiorrs in the isotopic compositions of meteoric precipitation Earth Planet Sci Lett 42 254-266 Harmon RS, Thompson P, Schwarcz HP, Ford DC (1975a) Late Pleistocene paleoclimates of North America as irrferred from stable isotope studies of speleothems. Quat Res 9 54-70 Harmon RS, Thompson P, Schwarcz HP, Ford DC (1975b) Uranium-series dating of speleothems. Nat Speleolo cal Soc Bull 37 21-33... 

Water vapor enriched in oxygen-16 is transported by wind in the atmosphere from the sea to land. When the water vapor condenses and precipitates as rain, snow, or hail, the water becomes rich in oxygen-16. Eventually the oxygen-16 rich water is incorporated into rivers, lakes, glaciers, and polar ice, which are, therefore, also rich in oxygen-16. Thus the isotopic composition of groundwater and the water of rivers, lakes, and glaciers is not the same as in seas and oceans. 

Bowen, G. J. and Revenaugh, J. (2003) Interpolating the isotopic composition of modern meteoric precipitation. Water Resources Research 39(10), 1299 Brand, W. A., Tegtmeyer, A. R. and Hilkert, A. (1994) Compound specific isotope analysis extending toward 15N/14N and 180/160. Organic Geochemistry 21, 585 594. 

Long term changes in precipitation, caused by changes in climatic temperature, are well documented in polar ice caps the heavier of the stable isotopes is depleted in ice laid down in the ice age by comparison with present day ice. In 1970 we extended this concept to trees, suggesting that they, also, are thermometers. Trees grow from water and atmospheric C02. In trees which grow on rain water, isotope variations in their rings should be climate indicators because the isotope composition in rain and C02 varies with temperature. 

Geochemical monitoring of chemical and isotopic compositions of CO2 fluids and calcite precipitation during injection tests at Ogachi Hot-Dry Rock site, Japan... 

Analysis for such isotopes as carbon and deuterium has been conventionally used to assess the relative age of groundwater, and in evaluating its origin (i.e., meteoric, juvenile, formation, etc.), chemistry, and total salinity. Isotope composition of ground-water and surface water has also been used to correlate between areas of precipitation and groundwater, thus providing an indication of source area(s) of recharge. 

Figure 12. Extent of dissolution and re-precipitation between aqueous Fe(III) and hematite at 98°C calculated using Fe-enriched tracers. A. Percent Fe exchanged (F values) as calculated for the two enriched- Fe tracer experiments in parts B and C. Large diamonds reflect F values calculated from isotopic compositions of the solution. Small circles reflect F values calculated from isotopic compositions of hematite, which have larger errors due to the relatively small shifts in isotopic composition of the solid (see parts B and C). Curves show third-order rate laws that are fit to the data from the solutions. B. Tracer experiment using Fe-enriched hematite, and isotopically normal Fe(lll). C. Identical experiment as in part B, except that solution Fe(lll) is enriched in Te, and initial hematite had normal isotope compositions. Data from Skulan et al. (2002).

Figure 10. Fe isotope compositions for total aqueous Fe (Fe,(,T) and ferrihydrite (FH) precipitate and aqueous Fe-ferrihydrite fractionations from the batch oxidation and precipitation experiment of Bullen et al. (2001). (A) Measured S Fe values from Bullen et al. (2001), compared to simple Rayleigh fractionation (short-dashed lines, noted with R ) using 10 1naFe.,-FH = 0.9%o, as well as the two-step re-equilibration model discussed in the text (i.e., Eqn. 12), shown in solid gray lines for the aqueous Fe and ferrihydrite components the predicted 5 Fe value for Fe(III), is shown in the heavy dashed line, which reflects continual isotopic equilibrium between Fe(II), and Fe(III),(. Note that in the experiment of Bullen et al. (2001), aqueous Fe existed almost entirely as Fe(II),(,. (B) Measured fractionation between total aqueous Fe and ferrihydrite precipitate, as measured, and as predicted from simple Rayleigh fractionation (black dashed line) and the two-step model where isotopic equilibrium is maintained between aqueous Fe(II),q and Fe(III),q (solid gray line).

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