Oxygen & Hydrogen: Ideal, double isotopic tracer system 18

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1 NATURAL WATERS xygen & ydrogen: Ideal, double isotopic tracer system 18, D, T Conservative tracers Intrinsic to the molecule δd vs. δ 18 plot Utility to ydrology: rigin and Age of Water Tracing of Water, Ions and Contaminants Paleotemperatures Elucidate Physical Processes

2 YDRGEN ISTPES Protium at. % Deuterium at. % Tritium :10 18 alf life 1.3 yr

3 XYGEN ISTPES p+8n 8p+9n 8p+10n xygen at. % xygen at. % xygen at. %

4 ELEMENT ISTPE ATMIC WEIGT amu ABUNDANCE atom % YDRGEN z = Protium Deuterium Tritium ~10-16 (T 1/ =1.6 a) CARBN z = C C C ~10-10 (T 1/ = 5730 a) XYGEN z =

5 Isotopic Molecules & Material Balance What causes isotopes to vary in abundance, or "fractionate"? is a mixture of 9 isotopic species = isotopologues 16 D 16 DD D 17 DD D 18 DD 18 Properties of these molecules are not identical. Thermodynamic differences exist between species.

6 STABLE ISTPLGUES F WATER amu Ab= 997,300 ppm P =3.756 torr amu Ab=400 ppm P =3.645 torr amu Ab=,000 ppm P =3.535 torr amu Ab=300 ppm P =.01 torr amu Ab=.1 ppm amu Ab= 0.6 ppm amu Ab= 0.0 ppm P =0.54 torr amu Ab=10-5 ppm.074 amu Ab.=5*10-5 ppm Criss & Farquharr 008

7 PRPERTIES F RDINARY AND EAVY WATER PRPERTY D Molar Mass C kcal/mole Vapor 5 C torr Melting Point C Boiling Point C Critical Temperature C 5 C C millipoise Disassociation Const. 1.0 x x Latent eat of Fusion C 1515± C Toxicity None Poisonous

8 Isotopic Ratio: R = D/ 13 C/ 1 C 18 / 16 etc. Delta Values:! =1000 R x! R std R std "D = 1000 ( D/ ) x # ( D/ ) std ( D/ ) std " 18 = 1000 ( 18 / 16 ) # 18 / 16 x ( 18 / 16 ) std ( ) std Isotopic Fractionation Factor " A#B = R A /R B = $A $B

9 Table.3: Selected Isotopic Fractionation Factors Form: eq 1000 ln! A B = c c /T c 3 /T Type Phase A Phase B C1 C C3 T K range D/ Water Water vapor to 373 K 1 13 C/ 1 C C3 - C(g) to C/ 1 C Calcite C(g) to / 16 C(g) Water to / 16 Calcite Water to / 16 Quartz Magnetite to S/ 3 S Sphalerite Galena to Ref References: 1) Majoube, 1971; ) Merlivat and Nief, 1967; 3) Majoube, 1970

10 Table.3: Selected Isotopic Fractionation Factors Form: eq 1000 ln! A B = c c /T c 3 /T Type Phase A Phase B C1 C C3 T K range D/ Water Water vapor to 373 K 1 D/ Water Water vapor to 73 K 18 / 16 Water Water vapor to 373 K 1 D/ Ice Water vapor to 73 K 18 / 16 Ice Water vapor to 73 K 3 Ref References: 1) Majoube, 1971; ) Merlivat & Nief, 1967; 3) Majoube, 1970

11 Water-Water Vapor Majoube 1.008! D ! D! 18 extrapolated ! Merlivat 1 C.. C.P T C

12 Material Balance Relationships Bulk isotope ratio of a multi-component system: R system = n! N j * j = 1 n! N j j= 1

13 R system = n! N j * j = 1 n = N 1 * + N * * N n n N j! N j j = 1! j= 1 R system = N 1 n! N j j = 1 N 1 * N + N n 1!j= 1 N j N * N +... n R =! X system j R j j = 1 where the Xj are the mole fractions of the reference nuclide of interest, such that: n! j= 1 X j = 1

14 Simple Binary Mixing R 100:1 R 10:1 5:1 :1 (R 1 +R )/ 1:1 1: 1:5 1:10 R X 1:100

15 YDRSPERE 1.36 x 10 9 km 3 = 1.36 x 10 1 liters Seawater 97. % 3.5 wt % salt; very homogeneous covers 70% of the surface, mean depth 3.8 km Icecaps & Glaciers.15 % >75% of fresh water Pleistocene oscillations ± 100 m Groundwater 0.6 % % of all fresh water Lakes, inland seas 0.017% Atmosphere 0.001%! Stream Channels %

16 YDRSPERE 1.36 x 10 9 km 3 = 1.36 x 10 1 liters Seawater 97. % 3.5 wt % salt; very homogeneous covers 70% of the surface, mean depth 3.8 km Icecaps & Glaciers.15 % >75% of fresh water Pleistocene oscillations ± 100 m Groundwater 0.6 % % of all fresh water Lakes, inland seas 0.017% Atmosphere 0.001%! Stream Channels % USGS

17 Typical Values RESERVIR VLUME %!D! 18 cean ± 5 0 ± 1 Icecaps & Glaciers ± ±15 Groundwater 0.6 Vadose Water -40 ± 70-5 ±15 Dilute Groundwater -50 ± 60-8 ±7 Brines -75 ± 50 0 ±4 Surface Waters Freshwater Lakes -50 ± 60-8 ±7 Saline Lakes & Inland Seas -40 ± 60 -± 5 River & Stream Channels -50 ± 60-8 ±7 Atmospheric Water ± 80-0 ±10 Criss 1999

18 CEAN: 97. % of hydrosphere Mean depth ~ 3.8 km Volume = 1.37 x 10 9 km 3 SEAWATER: Very uniform, buffered Salinity 35 δ 18 = 0 ± 1 δd = 0 ± 5 Isotopic variations coupled with salinity variations E/P, sea ice Melt icecaps: δ 18 ~ -1 Sr, S Temporal Variations

19 E-W ~0 N Craig & Gordon 1965

20 Craig & Gordon 1965

21 ! ATLANTIC SURFACE WATERS Craig & Gordon 1965 Epstein & MAyeda a 1953 NADW ff Maine Greenland, E. Coast North Atlantic ff Bermuda NADW ff Greenland Salinity

22 METERIC WATER Water that originates as precipitation in the hydrologic cycle Large isotopic variations: Values lowest in cold, high latitude, interior regions Approx Range: δ 18 = +4 to -6 δd = +40 to -500 e.g., SLAP (-55.5, -48)

23 δ 18 values of Meteoric Waters modified after Taylor 1974

24 Water Types: METERIC WATER: riginates as precipitation w/i hydrologic cycle Large variations: δ 18 = +4 to -6 δd = +40 to -500 Meteoric Water Line (MWL) δd = 8 δ Slope: equilibrium effect y-intercept: kinetic effect Deuterium excess = δd - 8 δ 18 Some Local Variation Different water lines Intercept can be higher in low humidity regions, e.g., + for Mediterranean

25 SMW δd δd = 8 δ δ 18 Craig 1961

26 0-100!D = 8! SMW!D SLAP ! 18

27 -30 May MERAMEC!D MISSISSIPPI MISSURI ! 18 Criss (1999)

28 0 Ladue, Missouri -5! YEAR 5 0 Seimonthly Precipitation, Inches Criss

29 SMW δd => Evolved Waters δ 18 Craig 1961

Environmental Isotopes in Hydrology. Woocay substituting for Walton

Environmental Isotopes in Hydrology Oct 7, 2010 1 What is an Isotope? An element is defined by the number of protons (Z) in the nucleus The number of neutrons (N) defines the isotope(s) of that element