O-H_Stable_Isotopes

Effected by temperature and wr in essence we see 18o

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Unformatted text preview: eas rocks have higher δ18O and δD values. • With increased water-rock interaction (i.e., more hydrothermal alteration), the altered rock becomes isotopically lighter due to exchange reactions between the fluid and the rock. • • Effected by temperature and W/R. In essence, we see δ18O and δD depletions in rocks altered by high temperature fluid-rock interaction. Wednesday, 15 August, 12 Theoretical Closed System Natural Open System Natural Closed System Theoretical Open System from Ohmoto 1986 Wednesday, 15 August, 12 Fluid: Rock Ratios Equations to Quantify Water:Rock Interaction 18 W / Rclosed W / Ropen δO = 18 δO final rock initial fluid 18 initial rock 18 final fluid −δ O −δ O ! final initial & δ 18 Orock − δ 18 Orock # = ln $ 18 initial + 1! = ln[W / Rclosed + 1] ! 18 final $ δ O fluid − δ O fluid ! % " W/R = water/rock ratio δ18Orock,initial, δ18Orock,final = initial and final rock δ18Ofluid,initial, δ18Ofluid,final = initial and final fluid adapted from Taylor 1979, 1997 Wednesday, 15 August, 12 From Huston (1999) Wednesday, 15 August, 12 Fluid:Rock Ratio from Rollinson (1993) Wednesday, 15 August, 12 from Rollinson (1993) Rock Fluid Wednesday, 15 August, 12 δ18O in Fukazawa VMS District m δ18O Black = ore, Stipple: dacite intrusives from Taylor 1997 as adapted from Green et al. 1983 Wednesday, 15 August, 12 Noranda VMS Camp Gibson and Galley (2007) Wednesday, 15 August, 12 Noranda VMS Camp Gibson and Galley (2007) Wednesday, 15 August, 12 δ18O in Noranda VMS District ~700 analyses fro...
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