U–Sr isotopic speedometer: Fluid flow and chemical weathering rates in aquifers

Recharge Data Package for Hanford Single-Shell Tank Waste Management Areas

“…The chloride-derived estimated recharge rate of 3.91 mm/yr for borehole 299-W22-48 is consistent with the estimates of 7 ± 3 mm/yr by Maher et al (2003) and 5 ± 2 mm/yr by Maher et al (2006) using strontium and uranium isotope analyses on samples from the same borehole. In contrast, the estimated recharge rate is considerably less than the 35 to 60 mm/yr recharge estimated by DePaolo et al (2004) using isotopic analysis of oxygen from 299-W22-48 samples.…”

“…These are consistent with our expectation for graveled surfaces, but we felt that the newness of the application to Hanford required more consideration before acceptance. Maher et al (2006) used a methodology that employed natural isotopic ratios of strontium and uranium and estimated a rate of 5 ± 2 mm/yr. This estimate is applicable to recharge hundreds to thousands of years ago in undisturbed sediments and is consistent with current estimates using chloride under these conditions.…”

“…Using data reported by Maher et al (2003) and DePaolo et al (2004) for borehole 299-W22-48, Maher et al (2006) estimated recharge using ratios of 234 U/ 238 U along with estimates of bulk sediment dissolution rates and α-recoil loss of 234 U. Additionally, the authors used the strontium isotope ratio data from Maher et al (2003) to constrain the reaction and infiltration model. Application of this information produced a recharge estimate of 5 ± 2 mm/yr, which they stated was applicable for past periods from hundreds to thousands of years ago.…”

“…Maher et al (2003) used the strontium isotope ratio technique to estimate a recharge rate of 7 ± 3 mm/yr. Maher et al (2006) used the strontium technique along with a uranium isotope technique to refine the recharge estimate to 5 ± 2 mm/yr. In both cases, the estimated rates are similar to the chloride-derived rates of 3.9 mm/yr.…”

Mineralization of carbon dioxide sequestered in volcanogenic sandstone reservoir rocks

“…Multi-component reactive transport models such as TOUGHREACT (Xu et al, 2004) and CrunchFlow (Steefel, 2007) integrate hydrologic transport, aqueous and surface complexation and dissolution/precipitation into a comprehensive network of kinetic and equilibrium pathways. Incorporation of isotopic ratios into such multi-component models has been demonstrated in analysis of vadose zone infiltration rates from temperature dependent equilibrium fractionation of water isotopes (Singleton et al, 2004), plagioclase dissolution from uranium-series isotopes (Maher et al, 2006) and recently the influence of hydrologic transport on measured isotope fractionation in compound-specific stable isotope analysis (Rolle et al, 2010).…”