Using Strontium Isotopes in Conjunction with Major, and Trace Elements to Identify Water/Rock Interaction in the Upper Kittitas County, Washington

The complex bedrock lithologies in the Upper Kittitas County provide an ideal setting for developing isotopic methodology to identify groundwater sources and track flow paths through water-rock interaction. A wide range of 87Sr/86Sr (0.7040 to 0.7068) in surface waters, springs, and groundwater from wells was found, allowing for identification of the individual signatures of lithologic units. Rock leachates from different lithology were compared to water samples to determine a general 87Sr/86Sr signature of the water-rock interaction for that lithology. The signatures identified were systematically lower than their associated waters, but similar enough to identify the expected 87Sr/86Sr of water-rock interaction for most of the units. These signatures can then be compared to unknown waters to identify the source and/or mixing between sources. Using this method, many of the water samples in this study were directly correlated to their sources. The greatest limitations of this method were lithologies that were not geochemically homogenous and overlap in ranges of 87Sr/86Sr for different lithology

Geochemical Analysis of Surface and Ground Waters Around Cle Elum, WA; Implications for the Proposed Exempt Well Moratorium

The Yakima River drainage is one of the most heavily irrigated regions in the state, and water use has been much contested and litigated. Due to this water demand and the increase in drilling of domestic wells, a moratorium on exempt well drilling was proposed in 2007. In this study geochemical data is used to evaluate the surface-groundwater interaction in the area around Cle Elum, WA. The hydrogeology of this area is poorly understood due to the complex stratigraphy where the valley floor meets the bedrock of the Cascade Range. It is important to understand the relationship between groundwater and surface water because more than the available surface water in the Yakima drainage is appropriated and many water rights holders depend on this water for their livelihood. This study began as a class project for an Environmental Geochemistry class at Central Washington University. Students collected samples from over 30 domestic wells and nearby surface water sources in the Cle Elum/Roslyn area. Trace element and major ion data are presented for these samples and are used along with geochemical analysis to draw conclusions regarding the different sub-surface water bearing units as well as the relationship between the surface and ground waters. This report concludes that exempt wells need monitoring and suggests the current policy of over-appropriation be reviewed

Geochemical Analysis of Surface and Ground Waters Around Cle Elum, WA; Implications for the Proposed Exempt Well Moratorium

The Yakima River drainage is one of the most heavily irrigated regions in the state, and water use has been much contested and litigated. Due to this water demand and the increase in drilling of domestic wells, a moratorium on exempt well drilling was proposed in 2007. In this study geochemical data is used to evaluate the surface-groundwater interaction in the area around Cle Elum, WA. The hydrogeology of this area is poorly understood due to the complex stratigraphy where the valley floor meets the bedrock of the Cascade Range. It is important to understand the relationship between groundwater and surface water because more than the available surface water in the Yakima drainage is appropriated and many water rights holders depend on this water for their livelihood. This study began as a class project for an Environmental Geochemistry class at Central Washington University. Students collected samples from over 30 domestic wells and nearby surface water sources in the Cle Elum/Roslyn area. Trace element and major ion data are presented for these samples and are used along with geochemical analysis to draw conclusions regarding the different sub-surface water bearing units as well as the relationship between the surface and ground waters. This report concludes that exempt wells need monitoring and suggests the current policy of over-appropriation be reviewed

Geographic classification of U.S. Washington State wines using elemental and water isotope composition

Wine fraud leaves wineries vulnerable to damage in reputation and potential lost revenue. To reduce this risk for wines from Washington State (WA), USA, advanced analytical instrumentation and statistical methods were employed to geographically classify 133 wines from 4 major wine producing regions, including 70 wines from WA. Analyses of 37 elements and 2 water isotopes were performed with Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry and Cavity Ring-Down Spectroscopy, respectively. Linear discriminant analysis resulted in 96.2% discrimination, achieved with 11 parameters (Mn, Zn, Pb, Ni, As, D/H, La, Ce, Si, Zr and Sr) that were linearly combined into 3 functions. WA wines were uniquely distinguished in large part with low D/H ratios and Mn concentrations derived from the isotopically light precipitation and volcanic loess soils encountered in this region, respectively. This study is the first of its kind to focus on the authentication of WA wines

An isotopic study of the fluid flow and thermal history of the 2.8 Ma Chegem ash-flow caldera and related intrusive rocks (Caucasus Mountains, Russia)

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The 2.8 Ma Chegem caldera, an 11x15 km ash-flow caldera located in the Caucasus Mountains, presents a unique opportunity to study silicic magma systems because of its combination of youth, exposure and simplicity. Rapid uplift and erosion in the region has exposed over 2 km of flatlying caldera fill, consisting of densely welded tuff (rhyolitic to dacitic), overlain by glacial deposits and andesite flows and cut by a granodiorite porphyry intrusion. The Eldjurta Granite, whose age and composition are similar to the Chegem volcanics, is exposed in an adjacent river valley 10 km to the northeast. Major Mo-W deposits located in nearby skarns have prompted mineral-exploration drillholes (to 4 km depth) in the granite. An isotopic study of the rocks of the Chegem caldera and the Eldjurta Granite has been performed to examine their petrogenesis, fluid flow and thermal histories. Biotite and sanidine [...] ages for 8 Chegem Tuff samples and the granodiorite intrusion are analytically indistinguishable at 2.82 ± 0.02 Ma. Thus, the Chegem Tuff was erupted, cooled and intruded by the granodiorite within < 50,000 yrs. In the nearby Eldjurta Granite, biotite and K-feldspar [...] ages for 11 samples, including 8 from the deep drillhole (to 3970m depth) yield ages between 0.83 ± 0.29 Ma and 2.78 ± 0.09 Ma. A decrease in biotite ages from 1.90 ± 0.24 Ma near the roof of the granite to 0.83 ± 0.29 Ma at 3970m depth, apparently records the uplift and cooling history of this pluton. The ages of the upper 10 samples imply an isotherm migration rate of 13 mm/yr, probably due to a combination of downward migration of isotherms and regional uplift. Oxygen isotope studies of the intracaldera tuff, including 38 samples from a continuous 1405m-stratigraphic section, reveal a striking caldera-wide stratigraphic horizon of [...]-depleted rocks in which there is extreme disequilibrium between phenocrysts and groundmass (sometimes still glassy). All quartz and feldspar phenocrysts have "normal" igneous [...] values of [...]8.5 and [...]7.0, respectively. Whole-rock and groundmass [...] values are as low as -4.0 and -7.7, respectively. Infrared spectroscopic analyses of glassy pumices reveal that they contain 3.3 to 4.8 wt% water. The [...] and water speciation of these glasses reflects low-temperature hydration by meteoric water, whereas some of their [...] values require higher temperature water-glass interaction. Pronounced disequilibrium between coexisting feldspar and groundmass or glass has never been observed before on this scale. It requires a hydrothermal event involving large amounts of low-[...] H2O at sufficiently high temperatures and short enough time that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the [...] depletions at Chegem is a high-temperature (500-600°C), short-lived (10-25 years), vigorous meteoric-hydrothermal event similar to that which occurred at the Valley of Ten Thousand Smokes, Alaska. Mass balance calculations indicate fluid fluxes of [...] mol/[...]-sec over that time period. Sr isotopic studies reveal that this hydrothermal event caused increases in whole-rock [...], possibly because the hydrothermal waters attained radiogenic Sr from crystalline rocks which were incorporated in the caldera fill during caldera collapse. [...] ratios of unaltered Chegem volcanic and intrusive rocks range from 0.7044 to 0.7060, significantly lower than values for surrounding country rock (0.7070 to 0.7319). Thus, the Chegem magmas were probably derived from the mantle or lower crust. The [...] ratios correlate with major- and trace-element trends, indicating that the Chegem magma chamber was both isotopically and compositionally zoned. Compared to the Chegem rocks, the Eldjurta Granite has higher [...] (0.7069), [...] and [...], and so must have evolved separately at some time

Chegem sample location map: Supplement 2 from "An isotopic study of the fluid flow and thermal history of the 2.8 Ma Chegem ash-flow caldera and related intrusive rocks (Caucasus Mountains, Russia)" (Thesis)

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The 2.8 Ma Chegem caldera, an 11x15 km ash-flow caldera located in the Caucasus Mountains, presents a unique opportunity to study silicic magma systems because of its combination of youth, exposure and simplicity. Rapid uplift and erosion in the region has exposed over 2 km of flatlying caldera fill, consisting of densely welded tuff (rhyolitic to dacitic), overlain by glacial deposits and andesite flows and cut by a granodiorite porphyry intrusion. The Eldjurta Granite, whose age and composition are similar to the Chegem volcanics, is exposed in an adjacent river valley 10 km to the northeast. Major Mo-W deposits located in nearby skarns have prompted mineral-exploration drillholes (to 4 km depth) in the granite. An isotopic study of the rocks of the Chegem caldera and the Eldjurta Granite has been performed to examine their petrogenesis, fluid flow and thermal histories. Biotite and sanidine [...] ages for 8 Chegem Tuff samples and the granodiorite intrusion are analytically indistinguishable at 2.82 ± 0.02 Ma. Thus, the Chegem Tuff was erupted, cooled and intruded by the granodiorite within &lt; 50,000 yrs. In the nearby Eldjurta Granite, biotite and K-feldspar [...] ages for 11 samples, including 8 from the deep drillhole (to 3970m depth) yield ages between 0.83 ± 0.29 Ma and 2.78 ± 0.09 Ma. A decrease in biotite ages from 1.90 ± 0.24 Ma near the roof of the granite to 0.83 ± 0.29 Ma at 3970m depth, apparently records the uplift and cooling history of this pluton. The ages of the upper 10 samples imply an isotherm migration rate of 13 mm/yr, probably due to a combination of downward migration of isotherms and regional uplift. Oxygen isotope studies of the intracaldera tuff, including 38 samples from a continuous 1405m-stratigraphic section, reveal a striking caldera-wide stratigraphic horizon of [...]-depleted rocks in which there is extreme disequilibrium between phenocrysts and groundmass (sometimes still glassy). All quartz and feldspar phenocrysts have "normal" igneous [...] values of [...]8.5 and [...]7.0, respectively. Whole-rock and groundmass [...] values are as low as -4.0 and -7.7, respectively. Infrared spectroscopic analyses of glassy pumices reveal that they contain 3.3 to 4.8 wt% water. The [...] and water speciation of these glasses reflects low-temperature hydration by meteoric water, whereas some of their [...] values require higher temperature water-glass interaction. Pronounced disequilibrium between coexisting feldspar and groundmass or glass has never been observed before on this scale. It requires a hydrothermal event involving large amounts of low-[...] H2O at sufficiently high temperatures and short enough time that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the [...] depletions at Chegem is a high-temperature (500-600°C), short-lived (10-25 years), vigorous meteoric-hydrothermal event similar to that which occurred at the Valley of Ten Thousand Smokes, Alaska. Mass balance calculations indicate fluid fluxes of [...] mol/[...]-sec over that time period. Sr isotopic studies reveal that this hydrothermal event caused increases in whole-rock [...], possibly because the hydrothermal waters attained radiogenic Sr from crystalline rocks which were incorporated in the caldera fill during caldera collapse. [...] ratios of unaltered Chegem volcanic and intrusive rocks range from 0.7044 to 0.7060, significantly lower than values for surrounding country rock (0.7070 to 0.7319). Thus, the Chegem magmas were probably derived from the mantle or lower crust. The [...] ratios correlate with major- and trace-element trends, indicating that the Chegem magma chamber was both isotopically and compositionally zoned. Compared to the Chegem rocks, the Eldjurta Granite has higher [...] (0.7069), [...] and [...], and so must have evolved separately at some time

Geologic map of the central Greater Caucasus Mountain Range: Supplement 1 from "An isotopic study of the fluid flow and thermal history of the 2.8 Ma Chegem ash-flow caldera and related intrusive rocks (Caucasus Mountains, Russia)" (Thesis)

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The 2.8 Ma Chegem caldera, an 11x15 km ash-flow caldera located in the Caucasus Mountains, presents a unique opportunity to study silicic magma systems because of its combination of youth, exposure and simplicity. Rapid uplift and erosion in the region has exposed over 2 km of flatlying caldera fill, consisting of densely welded tuff (rhyolitic to dacitic), overlain by glacial deposits and andesite flows and cut by a granodiorite porphyry intrusion. The Eldjurta Granite, whose age and composition are similar to the Chegem volcanics, is exposed in an adjacent river valley 10 km to the northeast. Major Mo-W deposits located in nearby skarns have prompted mineral-exploration drillholes (to 4 km depth) in the granite. An isotopic study of the rocks of the Chegem caldera and the Eldjurta Granite has been performed to examine their petrogenesis, fluid flow and thermal histories. Biotite and sanidine [...] ages for 8 Chegem Tuff samples and the granodiorite intrusion are analytically indistinguishable at 2.82 ± 0.02 Ma. Thus, the Chegem Tuff was erupted, cooled and intruded by the granodiorite within &lt; 50,000 yrs. In the nearby Eldjurta Granite, biotite and K-feldspar [...] ages for 11 samples, including 8 from the deep drillhole (to 3970m depth) yield ages between 0.83 ± 0.29 Ma and 2.78 ± 0.09 Ma. A decrease in biotite ages from 1.90 ± 0.24 Ma near the roof of the granite to 0.83 ± 0.29 Ma at 3970m depth, apparently records the uplift and cooling history of this pluton. The ages of the upper 10 samples imply an isotherm migration rate of 13 mm/yr, probably due to a combination of downward migration of isotherms and regional uplift. Oxygen isotope studies of the intracaldera tuff, including 38 samples from a continuous 1405m-stratigraphic section, reveal a striking caldera-wide stratigraphic horizon of [...]-depleted rocks in which there is extreme disequilibrium between phenocrysts and groundmass (sometimes still glassy). All quartz and feldspar phenocrysts have "normal" igneous [...] values of [...]8.5 and [...]7.0, respectively. Whole-rock and groundmass [...] values are as low as -4.0 and -7.7, respectively. Infrared spectroscopic analyses of glassy pumices reveal that they contain 3.3 to 4.8 wt% water. The [...] and water speciation of these glasses reflects low-temperature hydration by meteoric water, whereas some of their [...] values require higher temperature water-glass interaction. Pronounced disequilibrium between coexisting feldspar and groundmass or glass has never been observed before on this scale. It requires a hydrothermal event involving large amounts of low-[...] H2O at sufficiently high temperatures and short enough time that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the [...] depletions at Chegem is a high-temperature (500-600°C), short-lived (10-25 years), vigorous meteoric-hydrothermal event similar to that which occurred at the Valley of Ten Thousand Smokes, Alaska. Mass balance calculations indicate fluid fluxes of [...] mol/[...]-sec over that time period. Sr isotopic studies reveal that this hydrothermal event caused increases in whole-rock [...], possibly because the hydrothermal waters attained radiogenic Sr from crystalline rocks which were incorporated in the caldera fill during caldera collapse. [...] ratios of unaltered Chegem volcanic and intrusive rocks range from 0.7044 to 0.7060, significantly lower than values for surrounding country rock (0.7070 to 0.7319). Thus, the Chegem magmas were probably derived from the mantle or lower crust. The [...] ratios correlate with major- and trace-element trends, indicating that the Chegem magma chamber was both isotopically and compositionally zoned. Compared to the Chegem rocks, the Eldjurta Granite has higher [...] (0.7069), [...] and [...], and so must have evolved separately at some time

A portion of the Valley of Ten Thousand Smokes in 1917: Supplement 3 from "An isotopic study of the fluid flow and thermal history of the 2.8 Ma Chegem ash-flow caldera and related intrusive rocks (Caucasus Mountains, Russia)" (Thesis)

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The 2.8 Ma Chegem caldera, an 11x15 km ash-flow caldera located in the Caucasus Mountains, presents a unique opportunity to study silicic magma systems because of its combination of youth, exposure and simplicity. Rapid uplift and erosion in the region has exposed over 2 km of flatlying caldera fill, consisting of densely welded tuff (rhyolitic to dacitic), overlain by glacial deposits and andesite flows and cut by a granodiorite porphyry intrusion. The Eldjurta Granite, whose age and composition are similar to the Chegem volcanics, is exposed in an adjacent river valley 10 km to the northeast. Major Mo-W deposits located in nearby skarns have prompted mineral-exploration drillholes (to 4 km depth) in the granite. An isotopic study of the rocks of the Chegem caldera and the Eldjurta Granite has been performed to examine their petrogenesis, fluid flow and thermal histories. Biotite and sanidine [...] ages for 8 Chegem Tuff samples and the granodiorite intrusion are analytically indistinguishable at 2.82 ± 0.02 Ma. Thus, the Chegem Tuff was erupted, cooled and intruded by the granodiorite within &lt; 50,000 yrs. In the nearby Eldjurta Granite, biotite and K-feldspar [...] ages for 11 samples, including 8 from the deep drillhole (to 3970m depth) yield ages between 0.83 ± 0.29 Ma and 2.78 ± 0.09 Ma. A decrease in biotite ages from 1.90 ± 0.24 Ma near the roof of the granite to 0.83 ± 0.29 Ma at 3970m depth, apparently records the uplift and cooling history of this pluton. The ages of the upper 10 samples imply an isotherm migration rate of 13 mm/yr, probably due to a combination of downward migration of isotherms and regional uplift. Oxygen isotope studies of the intracaldera tuff, including 38 samples from a continuous 1405m-stratigraphic section, reveal a striking caldera-wide stratigraphic horizon of [...]-depleted rocks in which there is extreme disequilibrium between phenocrysts and groundmass (sometimes still glassy). All quartz and feldspar phenocrysts have "normal" igneous [...] values of [...]8.5 and [...]7.0, respectively. Whole-rock and groundmass [...] values are as low as -4.0 and -7.7, respectively. Infrared spectroscopic analyses of glassy pumices reveal that they contain 3.3 to 4.8 wt% water. The [...] and water speciation of these glasses reflects low-temperature hydration by meteoric water, whereas some of their [...] values require higher temperature water-glass interaction. Pronounced disequilibrium between coexisting feldspar and groundmass or glass has never been observed before on this scale. It requires a hydrothermal event involving large amounts of low-[...] H2O at sufficiently high temperatures and short enough time that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the [...] depletions at Chegem is a high-temperature (500-600°C), short-lived (10-25 years), vigorous meteoric-hydrothermal event similar to that which occurred at the Valley of Ten Thousand Smokes, Alaska. Mass balance calculations indicate fluid fluxes of [...] mol/[...]-sec over that time period. Sr isotopic studies reveal that this hydrothermal event caused increases in whole-rock [...], possibly because the hydrothermal waters attained radiogenic Sr from crystalline rocks which were incorporated in the caldera fill during caldera collapse. [...] ratios of unaltered Chegem volcanic and intrusive rocks range from 0.7044 to 0.7060, significantly lower than values for surrounding country rock (0.7070 to 0.7319). Thus, the Chegem magmas were probably derived from the mantle or lower crust. The [...] ratios correlate with major- and trace-element trends, indicating that the Chegem magma chamber was both isotopically and compositionally zoned. Compared to the Chegem rocks, the Eldjurta Granite has higher [...] (0.7069), [...] and [...], and so must have evolved separately at some time

Solution and shock-induced exsolution of argon in vitreous carbon

Carbon has been shown by several researchers to be the main noble-gas carrier in chondritic meteorites. To add to our knowledge of noble gas solution and exsolution in carbonaceous material, experiments were performed on vitreous carbon, a type of amorphous carbon. Ar-rich vitreous carbon samples were prepared under vapor-saturated conditions using argon as the pressurizing medium. Solubility data were obtained for temperatures of 773 to 973K and pressures of 250 to 1500 bars. Up to 7 wt.% Ar was dissolved in the carbon. The solubility data were compared to a thermodynamic model of argon atoms dissolving into a fixed population of “holes” in the carbon. Two variations of the model yielded estimates of the enthalpy of solution of Ar in vitreous carbon (ΔH°_(Ar)) of ≈ −4700 cal/mole. Preliminary shock experiments showed that 28% of the total argon was released by driving 4 GPa^* shocks into the argon-rich carbon. It was demonstrated that shock-induced argon loss is not simply caused by the impact-induced diminution of grain size. The present value of shock pressure required for partial impact devolatilization of Ar from carbon is below the range (5–30 GPa) that H_2O is released from phyllosilicates

Isotope Investigation of Nitrate in Soils and Agricultural Drains of the Lower Yakima Valley, Washington

Nitrate in the groundwater of the lower Yakima Valley, Washington frequently exceeds the Environmental Protection Agency (EPA) maximum contaminant level standard for potable water (10 mg/L), impacting communities with disadvantaged socioeconomic status. Nitrogen and oxygen isotopic signatures were determined for nitrate in soil leachates and irrigation return flow. Isotope signatures for nitrate from soil leachate had significant overlap with both the isotope signatures of naturally occurring soil nitrate at the nearby Hanford site, Washington and of groundwater nitrate attributed to manure and fertilizer application in a local EPA study. A mass balance calculation using Δ17O data suggests that there is a consistent ∼9% atmospheric contribution to nitrate in soil accumulations below caliche layers at several locations. This agrees with other research on the atmospheric contribution to naturally occurring soil nitrates in areas with similar mean annual precipitation values. We argue that this consistent ∼9% atmospheric component indicates that soil nitrate at depth is dominated by naturally occurring, biologically fixed nitrate across multiple sites. We suggest the flushing of naturally occurring soil nitrate to groundwater during land use conversion to irrigated agriculture may represent a previously overlooked significant nitrate input to aquifers in this region