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Edward T Tipper - One of the best experts on this subject based on the ideXlab platform.
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mg isotope constraints on soil pore fluid chemistry evidence from santa cruz california
Geochimica et Cosmochimica Acta, 2010Co-Authors: Edward T Tipper, Jerome Gaillardet, Pascale Louvat, Francoise Capmas, Art F WhiteAbstract:Abstract Mg isotope ratios (26Mg/24Mg) are reported in soil pore-fluids, rain and seawater, grass and smectite from a 90 kyr old soil, developed on an uplifted marine terrace from Santa Cruz, California. Rain water has an invariant 26Mg/24Mg ratio (expressed as δ 26 Mg ) at −0.79 ± 0.05‰, identical to seawater δ 26 Mg . Detrital smectite (from the base of the soil Profile, and therefore unweathered) has a δ 26 Mg value of 0.11‰, potentially enriched in 26Mg by up to 0.3‰ compared to the bulk silicate Earth Mg isotope composition (although within the range of all terrestrial silicates). The soil pore-waters show a Continuous Profile with depth for δ 26 Mg , ranging from −0.99‰ near the surface to −0.43‰ at the base of the Profile. Shallow pore-waters ( δ 26 Mg values that are similar to, or slightly lower than the rain waters. This implies that the degree of biological cycling of Mg in the pore-waters is relatively small and is quantified as δ 26 Mg grass - δ 26 Mg rain ) of 0.21‰. The deep pore-waters (1–15 m deep) have δ 26 Mg values that are intermediate between the smectite and rain, ranging from −0.76‰ to −0.43‰, and show a similar trend with depth compared to Sr isotope ratios. The similarity between Sr and Mg isotope ratios confirms that the Mg in the pore-waters can be explained by a mixture between rain and smectite derived Mg, despite the fact that Mg and Sr concentrations may be buffered by the exchangeable reservoir. However, whilst Sr isotope ratios in the pore-waters span almost the complete range between mineral and rain inputs, Mg isotopes compositions are much closer to the rain inputs. If Mg and Sr isotope ratios are controlled uniquely by a mixture, the data can be used to estimate the mineral weathering inputs to the pore-waters, by correcting for the rain inputs. This isotopic correction is compared to the commonly used chloride correction for precipitation inputs. A consistent interpretation is only possible if Mg isotope ratios are fractionated either by the precipitation of a secondary Mg bearing phase, not detected by conventional methods, or selective leaching of 24Mg from smectite. There is therefore dual control on the Mg isotopic composition of the pore-waters, mixing of two inputs with distinct isotopic compositions, modified by fractionation. The data provide (1) further evidence for Mg isotope fractionation at the surface of the Earth and (2) the first field evidence of Mg isotope fractionation during uptake by natural plants. The coherent behaviour of Mg isotope ratios in soil environments is encouraging for the development of Mg isotope ratios as a quantitative tracer of both weathering inputs of Mg to waters, and the physicochemical processes that cycle Mg, a major cation linked to the carbon cycle, during continental weathering.
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mg isotope constraints on soil pore fluid chemistry evidence from santa cruz california
Geochimica et Cosmochimica Acta, 2010Co-Authors: Edward T Tipper, Jerome Gaillardet, Pascale Louvat, Francoise Capmas, Art F WhiteAbstract:Mg isotope ratios (26Mg/24Mg) are reported in soil pore-fluids, rain and seawater, grass and smectite from a 90 kyr old soil, developed on an uplifted marine terrace from Santa Cruz, California. Rain water has an invariant 26Mg/24Mg ratio (expressed as δ 26 Mg ) at -0.79 ± 0.05‰, identical to seawater δ 26 Mg . Detrital smectite (from the base of the soil Profile, and therefore unweathered) has a δ 26 Mg value of 0.11‰, potentially enriched in 26Mg by up to 0.3‰ compared to the bulk silicate Earth Mg isotope composition (although within the range of all terrestrial silicates). The soil pore-waters show a Continuous Profile with depth for δ 26 Mg , ranging from -0.99‰ near the surface to -0.43‰ at the base of the Profile. Shallow pore-waters (<1 m) have δ 26 Mg values that are similar to, or slightly lower than the rain waters. This implies that the degree of biological cycling of Mg in the pore-waters is relatively small and is quantified as <32%, calculated using the average Mg isotope enrichment factor between grass and rain ( δ 26 Mg grass - δ 26 Mg rain ) of 0.21‰. The deep pore-waters (1–15 m deep) have δ 26 Mg values that are intermediate between the smectite and rain, ranging from -0.76‰ to -0.43‰, and show a similar trend with depth compared to Sr isotope ratios. The similarity between Sr and Mg isotope ratios confirms that the Mg in the pore-waters can be explained by a mixture between rain and smectite derived Mg, despite the fact that Mg and Sr concentrations may be buffered by the exchangeable reservoir. However, whilst Sr isotope ratios in the pore-waters span almost the complete range between mineral and rain inputs, Mg isotopes compositions are much closer to the rain inputs. If Mg and Sr isotope ratios are controlled uniquely by a mixture, the data can be used to estimate the mineral weathering inputs to the pore-waters, by correcting for the rain inputs. This isotopic correction is compared to the commonly used chloride correction for precipitation inputs. A consistent interpretation is only possible if Mg isotope ratios are fractionated either by the precipitation of a secondary Mg bearing phase, not detected by conventional methods, or selective leaching of 24Mg from smectite. There is therefore dual control on the Mg isotopic composition of the pore-waters, mixing of two inputs with distinct isotopic compositions, modified by fractionation. The data provide (1) further evidence for Mg isotope fractionation at the surface of the Earth and (2) the first field evidence of Mg isotope fractionation during uptake by natural plants. The coherent behaviour of Mg isotope ratios in soil environments is encouraging for the development of Mg isotope ratios as a quantitative tracer of both weathering inputs of Mg to waters, and the physicochemical processes that cycle Mg, a major cation linked to the carbon cycle, during continental weathering.
Art F White - One of the best experts on this subject based on the ideXlab platform.
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mg isotope constraints on soil pore fluid chemistry evidence from santa cruz california
Geochimica et Cosmochimica Acta, 2010Co-Authors: Edward T Tipper, Jerome Gaillardet, Pascale Louvat, Francoise Capmas, Art F WhiteAbstract:Abstract Mg isotope ratios (26Mg/24Mg) are reported in soil pore-fluids, rain and seawater, grass and smectite from a 90 kyr old soil, developed on an uplifted marine terrace from Santa Cruz, California. Rain water has an invariant 26Mg/24Mg ratio (expressed as δ 26 Mg ) at −0.79 ± 0.05‰, identical to seawater δ 26 Mg . Detrital smectite (from the base of the soil Profile, and therefore unweathered) has a δ 26 Mg value of 0.11‰, potentially enriched in 26Mg by up to 0.3‰ compared to the bulk silicate Earth Mg isotope composition (although within the range of all terrestrial silicates). The soil pore-waters show a Continuous Profile with depth for δ 26 Mg , ranging from −0.99‰ near the surface to −0.43‰ at the base of the Profile. Shallow pore-waters ( δ 26 Mg values that are similar to, or slightly lower than the rain waters. This implies that the degree of biological cycling of Mg in the pore-waters is relatively small and is quantified as δ 26 Mg grass - δ 26 Mg rain ) of 0.21‰. The deep pore-waters (1–15 m deep) have δ 26 Mg values that are intermediate between the smectite and rain, ranging from −0.76‰ to −0.43‰, and show a similar trend with depth compared to Sr isotope ratios. The similarity between Sr and Mg isotope ratios confirms that the Mg in the pore-waters can be explained by a mixture between rain and smectite derived Mg, despite the fact that Mg and Sr concentrations may be buffered by the exchangeable reservoir. However, whilst Sr isotope ratios in the pore-waters span almost the complete range between mineral and rain inputs, Mg isotopes compositions are much closer to the rain inputs. If Mg and Sr isotope ratios are controlled uniquely by a mixture, the data can be used to estimate the mineral weathering inputs to the pore-waters, by correcting for the rain inputs. This isotopic correction is compared to the commonly used chloride correction for precipitation inputs. A consistent interpretation is only possible if Mg isotope ratios are fractionated either by the precipitation of a secondary Mg bearing phase, not detected by conventional methods, or selective leaching of 24Mg from smectite. There is therefore dual control on the Mg isotopic composition of the pore-waters, mixing of two inputs with distinct isotopic compositions, modified by fractionation. The data provide (1) further evidence for Mg isotope fractionation at the surface of the Earth and (2) the first field evidence of Mg isotope fractionation during uptake by natural plants. The coherent behaviour of Mg isotope ratios in soil environments is encouraging for the development of Mg isotope ratios as a quantitative tracer of both weathering inputs of Mg to waters, and the physicochemical processes that cycle Mg, a major cation linked to the carbon cycle, during continental weathering.
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mg isotope constraints on soil pore fluid chemistry evidence from santa cruz california
Geochimica et Cosmochimica Acta, 2010Co-Authors: Edward T Tipper, Jerome Gaillardet, Pascale Louvat, Francoise Capmas, Art F WhiteAbstract:Mg isotope ratios (26Mg/24Mg) are reported in soil pore-fluids, rain and seawater, grass and smectite from a 90 kyr old soil, developed on an uplifted marine terrace from Santa Cruz, California. Rain water has an invariant 26Mg/24Mg ratio (expressed as δ 26 Mg ) at -0.79 ± 0.05‰, identical to seawater δ 26 Mg . Detrital smectite (from the base of the soil Profile, and therefore unweathered) has a δ 26 Mg value of 0.11‰, potentially enriched in 26Mg by up to 0.3‰ compared to the bulk silicate Earth Mg isotope composition (although within the range of all terrestrial silicates). The soil pore-waters show a Continuous Profile with depth for δ 26 Mg , ranging from -0.99‰ near the surface to -0.43‰ at the base of the Profile. Shallow pore-waters (<1 m) have δ 26 Mg values that are similar to, or slightly lower than the rain waters. This implies that the degree of biological cycling of Mg in the pore-waters is relatively small and is quantified as <32%, calculated using the average Mg isotope enrichment factor between grass and rain ( δ 26 Mg grass - δ 26 Mg rain ) of 0.21‰. The deep pore-waters (1–15 m deep) have δ 26 Mg values that are intermediate between the smectite and rain, ranging from -0.76‰ to -0.43‰, and show a similar trend with depth compared to Sr isotope ratios. The similarity between Sr and Mg isotope ratios confirms that the Mg in the pore-waters can be explained by a mixture between rain and smectite derived Mg, despite the fact that Mg and Sr concentrations may be buffered by the exchangeable reservoir. However, whilst Sr isotope ratios in the pore-waters span almost the complete range between mineral and rain inputs, Mg isotopes compositions are much closer to the rain inputs. If Mg and Sr isotope ratios are controlled uniquely by a mixture, the data can be used to estimate the mineral weathering inputs to the pore-waters, by correcting for the rain inputs. This isotopic correction is compared to the commonly used chloride correction for precipitation inputs. A consistent interpretation is only possible if Mg isotope ratios are fractionated either by the precipitation of a secondary Mg bearing phase, not detected by conventional methods, or selective leaching of 24Mg from smectite. There is therefore dual control on the Mg isotopic composition of the pore-waters, mixing of two inputs with distinct isotopic compositions, modified by fractionation. The data provide (1) further evidence for Mg isotope fractionation at the surface of the Earth and (2) the first field evidence of Mg isotope fractionation during uptake by natural plants. The coherent behaviour of Mg isotope ratios in soil environments is encouraging for the development of Mg isotope ratios as a quantitative tracer of both weathering inputs of Mg to waters, and the physicochemical processes that cycle Mg, a major cation linked to the carbon cycle, during continental weathering.
Thomas Gimmi - One of the best experts on this subject based on the ideXlab platform.
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identifying temporally and spatially changing boundary conditions at an aquifer aquitard interface using helium in porewater
Applied Geochemistry, 2018Co-Authors: Daniel Rufer, Niklaus H Waber, Thomas GimmiAbstract:Abstract Helium concentrations and 3He/4He isotope ratios of porewater, groundwater and rock were measured on samples collected from a Jurassic sediment sequence at the Mont Terri underground rock laboratory (Northern Switzerland). Porewater He data of rock samples collected from borehole BDB-1 at high spatial resolution across a karstic limestone unit (Passwang Formation) into the underlying claystone sequence (Opalinus Clay, Staffelegg Formation) describe a Continuous Profile from the water-conducting zone in the limestone into the clay-rich rocks of low permeability. Concentrations of 4He, 3He and their parent nuclides in the rock allow calculating in-situ production and accumulation terms. Since the time of sedimentation, 90%–97% of the in-situ produced 4He has been released to the porewater. Today only 2.5% of the maximum possible accumulated 4He is still retained in the porewater while the major part of in-situ produced 4He was removed from the system presumably by porewater–groundwater exchange. The porewater 4He concentrations show a diffusion Profile from the aquitard towards the aquifer, reflecting a) a transient state between 4He in-situ production and porewater–groundwater exchange, b) a transient state from previously higher 4He concentrations in the porewater, and c) a spatially variable boundary in the karstic limestone unit. Evolutionary models of porewater 4He concentration Profiles in combination with constraints from independent chemical and isotopic tracers allow deciphering a complex palaeo-hydrogeological history of the system over about the last 30 ka. A local excursion from the general Profile towards higher 4He concentrations and 3He/4He ratio in a limestone layer in the Opalinus Clay cannot be further constrained in time based on the present sample frequency, but appears to represent a hydrogeological signal.
Shuting Liu - One of the best experts on this subject based on the ideXlab platform.
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switchable textile triboelectric nanogenerators s tengs for Continuous Profile sensing application without environmental interferences
Nano Energy, 2020Co-Authors: Shuting Liu, Hao Wang, Shurong Dong, Chengkuo LeeAbstract:Abstract Conventionally, the output amplitude of triboelectric nanogenerators (TENGs) sensors is detected as the sensing output, where the accuracy and stability are easily affected by environmental interferences such as humidity, temperature and electrostatic coupling with surrounding objects. Meanwhile, the nature of pulse mode voltage output cannot provide information to further generate a detailed Profile of the varying force with time interval when users press a typical TENG working in the contact-separation mode. These two critical issues hinder the TENGs sensors to be competitive with conventionally commercialized sensors. In this study, a switchable textile-triboelectric nanogenerator (S-TENG) is proposed to address these issues. By working on a switchable mode to generate resistor-capacitor (RC) discharging voltage, i.e, enabling capacitive sensing, the capacitance of the TENGs device is not affected by environmental interferences. Moreover, a high-frequency switching approach is investigated to generate a Continuous Profile of time-dependent capacitance as a function of force along time, referring to the Continuous sensing parameter. Therefore, S-TENGs offer the sensory information which could not be achieved by any other TENGs so far.
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a switchable fabric triboelectric nanogenerators sf tengs Profile sensing application
2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS), 2019Co-Authors: Hao Wang, Shuting Liu, Shurong Dong, Chengkuo LeeAbstract:Conventionally, the output amplitude of TENGs sensors is detected as the sensing output, where the accuracy and stability are easily affected by environmental interferences such as humidity, temperature and electrostatic coupling with surrounding objects. Meanwhile, the nature of pulse mode voltage output cannot provide information to further generate detailed Profile of force variation along time interval when users press a typical TENG working in contact-separation mode. These two critical issues stop the TENGs sensors to be competitive with conventionally commercialized sensors.In this study, a switchable textile-triboelectric nanogenerator (S-TENG) is proposed to offer a solution for these issues. By working on a switchable mode to generate RC discharging voltage, i.e, enabling capacitive sensing, the capacitance of TENGs devices is not affected by environmental interferences. Moreover, a high-frequency switching approach is investigated to generate a Continuous Profile of time-dependent capacitance change as a function of force variation along time, referring to the Continuous sensing parameter. Therefore, S-TENGs offer the sensory information which could not be achieved by any other TENGs so far.
Jerome Gaillardet - One of the best experts on this subject based on the ideXlab platform.
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mg isotope constraints on soil pore fluid chemistry evidence from santa cruz california
Geochimica et Cosmochimica Acta, 2010Co-Authors: Edward T Tipper, Jerome Gaillardet, Pascale Louvat, Francoise Capmas, Art F WhiteAbstract:Abstract Mg isotope ratios (26Mg/24Mg) are reported in soil pore-fluids, rain and seawater, grass and smectite from a 90 kyr old soil, developed on an uplifted marine terrace from Santa Cruz, California. Rain water has an invariant 26Mg/24Mg ratio (expressed as δ 26 Mg ) at −0.79 ± 0.05‰, identical to seawater δ 26 Mg . Detrital smectite (from the base of the soil Profile, and therefore unweathered) has a δ 26 Mg value of 0.11‰, potentially enriched in 26Mg by up to 0.3‰ compared to the bulk silicate Earth Mg isotope composition (although within the range of all terrestrial silicates). The soil pore-waters show a Continuous Profile with depth for δ 26 Mg , ranging from −0.99‰ near the surface to −0.43‰ at the base of the Profile. Shallow pore-waters ( δ 26 Mg values that are similar to, or slightly lower than the rain waters. This implies that the degree of biological cycling of Mg in the pore-waters is relatively small and is quantified as δ 26 Mg grass - δ 26 Mg rain ) of 0.21‰. The deep pore-waters (1–15 m deep) have δ 26 Mg values that are intermediate between the smectite and rain, ranging from −0.76‰ to −0.43‰, and show a similar trend with depth compared to Sr isotope ratios. The similarity between Sr and Mg isotope ratios confirms that the Mg in the pore-waters can be explained by a mixture between rain and smectite derived Mg, despite the fact that Mg and Sr concentrations may be buffered by the exchangeable reservoir. However, whilst Sr isotope ratios in the pore-waters span almost the complete range between mineral and rain inputs, Mg isotopes compositions are much closer to the rain inputs. If Mg and Sr isotope ratios are controlled uniquely by a mixture, the data can be used to estimate the mineral weathering inputs to the pore-waters, by correcting for the rain inputs. This isotopic correction is compared to the commonly used chloride correction for precipitation inputs. A consistent interpretation is only possible if Mg isotope ratios are fractionated either by the precipitation of a secondary Mg bearing phase, not detected by conventional methods, or selective leaching of 24Mg from smectite. There is therefore dual control on the Mg isotopic composition of the pore-waters, mixing of two inputs with distinct isotopic compositions, modified by fractionation. The data provide (1) further evidence for Mg isotope fractionation at the surface of the Earth and (2) the first field evidence of Mg isotope fractionation during uptake by natural plants. The coherent behaviour of Mg isotope ratios in soil environments is encouraging for the development of Mg isotope ratios as a quantitative tracer of both weathering inputs of Mg to waters, and the physicochemical processes that cycle Mg, a major cation linked to the carbon cycle, during continental weathering.
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mg isotope constraints on soil pore fluid chemistry evidence from santa cruz california
Geochimica et Cosmochimica Acta, 2010Co-Authors: Edward T Tipper, Jerome Gaillardet, Pascale Louvat, Francoise Capmas, Art F WhiteAbstract:Mg isotope ratios (26Mg/24Mg) are reported in soil pore-fluids, rain and seawater, grass and smectite from a 90 kyr old soil, developed on an uplifted marine terrace from Santa Cruz, California. Rain water has an invariant 26Mg/24Mg ratio (expressed as δ 26 Mg ) at -0.79 ± 0.05‰, identical to seawater δ 26 Mg . Detrital smectite (from the base of the soil Profile, and therefore unweathered) has a δ 26 Mg value of 0.11‰, potentially enriched in 26Mg by up to 0.3‰ compared to the bulk silicate Earth Mg isotope composition (although within the range of all terrestrial silicates). The soil pore-waters show a Continuous Profile with depth for δ 26 Mg , ranging from -0.99‰ near the surface to -0.43‰ at the base of the Profile. Shallow pore-waters (<1 m) have δ 26 Mg values that are similar to, or slightly lower than the rain waters. This implies that the degree of biological cycling of Mg in the pore-waters is relatively small and is quantified as <32%, calculated using the average Mg isotope enrichment factor between grass and rain ( δ 26 Mg grass - δ 26 Mg rain ) of 0.21‰. The deep pore-waters (1–15 m deep) have δ 26 Mg values that are intermediate between the smectite and rain, ranging from -0.76‰ to -0.43‰, and show a similar trend with depth compared to Sr isotope ratios. The similarity between Sr and Mg isotope ratios confirms that the Mg in the pore-waters can be explained by a mixture between rain and smectite derived Mg, despite the fact that Mg and Sr concentrations may be buffered by the exchangeable reservoir. However, whilst Sr isotope ratios in the pore-waters span almost the complete range between mineral and rain inputs, Mg isotopes compositions are much closer to the rain inputs. If Mg and Sr isotope ratios are controlled uniquely by a mixture, the data can be used to estimate the mineral weathering inputs to the pore-waters, by correcting for the rain inputs. This isotopic correction is compared to the commonly used chloride correction for precipitation inputs. A consistent interpretation is only possible if Mg isotope ratios are fractionated either by the precipitation of a secondary Mg bearing phase, not detected by conventional methods, or selective leaching of 24Mg from smectite. There is therefore dual control on the Mg isotopic composition of the pore-waters, mixing of two inputs with distinct isotopic compositions, modified by fractionation. The data provide (1) further evidence for Mg isotope fractionation at the surface of the Earth and (2) the first field evidence of Mg isotope fractionation during uptake by natural plants. The coherent behaviour of Mg isotope ratios in soil environments is encouraging for the development of Mg isotope ratios as a quantitative tracer of both weathering inputs of Mg to waters, and the physicochemical processes that cycle Mg, a major cation linked to the carbon cycle, during continental weathering.