Chemical weathering and lithologic controls of water chemistry in a high-elevation river system: Clark's Fork of the Yellowstone River, Wyoming and Montana

Pyrite is the most common sulfide mineral occurring in sedimentary and igneous rocks and globally contributes a greater flux of sulfate. Large quantity of reactive nitrogen as fertilizers for agricultural production has been released into the environment in China over recent decades. Sulfuric acid formed by oxidative weathering of pyrite (OWP) and nitric acid formed by oxidation of reducing nitrogen fertilizer (ONF) through neutralization with carbonate minerals can counteract CO2 drawdown from chemical weathering. Here, we use the multiple isotopes (13C-DIC, 34S and 18O-SO42&#8211;, 15N and 18O-NO3&#8211;, and 18O and D-H2O) and water chemistry, as well as historical hydrochemical data to assess the roles of strong acids in chemical weathering and the carbon cycle in a karst river system (Chishui River, southwestern China). The variations in alkalinity and the &#948;13C-DIC along with theoretical mixing models demonstrate the involvement of strong acids in carbonate weathering. However, the strong acid weathering flux determined by &#948;13C-DIC and mixing models is considered to be overestimated due to the effects of photosynthesis and degassing of CO2 on &#948;13C-DIC signal. The protons liberated from OWP and ONF can be constrained by water chemistry and isotope techniques with the use of a Bayesian isotope mixing model. The strong acid weathering flux determined using proton information is higher that determined by &#948;13C-DIC and mixing models. This suggests that the additional protons derived from OWP and ONF might be consumed in other ways without affecting the &#948;13C-DIC signals, such as the neutralization of acidic waters. These results indicate that OWP and ONF coupled with carbonate dissolution significantly enhanced the coupling cycles of carbon, nitrogen and sulfur in this river system.

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Impact of sediment–seawater cation exchange on Himalayan chemical weathering fluxes

Earth Surface Dynamics ◽

10.5194/esurf-4-675-2016 ◽

2016 ◽

Vol 4 (3) ◽

pp. 675-684 ◽

Cited By ~ 4

Author(s):

Maarten Lupker ◽

Christian France-Lanord ◽

Bruno Lartiges

Keyword(s):

Cation Exchange ◽

Chemical Weathering ◽

Sediment Load ◽

Relative Proportion ◽

River System ◽

Exchange Capacity ◽

Sediment Flux ◽

Continental Scale ◽

The Impact

Abstract. Continental-scale chemical weathering budgets are commonly assessed based on the flux of dissolved elements carried by large rivers to the oceans. However, the interaction between sediments and seawater in estuaries can lead to additional cation exchange fluxes that have been very poorly constrained so far. We constrained the magnitude of cation exchange fluxes from the Ganga–Brahmaputra river system based on cation exchange capacity (CEC) measurements of riverine sediments. CEC values of sediments are variable throughout the river water column as a result of hydrological sorting of minerals with depth that control grain sizes and surface area. The average CEC of the integrated sediment load of the Ganga–Brahmaputra is estimated ca. 6.5 meq 100 g−1. The cationic charge of sediments in the river is dominated by bivalent ions Ca2+ (76 %) and Mg2+ (16 %) followed by monovalent K+ (6 %) and Na+ (2 %), and the relative proportion of these ions is constant among all samples and both rivers. Assuming a total exchange of exchangeable Ca2+ for marine Na+ yields a maximal additional Ca2+ flux of 28  ×  109 mol yr−1 of calcium to the ocean, which represents an increase of ca. 6 % of the actual river dissolved Ca2+ flux. In the more likely event that only a fraction of the adsorbed riverine Ca2+ is exchanged, not only for marine Na+ but also Mg2+ and K+, estuarine cation exchange for the Ganga–Brahmaputra is responsible for an additional Ca2+ flux of 23  ×  109 mol yr−1, while ca. 27  ×  109 mol yr−1 of Na+, 8  ×  109 mol yr−1 of Mg2+ and 4  ×  109 mol yr−1 of K+ are re-absorbed in the estuaries. This represents an additional riverine Ca2+ flux to the ocean of 5 % compared to the measured dissolved flux. About 15 % of the dissolved Na+ flux, 8 % of the dissolved K+ flux and 4 % of the Mg2+ are reabsorbed by the sediments in the estuaries. The impact of estuarine sediment–seawater cation exchange appears to be limited when evaluated in the context of the long-term carbon cycle and its main effect is the sequestration of a significant fraction of the riverine Na flux to the oceans. The limited exchange fluxes of the Ganga–Brahmaputra relate to the lower than average CEC of its sediment load that do not counterbalance the high sediment flux to the oceans. This can be attributed to the nature of Himalayan river sediment such as low proportion of clays and organic matter.

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Contrasting sediment and water chemistry indicates the extent of the hyporheic zone in a polluted river system.

Geology Geophysics & Environment ◽

10.7494/geol.2016.42.2.151 ◽

2016 ◽

Vol 42 (2) ◽

pp. 151 ◽

Cited By ~ 3

Author(s):

Dariusz Ciszewski ◽

Urszula Aleksander-Kwaterczak

Keyword(s):

Water Chemistry ◽

Hyporheic Zone ◽

River System ◽

Polluted River

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¡Cuba! River Water Chemistry Reveals Rapid Chemical Weathering, the Echo of Uplift, and the Promise of More Sustainable Agriculture

GSA Today ◽

10.1130/gsatg419a.1 ◽

2020 ◽

Vol 30 (3) ◽

pp. 4-10 ◽

Cited By ~ 2

Author(s):

Paul Bierman ◽

Rita Yvelice Sibello Hernández ◽

Amanda H. Schmidt ◽

Héctor Alejandro Cartas Aguila ◽

Yoelvis Bolaños Alvarez ◽

...

Keyword(s):

Sustainable Agriculture ◽

Water Chemistry ◽

River Water ◽

Chemical Weathering ◽

River Water Chemistry

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Stable Strontium Isotopic Compositions of River Water, Groundwater and Sediments From the Ganges–Brahmaputra–Meghna River System in Bangladesh

Frontiers in Earth Science ◽

10.3389/feart.2021.592062 ◽

2021 ◽

Vol 9 ◽

Author(s):

Toshihiro Yoshimura ◽

Shigeyuki Wakaki ◽

Hodaka Kawahata ◽

H. M. Zakir Hossain ◽

Takuya Manaka ◽

...

Keyword(s):

River Water ◽

Chemical Weathering ◽

Drainage Basin ◽

Dissolution Kinetics ◽

River System ◽

Ganges River ◽

Brahmaputra River ◽

Terrestrial Water ◽

Stable Strontium ◽

The Ganges

The Sr isotopic composition of rivers and groundwaters in the Bengal Plain is a major contributor to the global oceanic Sr inventory. The stable strontium isotope ratios (δ88Sr) provide a new tool to identify chemical weathering reactions in terrestrial water. In this study, we investigated the spatiotemporal variations of δ88Sr in samples of river water, bedload sediment, and groundwater collected from the Ganges–Brahmaputra–Meghna drainage basin in Bangladesh, which is known to strongly influence the 87Sr/86Sr ratio in seawater. The average δ88Sr values of waters of the Ganges, Brahmaputra, and Meghna rivers were 0.269, 0.316, and 0.278‰, respectively. Our data showed little difference between seasons of high and low discharge. The δ88Sr values measured in sequential leaching fractions of sediments varied from –0.258 to 0.516‰ and were highest in the silicate fraction, followed in turn by the carbonate fraction and the exchangeable fraction. Both 87Sr/86Sr and δ88Sr of these waters are primarily controlled by the inputs of Sr in weathering products from the Bengal Plain and Sr from the Himalayan rivers (Ganges and Brahmaputra). Values of δ88Sr and Sr/Ca were higher in the Brahmaputra River than in the Ganges River, a difference we attribute to greater input from silicate weathering. The variations of δ88Sr and 87Sr/86Sr were greater in groundwater than in river waters. Mineral sorting effects and dissolution kinetics can account for the large scatter in 87Sr/86Sr and δ88Sr values. The depth profile of δ88Sr showed wide variation at shallow depths and convergence to a narrow range of about 0.31‰ at depths greater than 70 m, which reflects more complete equilibration of chemical interactions between groundwater and ambient sediments owing to the longer residence time of deeper groundwater. We found that δ88Sr values in the groundwater of Bangladesh were almost identical to those of river water from the lower Meghna River downstream of its confluence with the Ganges–Brahmaputra river system, thus confirming that the δ88Sr composition of the groundwater discharge to the Bay of Bengal is very similar to that of the river discharge.

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Significant stream chemistry response to temperature variations in a high-elevation mountain watershed

Communications Earth & Environment ◽

10.1038/s43247-020-00039-w ◽

2020 ◽

Vol 1 (1) ◽

Cited By ~ 2

Author(s):

Wei Zhi ◽

Kenneth H. Williams ◽

Rosemary W. H. Carroll ◽

Wendy Brown ◽

Wenming Dong ◽

...

Keyword(s):

Water Chemistry ◽

High Elevation ◽

Stream Chemistry ◽

Earth System ◽

Mountain Regions ◽

Temperature Variations ◽

Mountain Watershed ◽

Air Temperatures ◽

Central Rocky Mountains ◽

Response To Temperature

Abstract High-elevation mountain regions, central to global freshwater supply, are experiencing more rapid warming than low-elevation locations. High-elevation streams are therefore potentially critical indicators for earth system and water chemistry response to warming. Here we present concerted hydroclimatic and biogeochemical data from Coal Creek, Colorado in the central Rocky Mountains at elevations of 2700 to 3700 m, where air temperatures have increased by about 2 °C since 1980. We analyzed water chemistry every other day from 2016 to 2019. Water chemistry data indicate distinct responses of different solutes to inter-annual hydroclimatic variations. Specifically, the concentrations of solutes from rock weathering are stable inter-annually. Solutes that are active in soils, including dissolved organic carbon, vary dramatically, with double to triple peak concentrations occurring during snowmelt and in warm years. We advocate for consistent and persistent monitoring of high elevation streams to record early glimpse of earth surface response to warming.

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Constraints on water chemistry by chemical weathering in the Lake Qinghai catchment, northeastern Tibetan Plateau (China): clues from Sr and its isotopic geochemistry

Hydrogeology Journal ◽

10.1007/s10040-009-0480-9 ◽

2009 ◽

Vol 17 (8) ◽

pp. 2037-2048 ◽

Cited By ~ 28

Author(s):

Zhangdong Jin ◽

Jimin Yu ◽

Sumin Wang ◽

Fei Zhang ◽

Yuewei Shi ◽

...

Keyword(s):

Tibetan Plateau ◽

Water Chemistry ◽

Chemical Weathering ◽

Lake Qinghai ◽

Northeastern Tibetan Plateau ◽

Isotopic Geochemistry

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Sediment residence time variations in an Alpine river system inferred by uranium activity ratio.

10.5194/egusphere-egu2020-6181 ◽

2020 ◽

Author(s):

Maude Thollon ◽

Anthony Dosseto ◽

Samuel Toucanne ◽

Germain Bayon

Keyword(s):

Residence Time ◽

Chemical Weathering ◽

Activity Ratio ◽

River System ◽

Uranium Isotopes ◽

Soil Thickness ◽

Thickness Prediction ◽

Geomorphological Parameters ◽

The One ◽

Physical And Chemical

The sediment residence time represents the time elapsed since the formation of the sediment in soils until its deposition. In order to better constrain timescales of sedimentary processes (erosion, transport, and deposition), it is important to understand to what extent sediment residence time is controlled by geomorphological parameters (e.g. elevation, curvature, slope). Uranium isotopes have been used to infer the time elapsed since the formation of fine detrital grains (<63 &#181;m) by physical and chemical weathering (i.e. comminution age).In this study, uranium isotopes were measured in fluvial sediments (<63 &#181;m) sampled at different locations in a catchment (Var, France) to determine the variation of uranium activity ratio (234U/238U) along the river profile. The absence of fluvial plain implies that the sediment residence time mainly represents the storage time on hillslopes, as sediment transport is expected to be very rapid in this mountainous sedimentary system.&#160;The catchment was divided into 27 sub-catchments to investigate the variability of the geomorphological parameters that have been extracted from spatial analysis. Additionally, sediment residence time was estimated based on soil thickness prediction data combined with denudation rate information to compare this predicted residence time to the one calculated with (234U/238U).The correlation between (234U/238U) and the estimated sediment residence time confirms that (234U/238U) can be modelled to infer sediment residence time. Furthermore, the correlations between the slope, the elevation and (234U/238U) highlight the geomorphological controls on the sediment residence time. The use of (234U/238U) in sedimentary archives will help to determine past geomorphological variations and re-construct past links between catchment erosion and climate change.

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