scholarly journals The calculation of water-rock ratios using trace element (Li, B) stable isotopes

2017 ◽  
Vol 71 ◽  
pp. 79
Author(s):  
Laurent Simon ◽  
Christophe Lécuyer ◽  
Thibaut Putelat
Keyword(s):  
Mass Balance ◽  
Isotopic Exchange ◽  
Open Systems ◽  
Elemental Distribution ◽  
Sr Isotope ◽  
Balance Equations ◽  
Rock Interaction ◽  
Circulating Water ◽  
Li Isotope ◽  
Water Rock Interaction

The amount of aqueous fluids circulating into the oceanic crust can be estimated using mass balance equations based on stable isotope exchange between rock and water. Unlike oxygen and strontium, isotopic exchange of trace elements (such as B or Li) between fluids and rocks, operates along with a chemical evolution of the rocks (e.g. a large enrichment of B or Li) that must be integrated into any model of water-rock interaction. We propose a general dimensionless mass balance equation for single-pass open systems that describes the equilibrium elemental distribution and the isotopic composition of reacting rocks as a function of the amount of circulating water. Water-rock ratios calculated from B compositions of hydrothermally-altered basalts range from 8 to 100. They are lower than those previously published (most W/R > 300) but comparable to those inferred from Sr isotope ratios measured in the same samples (3 < W/R < 30). Similar low water-rock ratios from 2 to 20 are calculated from Li isotope compositions of altered basalts and serpentinized peridotites.

scholarly journals The Origin of Major Ions of Groundwater in a Loess Aquifer

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2464 ◽  
Author(s):  
Tianming Huang ◽  
Baoqiang Ma
Keyword(s):  
Atmospheric Deposition ◽  
Mass Balance ◽  
Major Ions ◽  
Average Concentration ◽  
Limiting Factor ◽  
Ionic Charge ◽  
Fresh Groundwater ◽  
Rock Interaction ◽  
Geochemical Mass Balance ◽  
Water Rock Interaction

When groundwater represents most of the world’s reserves of unfrozen freshwaters, water quality is commonly a limiting factor in quantifying usable fresh groundwater storage, especially in arid and semi-arid areas. Tracing the origin of major ions is important to the understanding of hydrochemical evolution and water–rock interaction. Strontium (Sr) and calcium (Ca) are geochemically similar in terms of ionic radius and ionic charge and can substitute for each other in mineral lattices such as in carbonates and silicates. This allows the use of Sr as a proxy for Ca during water–rock interaction. Geochemical mass balance and carbon and strontium isotope techniques were employed to study the origin of each major ion (such as Na, Ca, Mg, Cl, and SO4) in a loess aquifer (there is 10% to 20% of carbonate in the loess). Geochemical mass balance between atmospheric deposition and groundwater shows that the Cl (average concentration of 5.5 mg/L) and SO4 (average concentration of 6.8 mg/L) in groundwater originated from atmospheric deposition. The dissolution of loess using acetic acid was used to analyze the 87Sr/86Sr ratio of carbonate (mainly deposited in continental environments). Groundwater 87Sr/86Sr ratios (0.710677 to 0.712319) are consistent with 87Sr/86Sr ratios in carbonate (0.710329 to 0.711085) but are significantly lower than the whole-rock (0.715136 to 0.717155) and residue (0.719091 to 0.720438), suggesting that Ca and Mg mainly originated from the dissolution of carbonate in the loess aquifer. However, Na originated from the dissolution of albite, suggesting saturation controls the ability of dissolution. There are cation exchanges between Ca + Mg and Na, resulting in Na concentration increases and Ca + Mg concentration decreases in groundwater. This study is important to the understand of the origin of the major ions in groundwater and the geochemical processes in silicate-carbonate aquifers.

87SR/86SR, δ18O AND NOBLE GASES AS TRACERS OF WATER-ROCK INTERACTION IN THE THEISTAREYKIR GEOTHERMAL FIELD

2020 ◽  
Author(s):  
Marie Haut-Labourdette ◽  
◽  
Daniele Pinti ◽  
André Poirier ◽  
Marion Saby ◽  
...  
Keyword(s):  
Noble Gases ◽  
Geothermal Field ◽  
Rock Interaction ◽  
Water Rock Interaction

scholarly journals Geochemical and isotopic evidence of groundwater salinization processes in the Essaouira region, north-west coast, Morocco

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Otman EL Mountassir ◽  
Mohammed Bahir ◽  
Driss Ouazar ◽  
Abdelghani Chehbouni ◽  
Paula M. Carreira
Keyword(s):  
Groundwater Recharge ◽  
West Coast ◽  
Exchange Process ◽  
Environmental Isotopes ◽  
Annual Rainfall ◽  
Groundwater Salinization ◽  
Rock Interaction ◽  
North West ◽  
The North ◽  
Water Rock Interaction

AbstractThe city of Essaouira is located along the north-west coast of Morocco, where groundwater is the main source of drinking, domestic and agricultural water. In recent decades, the salinity of groundwater has increased, which is why geochemical techniques and environmental isotopes have been used to determine the main sources of groundwater recharge and salinization. The hydrochemical study shows that for the years 1995, 2007, 2016 and 2019, the chemical composition of groundwater in the study area consists of HCO3–Ca–Mg, Cl–Ca–Mg, SO4–Ca and Cl–Na chemical facies. The results show that from 1995 to 2019, electrical conductivity increased and that could be explained by a decrease in annual rainfall in relation to climate change and water–rock interaction processes. Geochemical and environmental isotope data show that the main geochemical mechanisms controlling the hydrochemical evolution of groundwater in the Cenomanian–Turonian aquifer are the water–rock interaction and the cation exchange process. The diagram of δ2H = 8 * δ18O + 10 shows that the isotopic contents are close or above to the Global Meteoric Water Line, which suggests that the aquifer is recharged by precipitation of Atlantic origin. In conclusion, groundwater withdrawal should be well controlled to prevent groundwater salinization and further intrusion of seawater due to the lack of annual groundwater recharge in the Essaouira region.

scholarly journals Water–rock interaction and the concentrations of major, trace, and rare earth elements in hydrocarbon-associated produced waters of the United States

2021 ◽  
Author(s):  
Carleton R. Bern ◽  
Justin E. Birdwell ◽  
Aaron M. Jubb
Keyword(s):  
United States ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Water Chemistry ◽  
Produced Water ◽  
The United States ◽  
Rock Interaction ◽  
Produced Waters ◽  
Water Rock Interaction

Comparisons of hydrocarbon-produced waters from multiple basins and experiments using multiple shales illustrate water–rock interaction influence on produced water chemistry.

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