scholarly journals Noble gas geochemistry and chronology of groundwater in an active rift basin in central China

2019 ◽  
Vol 98 ◽  
pp. 01040 ◽  
Author(s):  
Zhonghe Pang ◽  
Jie Li ◽  
Jiao Tian
Keyword(s):  
Groundwater Recharge ◽  
Noble Gas ◽  
Sedimentary Basins ◽  
Central China ◽  
Rift Basin ◽  
Rock Interaction ◽  
Groundwater Circulation ◽  
History Of ◽  
Circulation Dynamics ◽  
Water Rock Interaction

Stable noble gas isotopes are excellent groundwater tracers. Radioactive noble gases are emerging new tools in the study of groundwater circulation dynamics. Among these, the 85Kr and 81Kr, and 39Ar have advanced very fast in recent years and exhibit strong potential in the reconstruction of the history of groundwater recharge and evolution in sedimentary basins at different scales. Here, we report the findings in groundwater circulation dynamics as relative to intensive water-rock interactions, heat transfer and He gas flux in Guanzhong Basin located in Xi’an, the geographical centre of China, which is a rift basin created by collision between the Eurasia and Indian plates, with active neotectonic activities. The recent technological breakthrough in noble gas isotope measurements, i.e. the atomic trap trace analysis (ATTA) techniques on Kr and Ar gas radionuclei, has revolutionized groundwater dating. Noble gas samples from shallow and deep wells to 3000 m depth have been collected to study isotope variations to reconstruct the history of groundwater recharge and understand the water-rock interaction processes. Stable isotopes of water show strong water-rock interaction in the formation, creating a strong positive O-isotope shift up to 10 ‰, a phenomenon that is rarely seen in a fairly low temperature environment. Analysis of 85Kr and 81Kr show groundwater ages up to 1.3 million years old along both North-South and a West-East cross sections, which offers strong evidence about the slow moving flow, strong water-rock interaction, rich geothermal resources as well as He gas resources.

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 Mixing Experimental Study on Water-rock Interaction (WRI) in the Inland Shallow Salt Groundwater Area

2015 ◽  
Vol 9 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Li Changsuo ◽  
Xing Liting ◽  
Wang Liyan ◽  
Zhang Fengjuan ◽  
Liu Bo
Keyword(s):  
Salt Water ◽  
Atmospheric Precipitation ◽  
Shallow Groundwater ◽  
Mineral Dissolution ◽  
Rock Interaction ◽  
Groundwater Circulation ◽  
Exchange Adsorption ◽  
Action Process ◽  
Strong Evaporation ◽  
Water Rock Interaction

The shallow salt groundwater is widely distributed in North Shandong, which makes it difficult for people and livestock to drink daily. In addtion, the genetic mechanism of shallow salt groundwater is complicated. The study was carried out in Xiyan Village of Jiyang County, it choosed the silt buried in 3-9 m depth, shallow salt groundwater and atmospheric precipitation as test materials to measure chemical composition of groundwater. Base on soluble salt test, rain-saltwater mixing test and rain-saltwater-silt mixing test, ions component of mixture were measured, the hydrogeochemical action process of WRI was analyzed and formation-evolution of inland saltwater was deepened knowledge. It is shown that (1) The occurrence threshold of WRI was 20%, which was the volume of saltwater in mixture. (2) When the rainwater, saltwater and silt were mixed together for 12 hours, calcite and dolomite precipitated, halite and gypsum were in dissolved state. When the volume of saltwater in mixture was larger than 20%, gypsum was closed to saturation, the main cation exchange was Mg-Na, the exchange of Ca-Na was in the second place; The order for anion adsorption amount of aquifer medium was SO42- > HCO3- >C-. The study proves that groundwater circulation is slow and continual, some hydrochemical actions (i.e. ion exchange, adsorption, mineral dissolution or precipitation, and strong evaporation-concentration) are happened during the evolution process of inland shallow groundwater. All these will lead to Cl•SO4-Mg•Na type salt or slight salt water with TDS being larger than 2g·L-1.

Stable Isotope Measurements of Martian Atmospheric CO2 at the Phoenix Landing Site

Science ◽  
2010 ◽  
Vol 329 (5997) ◽  
pp. 1334-1337 ◽  
Author(s):  
Paul B. Niles ◽  
William V. Boynton ◽  
John H. Hoffman ◽  
Douglas W. Ming ◽  
Dave Hamara
Keyword(s):  
Landing Site ◽  
Primary Component ◽  
Rock Interaction ◽  
Volcanic Degassing ◽  
Carbonate Formation ◽  
Stable Isotopic ◽  
Pee Dee ◽  
History Of ◽  
Temperature Water ◽  
Water Rock Interaction

Carbon dioxide is a primary component of the martian atmosphere and reacts readily with water and silicate rocks. Thus, the stable isotopic composition of CO2 can reveal much about the history of volatiles on the planet. The Mars Phoenix spacecraft measurements of carbon isotopes [referenced to the Vienna Pee Dee belemnite (VPDB)] [δ13CVPDB = –2.5 ± 4.3 per mil (‰)] and oxygen isotopes [referenced to the Vienna standard mean ocean water (VSMOW)] (δ18OVSMOW = 31.0 ± 5.7‰), reported here, indicate that CO2 is heavily influenced by modern volcanic degassing and equilibration with liquid water. When combined with data from the martian meteorites, a general model can be constructed that constrains the history of water, volcanism, atmospheric evolution, and weathering on Mars. This suggests that low-temperature water-rock interaction has been dominant throughout martian history, carbonate formation is active and ongoing, and recent volcanic degassing has played a substantial role in the composition of the modern atmosphere.

scholarly journals Geothermometry and Circulation Behavior of the Hot Springs in Yunlong County of Yunnan in Southwest China

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiaocui Wang ◽  
Xun Zhou
Keyword(s):  
Southwest China ◽  
Hot Springs ◽  
Cold Water ◽  
Geothermal Reservoir ◽  
Spring Discharge ◽  
Geochemical Processes ◽  
Rock Interaction ◽  
Thermal Groundwater ◽  
Groundwater Circulation ◽  
Water Rock Interaction

Travertine and nontravertine thermal springs have been studied in Yunlong County in southwest China to determine the geothermal reservoir temperatures and to find the geochemical processes that affect the evolution of thermal groundwater constituents during subsurface circulation. Hydrochemical characteristics distinguish travertine from nontravertine types. Travertine springs show HCO3·Cl-Na and SO4·HCO3-Ca·Na type, and a nontravertine spring presents Cl·HCO3·SO4-Na type. Log(Q/K) versus T diagrams show that reservoir temperatures can be expressed as intervals based on the equilibrium mineral assemblages coexisting in equilibrium and multiminerals in equilibrium with the aid of the PHREEQC and WATCH programs. The spring water mixing ratio with shallow water is between 59% and 82% with steam loss ranging from 12.1% to 27.8%. The Dalang Spring mixes with the highest proportion of cold water (76% to 82%) among the four hot springs and has the highest geothermal reservoir temperature (132°C to 176.9°C). The water-rock interaction during recharge from precipitation demonstrates that the minerals halite, kaolinite, chalcedony, plagioclase, and CO2(g) play an important part in the evolution of the thermal groundwater. Four inverse modeling simulation paths between precipitation and spring discharge were established to calculate the mass flux of minerals by the PHREEQC program. Halite, kaolinite, chalcedony, plagioclase, and CO2(g) participate in dissolution reactions in the thermal groundwater circulation, while gypsum, calcite, dolomite, biotite, and fluorite keep the geochemical processes in equilibrium.

scholarly journals Research on Formation Mechanism of Jiyang Shallow Saline Ground Water

2015 ◽  
Vol 9 (1) ◽  
pp. 155-160
Author(s):  
Zhang Fengjuan ◽  
Xing Liting ◽  
Wang Song ◽  
Zhuang Huibo ◽  
Dou Tongwen ◽  
...  
Keyword(s):  
Saline Water ◽  
Salt Water ◽  
Clay Content ◽  
Water Area ◽  
Test Methods ◽  
Rock Interaction ◽  
Tracing Test ◽  
Groundwater Circulation ◽  
Water Rock Interaction

Shallow salt water in the inland plain has huge development potential. Taking saline water area in Sungeng Town, Jiyang County as an example, based on field water quality and water table tests., tracing test, methods such as mathematical statistical, hydrochemistry diagram of piper and numerical simulation by PHREEQC are used to analyze synthetically. 6862 groups data were studied. Results showed: (1) The groundwater presents typically “weather - evaporation” type, chemistry type is Cl.SO4-Mg.Na. and Cl.SO4-Na.Mg type. (2) In area of inland saline water presents characteristics of lagging water flow with high clay content in aquifer medium. Groundwater mineralization is obvious. (3) Hydrogeochemistry actions such as evaporation, alternate adsorption and water-rock interaction are the primary cause of the forming complex hydrochemistry type. The unique groundwater circulation characteristics of inland plains saltwater area makes water dynamic being relatively stable.

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