scholarly journals Genesis of the Xifeng Low-Temperature Geothermal Field, Guizhou, SW China: Constrains From Geology, Element Geochemistry, and D-O Isotopes

2021 ◽  
Vol 9 ◽  
Author(s):  
Yanyan Li ◽  
Ji Dor ◽  
Chengjiang Zhang ◽  
Guiling Wang ◽  
Baojian Zhang ◽  
...  

The Xifeng geothermal field is located in the Yangtze Craton, SW China, and is one of the most representative low-temperature geothermal fields in China. Widespread thermal anomalies, hot springs, and geothermal wells have been reported by previous studies. However, the nature and forming mechanisms of the field remain poorly understood. Element geochemical (ions, rare earth elements) and stable isotopic (D, O) composition of hot springs, geothermal fluids, rivers, and cold springs from different locations of the Xifeng geothermal field were analyzed in this study. The ions studies revealed that most samples featured the Ca-Mg-HCO3 type, except Xifeng hot springs, and which were characterized by the Ca-Mg-HCO3-SO4 type. Based on quartz geothermometers, the estimated reservoir temperature was 77°C. The results of stable isotopes (D, O) manifest that the Xifeng geothermal system was recharged by meteoric water at an elevation of 1,583 m from SW to NE. The research of rare earth elements (REE) revealed that their accumulation characteristics and obvious positive Eu anomaly were inherited from host feldspar-bearing reservoir dolomites through water-rock interactions. Combined with these observations, geological setting, and previous studies, it was concluded that the formation of the Xifeng geothermal field resulted from recharge, deep circulation, and secondary rising of the meteoric water along the faults. First, meteoric water infiltrated to depth through faults and crack zones. Second, the deep-infiltrated water was heated by radioactive heat, deep heat, and tectonic frictional heat. Finally, as the warmed-up waters underwent considerable deep circulation in the reservoir, it rose again along the main faults, and mixed with groundwater near the surface. Taken together, we suggest that the Xifeng geothermal system should be assigned as a faults-controlling, and deeply circulating meteoric water of low-temperature category.

1979 ◽  
Vol 18 (4) ◽  
pp. 385-394
Author(s):  
J. Urrutia Fucugauchi

El presente trabajo se basa en resultados de elementos de tierras raras obtenidas en basaltos toleíticos provenientes de la boca del Golfo de California, México. Los basaltos fueron muestreados durante una operación de dragado en la latitud de 23° N.Los elementos de tierras raras fueron obtenidos por el método instrumental de activación por neutrones (López et al.. 1978). Las muestras fueron tomadas entre la cresta de la Dorsal de Pacífico Este y la plataforma continental de la península de Baja California. Las edades asignadas a las muestras con base en datos de anomalías magnéticas y de la relación batimetría edad del fondo oceánico son de 0, 1.7 y 3.5 millones de años. Los datos son empleados en este trabajo para evaluar el comportamiento de las tierras raras durante procesos de alteración a bajas temperaturas. Fue usado un procedimiento de normalización propuesto por Ludden y Thompson (1978) para datos de basaltos en la dorsal del Atlántico Medio (23°N). No obstante que el valor de la normalización (esto es, la abundancia de Yb para basaltos sin alteración) puede no ser válido para los basaltos de la Dorsal de Pacífico Este (23°N), los resultados obtenidos son consistentes y reflejan los efectos de alteración. Dichos resultados están de acuerdo con el modelo propuesto por Ludden y Thompson. Las muestras reflejan un enriquecimiento progresivo de las tierras raras ligeras (La a Sm) con la alteración (edad). Por otro lado, las diferencias observadas con respecto a los resultados anteriores indican que las tierras raras no se comportaran se igual forma en todos los ambientes de alteración. En particular, el elemento Ce muestra anomalías positivas y negativas. El agua de mar tiene una anomalía negativa, de aquí que este comportamiento puede ser interpretado en términos de la abundancia de Ce en el agua de mar o bien su fraccionamiento del agua de mar.


2018 ◽  
Vol 37 (2) ◽  
pp. 626-645
Author(s):  
Wei Zhang ◽  
Guiling Wang ◽  
Linxiao Xing ◽  
Tingxin Li ◽  
Jiayi Zhao

The geochemical characteristics of geothermically heated water can reveal deep geothermal processes, leading to a better understanding of geothermal system genesis and providing guidance for improved development and utilization of such resources. Hydrochemical and hydrogen oxygen isotope analysis of two geothermal field (district) hot springs based on regional geothermal conditions revealed that the thermal water in the Litang region is primarily of the HCO3Na type. The positive correlations found between F−, Li2+, As+, and Cl− indicated a common origin, and the relatively high Na+ and metaboric acid concentrations suggested a relatively long groundwater recharge time and a slow flow rate. The values of δD and δ18O were well distributed along the local meteoric line, indicating a groundwater recharge essentially driven by precipitation. The thermal reservoir temperature (152°C–195°C) and thermal cycle depth (3156–4070 m) were calculated, and the cold water mixing ratio (60%–68%) was obtained using the silica-enthalpy model. Finally, hydrogeochemical pathway simulation was used to analyze the evolution of geothermal water in the region. The results were further supported by the high metasilicate content in the region. Of the geothermal fields in the region, it was found that the Kahui is primarily affected by albite, calcite precipitation, and silicate, while the Gezha field is primarily affected by calcite dissolution, dolomite precipitation, and silicate.


Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 392 ◽  
Author(s):  
Katarzyna Gros ◽  
Ewa Słaby ◽  
Petras Jokubauskas ◽  
Jiří Sláma ◽  
Gabriela Kozub-Budzyń

Allanite is one of the main rare earth elements (REE)-rich accessory minerals in composite dykes from the granitoid pluton of Karkonosze. These dykes differ in composition from the bulk of the pluton by elevated rare earth elements (REE), Y, Zr, and alkali contents, suggesting contribution of an additional component. Allanite exhibits complex alteration textures, which can be divided into two stages. The first stage is represented by allanite mantles, formed by fluid infiltration into previously crystallized magmatic allanite. These zones have low totals, are Ca-, Al-, Mg-, and light REE (LREE)-depleted, and Y-, heavy REE (HREE)-, Th-, Ti-, and alkali-enriched. The fractionation between LREE and HREE was caused by different mobility of complexes formed by these elements in aqueous fluids. The second stage includes recrystallized LREE-poor, Y-HREE-rich allanite with variable Ca, Al, Mg, and REE-fluorocarbonates. The alteration products from both stages demonstrate higher Fe3+/(Fe2+ + Fe3+) ratios and a negative Ce anomaly. These features point to the alkaline, low-temperature, and oxidized nature of the fluids. The differences in mobility and solubility of respective ligands show that the fluids from the first stage may have been dominated by Cl, whereas those of the second stage may have been dominated by F and CO2 (and PO4 in case of one sample). The inferred chemistry of the fluids resembles the overall geochemical signature of the composite dykes, indicating a major contribution of the hydrothermal processes to their geochemical evolution.


ChemSusChem ◽  
2010 ◽  
Vol 3 (12) ◽  
pp. 1379-1382 ◽  
Author(s):  
Xiaochun Zhou ◽  
Yunjie Huang ◽  
Changpeng Liu ◽  
Jianhui Liao ◽  
Tianhong Lu ◽  
...  

RSC Advances ◽  
2021 ◽  
Vol 11 (44) ◽  
pp. 27607-27619
Author(s):  
Na Li ◽  
Shenghan Zhang ◽  
Zedong Cheng ◽  
Wenfei Wu

The group has shown that Baiyun Ebo rare earth concentrate has excellent performance in NH3-SCR denitrification when used as a carrier, where rare earth elements are mainly present in cerium fluorocarbon ore (CeCO3F) and monazite (CePO4) mineral phases.


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