scholarly journals Hydrogeochemical Characteristics and Genesis of Geothermal Water from the Ganzi Geothermal Field, Eastern Tibetan Plateau

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1631
Author(s):  
Fan ◽  
Pang ◽  
Liao ◽  
Tian ◽  
Hao ◽  
...  

The Ganzi geothermal field, located in the eastern sector of the Himalayan geothermal belt, is full of high-temperature surface manifestations. However, the geothermal potential has not been assessed so far. The hydrochemical and gas isotopic characteristics have been investigated in this study to determine the geochemical processes involved in the formation of the geothermal water. On the basis of δ18O and δD values, the geothermal waters originate from snow and glacier melt water. The water chemistry type is dominated by HCO3-Na, which is mainly derived from water-CO2-silicate interactions, as also indicated by the 87Sr/86Sr ratios (0.714098–0.716888). Based on Cl-enthalpy mixing model, the chloride concentration of the deep geothermal fluid is 37 mg/L, which is lower than that of the existing magmatic heat source area. The estimated reservoir temperature ranges from 180–210 °C. Carbon isotope data demonstrate that the CO2 mainly originates from marine limestone metamorphism, with a fraction of 74–86%. The helium isotope ratio is 0.17–0.39 Ra, indicating that the He mainly comes from atmospheric and crustal sources, and no more than 5% comes from a mantle source. According to this evidence, we propose that there is no magmatic heat source below the Ganzi geothermal field, making it a distinctive type of high-temperature geothermal system on the Tibetan Plateau.

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
X. Wang ◽  
G. L. Wang ◽  
H. N. Gan ◽  
Z. Liu ◽  
D. W. Nan

This study defines reasonable reservoir temperatures and cooling processes of subsurface geothermal fluids in the Chabu high-temperature geothermal system. This system lies in the south-central part of the Shenzha-Xietongmen hydrothermal active belt and develops an extensive sinter platform with various and intense hydrothermal manifestations. All the geothermal spring samples collected systematically from the sinter platform are divided into three groups by cluster analysis of major elements. Samples of group 1 and group 3 are distributed in the central part and northern periphery of the sinter platform, respectively, while samples of group 2 are scattered in the transitional zone between groups 1 and 3. The hydrochemical characteristics show that the geothermal waters of the research area have generally mixed with shallow cooler waters in reservoirs. The reasonable reservoir temperatures and the mixing processes of the subsurface geothermal fluids could be speculated by combining the hydrochemical characteristics of geothermal springs, calculated results of the chemical geothermometers, and silica-enthalpy mixing models. Contour maps are applied to measured emerging temperatures, mass flow rates, total dissolved solids of spring samples, and reasonable subsurface temperatures. They indicate that the major cooling processes of the subsurface geothermal fluids gradually transform from adiabatic boiling to conduction from the central part to the peripheral belt. The geothermal reservoir temperatures also show an increasing trend. The point with the highest reservoir temperature (256°C) appears in the east-central part of the research area, which might be the main up-flow zone. The cooling processes of the subsurface geothermal fluids in the research area can be shown on an enthalpy-chloride plot. The deep parent fluid for the Chabu geothermal field has a Cl− concentration of 290 mg/L and an enthalpy of 1550 J/g (with a water temperature of 369°C).


2013 ◽  
Vol 14 (4) ◽  
pp. 227-234 ◽  
Author(s):  
Xiangde Xu ◽  
Chungu Lu ◽  
Yihui Ding ◽  
Xiaohui Shi ◽  
Yudi Guo ◽  
...  

2015 ◽  
Vol 29 (1) ◽  
pp. 121-138 ◽  
Author(s):  
Xingwen Jiang ◽  
Yueqing Li ◽  
Song Yang ◽  
Kun Yang ◽  
Junwen Chen

Abstract The impacts of summer atmospheric heat source over the Tibetan Plateau (TP) on regional climate variation have attracted extensive attention. However, few studies have focused on possible causes of the interannual variation of atmospheric heat source over the TP. Total heat (TH) is generally composed of three components: surface sensible heat, latent heat release of condensation (LH), and radiative convergence. In this study, it is found that interannual variation of summer TH is dominated by LH in the central and eastern TP. The atmospheric circulation patterns associated with the TH over the TP in June are different from those in July and August. Large TH is accompanied by a cyclone centered over the South China Sea in June, which is replaced by an anticyclone in July and August. The interannual variation of July–August TH over the central and eastern TP is significantly affected by convection around the western Maritime Continent (WMC) that modulates the LH over the southeastern TP. Enhanced WMC convection induces an anticyclone to the south of the TP, which favors water vapor transport to the southeastern TP and thus an increase in precipitation. Enhanced convection over the southeastern TP may exert a positive feedback on local precipitation through pumping more water vapor from the southern boundary. Both observations and model simulations indicate that the enhanced WMC convection can induce the anticyclone to the south of the TP and convection–circulation is important for maintenance of the anticyclone.


2021 ◽  
Author(s):  
Alberto Ardid ◽  
Rosalind Archer ◽  
David Dempsey

<p>In high-temperature geothermal systems, understanding heat transfer helps conceptualize the whole system as well as estimating the resource size. To obtain the fullest picture, it is necessary to integrate different types of data, e.g., surface electromagnetic surveys, wellbore lithology, geochemistry, and temperature logs. This can be achieved through joint modelling. Here, we quantify the spatial distribution of heat transfer through the hydrothermally-altered, impermeable smectite layer that has developed atop the Wairākei-Tauhara geothermal system, New Zealand. Our approach involves first constraining 1D magnetotelluric (MT) inversion models with methylene blue analysis (MeB, an indicator of conductive smectite clay) and mapping these onto temperature and lithology data from geothermal wells. Then, one-dimensional models of heat transfer are fitted to well temperature logs to estimate heat flux variations across the field. We use our integrated method to estimate the average heat flux through the clay cap (2.2 W/m2) and total heat flow (380 ± 21 MW) of the Wairākei-Tauhara geothermal field. This approach models multiple datasets for estimating heat fluxes and could be applied in geothermal provinces around the world with implications for sustainable resource management and our understanding of magmatic systems.</p>


2021 ◽  
Author(s):  
Simon Védrine ◽  
Pascal Tarits ◽  
Mathieu Darnet ◽  
François Bretaudeau ◽  
Sophie Hautot

<p>Electromagnetic geophysical exploration plays a key role in high-temperature geothermal projects to estimate the geothermal potential of a region. The objective of an EM campaign applied to high-temperature geothermal exploration is to obtain an image of the impermeable clay cap, the permeable geothermal reservoir, and the system's heat source at depth, as these three components of the overall geothermal system have distinct electrical signatures. However, deep electromagnetic imaging in the coastal areas of volcanic islands represents a major challenge due to the presence of strong cultural noise induced by urbanized areas concentrated around the coast, the proximity to the sea, strong variations of topography and bathymetry, the small size of targets and the heterogeneity of the near surface. Our objective is the multi-scale integration of airborne transient electromagnetism (ATEM), shallow marine and in land magnetotelluric (MT) and controlled source electromagnetism (CSEM) to improve the reconstruction of deep geological structures by inversion. The contribution of the CSEM method is the key to overcoming cultural electromagnetic noise and exploiting data acquired in urbanized areas. In order to study how to integrate the different EM data, we first apply our methodology to data from a geothermal exploration campaign carried out a few years ago in Martinique in the French West Indies. Then, we present results from runs with synthetic tests for a campaign planned this year in Guadeloupe, also in the French West Indie, whose objective is to increase the production capacity of an existing geothermal field.</p>


2020 ◽  
Author(s):  
Yinglin Tian ◽  
Deyu Zhong

<p>The Tibetan Plateau (TP), known as the “World Roof”, has significant influences on hydrological and atmospheric circulation at both regional and global scale. As the Sanjiangyuan Region (SJY) supplies water resources to the adjacent river basin and the TP could exert strong thermal forcing on the atmosphere over Asian monsoon region, adequate understand of the climate change over this region and its underlying mechanisms is of great importance. Based on gridded data provided by China Meteorological Administration (CMA), a continuous warming trend higher than that over elsewhere in China has been observed over the TP during 1985-2014, especially in the cold season (0.69 K/decade) and over the SJY (1.0 K/decade). On the basis of ERA interim reanalysis datasets, this paper analyzed the factors facilitating this warming trend in the SJY from the perspective of energy transport. At first, the local processes involved were investigated by calculating partial temperature changes using the surface energy budget equation. Then the horizontal convection of heat was quantified by summing the heat flux across the boundaries of the SJY. Finally, a Lagrangian heat source diagnostic method was developed to identify the major heat source. As the results indicating, among all the local heat sources, the enhanced downward longwave radiation reflected to surface air and the increasing upward longwave radiation emitted by warmer land surface were responsible for the pronounced surface air warming. However, the changes in surface sensible and latent heat fluxes had a reduced warming effect on the surface air. As for the non-local horizontal heat sources, rising horizontal heat flux from the south, west and east boundaries into the SJY contributed to the higher surface temperature of the SJY. In winter season, the heat flows stemmed from the South Himalayan vein into the SJY played a dominant role. Moreover, the higher the temperature over the SJY was, the more inclined this heat source was to Nepal.</p>


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