scholarly journals Deep Groundwater Circulation through Gas Shales in Mountain Belts

2017 ◽  
Vol 17 ◽  
pp. 532-533 ◽  
Author(s):  
Stephen Grasby ◽  
Grant Ferguson ◽  
Alyson Brady ◽  
Christine Sharp ◽  
Peter Dunfield ◽  
...  
2012 ◽  
Vol 44 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Tomasz Olichwer ◽  
Robert Tarka ◽  
Magdalena Modelska

Chemical composition of groundwaters was investigated in the region of the Hornsund fjord (southern Spitsbergen). The investigations were conducted during polar expeditions organized by the University of Wroclaw in two summer seasons of 2003 and 2006. Three zones of groundwater circulation: suprapermafrost, intrapermafrost and subpermafrost, were identified in areas of perennial permafrost in the region of Hornsund. The zone of shallow circulation occurs in non-glaciated (suprapermafrost) and subglacial areas. In this zone, the chemical composition of groundwater originates from initial chemical composition of precipitation, mineralogical composition of bedrock, oxidation of sulphides and dissolution of carbonates. The intermediate system of circulation is connected with water flow inside and below perennial permafrost (intrapermafrost and subpermafrost). In this zone, the chemical composition of groundwater is mainly controlled by dissolution of carbonates, ion exchange processes involving Ca2+ substitution by Na+, and oxidation of sulphides under oxygen-depleted conditions. The subpermafrost zone (deep groundwater circulation) occurs in deep-tectonic fractures, which are likely conduits for the descent of shallow groundwater to deeper depths. In this zone, the groundwater shows lower mineralization comparing to intrapermafrost zone and has a multi-ion nature Cl–HCO3–Na-Ca–Mg.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yanlong Kong ◽  
Zhonghe Pang ◽  
Jumei Pang ◽  
Jie Li ◽  
Min Lyu ◽  
...  

A new significant aspect in the utilization of hydrothermal energy in China is the large-scale exploitation using multiwells from a single geothermal site. This requires detailed hydrogeochemical investigations to gain insight about deep groundwater circulation. At the Xiongxian karst geothermal site in North China, where the demonstration project of large-scale utilization was conducted, 40 boreholes with depths from 1000 to 1800 m were drilled in a region of 50 km2. A total of 25 water samples were collected, and temperature loggings were conducted in 16 of these wells. At the site scale, the hydraulic head was observed to decline from SW to NE, i.e., orthogonal to that at the regional scale. Moreover, the geothermal groundwater temperature, borehole temperature gradient, and heat flow in the caprock all exhibited the same spatial trend with the groundwater head. Based on the hydrogeochemical and temperature logging data, this was explained by mixing of lateral recharging groundwater with ascending thermal fluids through the Xiongxian Fault, after excluding the causes of pumping activities and geologic structure. In addition, geothermal groundwater 81Kr age was estimated to be approximately 760 k yr, which is much older than the 14C age of 20 to 30 k yr. The older 81Kr age implies a low renewability of deep groundwater circulation, which should be considered in terms of sustainable management in relation to the large-scale utilization of geothermal resources.


2016 ◽  
Vol 68 ◽  
pp. 10-18 ◽  
Author(s):  
S.E. Grasby ◽  
G. Ferguson ◽  
A. Brady ◽  
C. Sharp ◽  
P. Dunfield ◽  
...  

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 902-918 ◽  
Author(s):  
Martin Stute ◽  
Jozsef Deak

We have studied environmental isotopes and noble gases in groundwater samples from various locations in the Great Hungarian Plain along two selected hydrogeological cross-sections of ca 100km. The 14C groundwater ages were corrected hydrochemically and compared with age information derived from excess helium due to 4He from α-decay of U and Th and their daughter nuclides within the aquifer and to He accumulation from the crustal (and mantle) He flux. In correcting the 14C groundwater ages, we considered carbonate dissolution under open and closed system conditions in the infiltration areas. Non-radioactive reduction of the 14C/12C isotope ratio also plays an important role due to the addition of “dead” carbon species to groundwater along its subsurface pathway. High (corrected) 14C ages, which fall into the last global cold period, are supported by significantly lower heavy stable isotope values as well as lower temperatures derived from the noble gases Ne, Ar, Kr and Xe.


2012 ◽  
Vol 518-523 ◽  
pp. 4293-4298
Author(s):  
Dong Wang ◽  
Xiao Si Su ◽  
Guang Cai Hou ◽  
Zhen Hong Zhao ◽  
Hong Yun Ma

The hydrological cycling of groundwater in Ordos Cretaceous Basin show obvious stratification, the cycle can be divided into three layers by cycling depth, the shallow, the intermediate and the deep. In this paper, a classification standard formed with geochemical and isotopic information is described. The standard is based on a large number of borehole investigation and stratified sampling. In the shallow layer, the groundwater mostly is fresh water with lower amount of total dissolved solids, the dominated anion is HCO3,tritium and14C features show a high or rich properties; in the intermediate layer, the geochemical type of groundwater are SO4or SO4-Cl, the age of groundwater calculated by14C is less than 5000a; in the deep groundwater cycling, dominated anion show a complete evolution processes along the flow direction (HCO3-SO4-Cl) from recharge to discharge area, the groundwater age is commonly bigger than 5000a and even bigger than 10000a in the discharge area.


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3310
Author(s):  
Yuqing Zhao ◽  
You-Kuan Zhang ◽  
Yonglin Yang ◽  
Feifei Li ◽  
Sa Xiao

Water samples from rainfall, river, springs, and wells in the Xianshui River fault region near Xialatuo, China were collected during two sampling campaigns to investigate the complex groundwater circulation in the region. The major ions, stable isotopes, and four natural radium isotopes of the water samples were analyzed, and the results were utilized to identify different groundwater circulation depths. Most water samples excluding the one at a hot spring and the one at a borehole possess similar hydrochemical compositions and lower total dissolved solids (TDS), implying that their circulation depth is relatively shallow or that residence time is short. The sample at the hot spring has high TDS and high temperature as well as the high F concentration, inferring that it may circulate at a deeper depth. The sample at the borehole contains mixed hydrochemical characteristics of other samples. Three groundwater flow systems may exist in the study area: the shallow groundwater system recharged by precipitations and local groundwater flow, the deep groundwater system recharged by the regional groundwater flow, and the intermediate one between the above two systems. The finding of the three flow systems is supported by the δ2H and δ18O as well as the apparent radium ages of the samples. The δ2H and δ18O values at the intercept of the line formed by the shallow groundwater samples and the local meteoric water line (LMWL) are similar to those of modern precipitations. The δ2H and δ18O values at the intercept of the line formed by the deep groundwater samples and the LMWL show that it is probably recharged by relatively older precipitations. The 2H and 18O values of the borehole samples are between the above two intercept points. The deep-circulated groundwater with high temperature has longer apparent radium age than other water samples. The apparent radium ages of the shallow groundwater are similar but less than that of the deep groundwater. Groundwater at the borehole may circulate at a depth between the above two. The results of this study improve our understanding of the complex groundwater circulation and enable us to better protect and manage the groundwater resources in the region.


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