Groundwater recharge history and hydrogeochemical evolution in the Minqin Basin, North West China

被引:231
作者
Edmunds, W. M.
Ma, Jinzhu
Aeschbach-Hertig, W.
Kipfer, R.
Darbyshire, D. P. F.
机构
[1] Univ Oxford, Oxford Ctr Water Res, Ctr Environm, Oxford OX1 3QY, England
[2] Lanzhou Univ, Minist Educ, CAEP, Key Lab W Chinas Environm Syst, Lanzhou 730000, Peoples R China
[3] Heidelberg Univ, Inst Umweltphys, D-69120 Heidelberg, Germany
[4] ETH, CH-8092 Zurich, Switzerland
[5] NERC, Isotope Geosci Lab, Keyworth NG12 5GG, Notts, England
基金
中国国家自然科学基金;
关键词
D O I
10.1016/j.apgeochem.2006.07.016
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
The Minqin Basin is a type area for examining stress on groundwater resources in the Gobi Desert, and has been investigated here using a combination of isotopic, noble gas and chemical indicators. The basin is composed of clastic sediments of widely differing grain size and during the past half century over 10000 boreholes have been drilled with a groundwater decline of around 1 ma(-1). Modern diffuse recharge is unlikely to exceed 3 mm a(-1), as determined using unsaturated zone profiles and Cl- mass balance. A small component of modern (< 50 a) groundwater is identified in parts of the basin from H-3-(3) He data, probably from irrigation returns. A clear distinction is found between modern waters with median 6180 values of 6.5 +/- 0.5%. and most groundwaters in the basin with more depleted isotopic signatures. Radiocarbon values as pmc range from 0.6% to 85% modern, but it is difficult to assign absolute ages to these, although a value of 20% modern C probably represents the late Pleistocene to Holocene transition. The delta C-13 compositions remain near-constant throughout the basin (median value of -8.1 parts per thousand delta C-13) and indicate that carbonate reactions are unimportant and also that little reaction takes place. There is a smooth decrease in 14 C activity accompanied by a parallel increase in He-4 accumulations from S-N across the basin, which define the occurrence of a regional flow system. Noble gas temperatures indicate recharge temperatures of about 5.6 degrees C for late Pleistocene samples, which is some 2-3 degrees C cooler than the modern mean annual air temperature and the recharge temperature obtained from several Holocene samples. Groundwaters in the Minqin Basin have salinities generally below 1 g/L and are aerobic, containing low Fe but elevated concentrations of U, Cr and Se (mean values of 27.5, 5.8 and 5.3 mu g L-1, respectively). Nitrate is present at baseline concentrations of around 2 mg L-1 but there is little evidence of impact of high NO3 from irrigation returns. Strontium isotope and major ion ratios suggest that silicate reactions predominate in the aquifer. The results have important implications for groundwater management in the Minqin and other water-stressed basins in NW China - a region so far destined for rapid development. The large proportion of the water being used at present is in effect being mined and significant changes are urgently needed in water use strategy. (c) 2006 Elsevier Ltd. All rights reserved.
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收藏
页码:2148 / 2170
页数:23
相关论文
共 39 条
[1]   Interpretation of dissolved atmospheric noble gases in natural waters [J].
Aeschbach-Hertig, W ;
Peeters, F ;
Beyerle, U ;
Kipfer, R .
WATER RESOURCES RESEARCH, 1999, 35 (09) :2779-2792
[2]   Palaeotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air [J].
Aeschbach-Hertig, W ;
Peeters, F ;
Beyerle, U ;
Kipfer, R .
NATURE, 2000, 405 (6790) :1040-1044
[3]  
[Anonymous], ENV TRACERS SUBSURFA
[4]  
[Anonymous], 1991, ASSESSMENT GROUNDWAT
[5]   Provenance of the north Pacific sediments and process of source material transport as derived from Rb-Sr isotopic systematics [J].
Asahara, Y ;
Tanaka, T ;
Kamioka, H ;
Nishimura, A ;
Yamazaki, T .
CHEMICAL GEOLOGY, 1999, 158 (3-4) :271-291
[6]   A mass spectrometric system for the analysis of noble gases and tritium from water samples [J].
Beyerle, U ;
Aeschbach-Hertig, W ;
Imboden, DM ;
Baur, H ;
Graf, T ;
Kipfer, R .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 2000, 34 (10) :2042-2050
[7]   Evidence for periods of wetter and cooler climate in the Sahel between 6 and 40 kyr BP derived from groundwater [J].
Beyerle, U ;
Rueedi, J ;
Leuenberger, M ;
Aeschbach-Hertig, W ;
Peeters, F ;
Kipfer, R ;
Dodo, A .
GEOPHYSICAL RESEARCH LETTERS, 2003, 30 (04)
[8]   A mid-Holocene drought interval as evidenced by lake desiccation in the Alashan Plateau, Inner Mongolia, China [J].
Chen, FH ;
Wu, W ;
Holmes, JA ;
Madsen, DB ;
Zhu, Y ;
Jin, M ;
Oviatt, CG .
CHINESE SCIENCE BULLETIN, 2003, 48 (14) :1401-1410
[9]  
CHEN L, 1982, J DESERT RES, V2, P6
[10]  
CHEN L, 1992, WATER LAND RESOURCES, P143