Oxygen and Hydrogen Isotopes of Waters in the Ordos Basin,China: Implications for Recharge of Ground

• 作 者: YANG Yuncheng SHEN Zhaoli WENG
• 机 构: Institute of Mineral Resources,Xi'an Institute of Geology and Mineral Resources,China University of
• 出 处: 地质学报（英文版）
• 发表日期: 2004年期
• 关键词: groundwater lake water oxygen and hydrogen isotopes precipitation Ordos Basin

Hundreds of precipitation samples collected from meteorological stations in the Ordos Basin from January 1988 to December 2005 were used to set up a local meteoric water line and to calculate weighted average isotopic compositions of modern precipitation.Oxygen and hydrogen isotopes, with and gradually decrease in summer and fall,illustrating that the seasonal effect is considerable.They also show that the isotopic difference between south portion and north portion of the Ordos Basin are not obvious.and the isotope in the middle portion iS normally depleted.The isotope compositions of 32 samples collected from shallow groundwater(less than a depth of 150 m)in desert plateau range from for JD.Most of them are identical with modern precipitation.The isotope compositions of 22 middle and deep groundwaters(greater than a depth of 275 m)fall in ranges from-11.6‰to-8.8‰with an average of-10.2‰ for ￡18O and from-89‰ to-63‰ with an average of-76‰ for ￡D.The average values are significantly less than those of modern precipitation,illustrating that the middle and deep groundwaters were recharged at comparatively lower air temperatures.Primary analysis of 14C shows that the recharge of the middle and deep groundwaters started at late Pleistocene.The isotopes of 13 lake water samples collected from eight lakes define a local evaporation trend,with a relatively flat slope of 3.77,and show that the lake waters were mainly fed by modern precipitation and shallow groundwater.