Noble gas loss may indicate groundwater flow across flow barriers in southern Nevada
Noble gas loss may indicate groundwater flow across flow barriers in southern Nevada
复制标题
稀有气体损失可能表明地下水流穿过内华达州南部的流动屏障
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
J. Clark
中科院分区：
文献类型：
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作者：
James M. Thomas;B. Hudson;M. Stute;J. Clark
抽象的。在内华达州南部碳酸盐岩含水层中，从补给区到排泄区，地下水中惰性气体的平均计算温度从10 °C升高到22 °C。在流动障碍物处，这些区域流动系统中的地下水中的惰性气体损失可能是导致补给惰性气体温度升高的过程。低渗透性岩石嵌入高渗透性含水层岩石和低渗透性剪切带的存在将含水层厚度从数千米减小到数十米。在这些流动障碍物处，比平均补给高度低1 000多米，惰性气体通过夹杂在障碍物附近形成的气泡中从地下水中逸出，因为流体静压力大大降低。然而，在低海拔泉水排泄区，在区域流动系统的终点，不能排除地下水中的惰性气体与大气的再平衡。分子扩散不是从碳酸盐岩含水层的地下水中去除稀有气体的重要过程，因为浓度梯度很小。
Abstract. Average calculated noble gas temperatures increase from 10 to 22 °C in groundwater from recharge to discharge areas in carbonate-rock aquifers of southern Nevada. Loss of noble gases from groundwater in these regional flow systems at flow barriers is the likely process that produces an increase in recharge noble gas temperatures. Emplacement of low permeability rock into high permeability aquifer rock and the presence of low permeability shear zones reduce aquifer thickness from thousands to tens of meters. At these flow barriers, which are more than 1,000 m lower than the average recharge altitude, noble gases exsolve from the groundwater by inclusion in gas bubbles formed near the barriers because of greatly reduced hydrostatic pressure. However, re-equilibration of noble gases in the groundwater with atmospheric air at the low altitude spring discharge area, at the terminus of the regional flow system, cannot be ruled out. Molecular diffusion is not an important process for removing noble gases from groundwater in the carbonate-rock aquifers because concentration gradients are small.