Chlorine 36 dating of very old groundwater: 2. Milk River Aquifer, Alberta, Canada
Chlorine 36 dating of very old groundwater: 2. Milk River Aquifer, Alberta, Canada
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非常古老的地下水的氯 36 测年：2. 米尔克河含水层，艾伯塔省，加拿大
DOI：
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
G. Swanick
中科院分区：
文献类型：
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作者：
F. Phillips;H. Bentley;S. Davis;D. Elmore;G. Swanick
加拿大阿尔伯塔省南部的米尔克河含水层由厚页岩单元之间夹层的砂岩组成。地下水被限制并通过页岩向上和向下渗漏排出。 Cl− 的浓度通过含水层下降约 2 个数量级。 Cl−的增加使系统的 36Cl 测年变得复杂。气候变化、原生水冲刷、从含水层以下较旧的水中引入Cl−以及离子过滤已被认为是增加的可能解释。 36Cl 数据显示 36Cl/Cl 比率下降梯度持续下降，但含水层某些部分的 36Cl 浓度下降梯度有所增加。根据 36Cl/Cl 比率计算的日期显示了根据系统上的液压控制的合理分布，而根据 36Cl 浓度计算的日期给出了负年龄。这表明离子过滤是 Cl− 增加的原因，并且 36Cl/Cl 数据是首选。我们估计水龄超过 2 m.y。靠近含水层的远端。
The Milk River aquifer in southern Alberta, Canada, consists of sandstone interbedded between thick shale units. The groundwater is confined and discharges by both upward and downward leakage through the shales. The concentration of Cl− increases by about 2 orders of magnitude downgradient through the aquifer. This Cl−increase complicates 36Cl dating of the system. Climatic changes, flushing of connate water, introduction of Cl− from older water below the aquifer, and ion filtration have been proposed as possible explanations for the increase. The 36Cl data show a consistent decrease of the 36Cl/Cl ratio downgradient, but an increase in the 36Cl concentration downgradient in certain parts of the aquifer. Dates calculated from the 36Cl/Cl ratio show a reasonable distribution in light of the hydraulic controls on the system, whereas dates calculated from the 36Cl concentration give negative ages. This suggests that ion filtration is responsible for the Cl− increase and that the 36Cl/Cl dates are to be preferred. We estimate water ages to be more than 2 m.y. near the distal end of the aquifer.