OXYGEN ISOTOPE EXCHANGE-RATE BETWEEN DISSOLVED SULFATE AND WATER AT HYDROTHERMAL TEMPERATURES
OXYGEN ISOTOPE EXCHANGE-RATE BETWEEN DISSOLVED SULFATE AND WATER AT HYDROTHERMAL TEMPERATURES
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DOI：
10.1016/0016-7037(85)90314-x
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发表时间：
1985-01-01
影响因子：
5
通讯作者：
SAKAI, H
中科院分区：
文献类型：
--
作者：
CHIBA, H;SAKAI, H
溶解的硫酸盐和水之间的氧同位素交换速率在100 ℃下实验测定，200.degree. 300度。C.同位素交换速率强烈依赖于溶液的温度和pH。结合反应速率的温度和pH依赖性，估计交换反应相对于硫酸根为1级。在给定温度下交换反应的表观速率常数的对数是在实验温度下计算的pH的函数。从表观速率常数的pH依赖性，推断溶解硫酸盐和水之间的同位素交换反应进行通过碰撞之间的H2SO 40和H2O在低pH值，和HSO 4-和H2O在中间pH值之间的同位素交换速率得到的氧同位素地质测温利用所研究的同位素交换是适用于热储温度估计。该反应对海洋温度的外推半衰期为109年，这意味着海洋硫酸盐和水之间的交换不能控制海洋硫酸盐的氧同位素比值。
Oxygen isotope exchange rate between dissolved sulfate and water was experimentally determined at 100.degree., 200.degree. and 300.degree. C. The isotope exchange rate is strongly dependent on temperature and pH of the solution. Combining the temperature and pH dependence of the reaction rate, the exchange reaction was estimated to be 1st-order with respect to sulfate. The logarithm of apparent rate constant of exchange reaction at a given tmperature is a function of the pH calculated at the experimental temperatures. From the pH dependence of the apparent rate constant, it was deduced that the isotope exchange reaction between dissolved sulfate and water proceeds through collision between H2SO40 and H2O at low pH, and between HSO4- and H2O at intermediate pH. The isotope exchange rate obtained indicates that oxygen isotope geothermometry utilizing the studied isotope exchange is suitable for temperature estimation of geothermal reservoirs. The extrapolated half-life of this reaction to oceanic temperature is .apprx. 109 yr, implying that exchange between oceanic sulfate and water cannot control the oxygen isotope ratio of oceanic sulfates.