Thermal stability and closure temperature of barite for electron spin resonance dating
Thermal stability and closure temperature of barite for electron spin resonance dating
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DOI：
10.1016/j.quageo.2022.101332
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发表时间：
2022-05-10
影响因子：
2.7
通讯作者：
Yamamoto, Yuzuru
中科院分区：
文献类型：
--
作者：
Tsang, Man-Yin;Toyoda, Shin;Yamamoto, Yuzuru
电子自旋共振（ESR）测年已应用于热液喷口重晶石。热液喷口中的重晶石在形成后迅速冷却，因此很少有人关注重晶石ESR信号的热稳定性。为了辨别流体流动的多个事件或在其他地质环境中确定重晶石的日期，必须知道ESR强度如何随热衰减，特征衰减时间和闭合温度。在这项研究中，我们证明了在重晶石中的SO 3-自由基的ESR强度的衰减是一个二级反应。ESR强度在100 ℃、200 ℃、300 ℃和500 ℃时下降一半的特征衰减时间分别为106年、10年、10小时和1秒的数量级。重晶石的闭合温度一般在190 ~ 340 ℃之间。这些结果为重晶石ESR强度稳定的环境和ESR年龄可消除的条件提供了必要的信息。
Electron spin resonance (ESR) dating has been applied to barite from hydrothermal vents. Barite in hydrothermal vents cools down rapidly after formation so little attention was paid to the thermal stability of the ESR signal of barite for dating. To discern multiple episodes of fluid flow or to date barite in other geological settings, it is essential to know how the ESR intensity decays with heat, the characteristic decay time and the closure temperature. In this study, we demonstrate that the decay of the ESR intensity of the SO3- radical in barite is a second-order reaction. The characteristic decay time for the ESR intensity to drop by half at 100 degrees C, 200 degrees C, 300 degrees C and 500 degrees C is of the order of magnitude of 106 years, 10 years, 10 h and 1 s respectively. The closure temperature of barite is generally between 190 and 340 degrees C. These results provide essential information on environments where the ESR intensity in barite is stable and conditions under which ESR ages can be erased.