地球内部的^(3)He是原始起源吗?

Does ^3He in the Interior of the Earth is of ＂Primordial Origin＂？

3He的来源至今被地球学家解释为在46亿年前地球形成时贮存在地球内部的,即原始起源。但是这原始起源学说在解释有的地学问题已受到了挑战,例如:①有的金刚石中的反常高的3He/4He比值;②大洋中脊玄武岩(MORB)和洋中脊的热液气孔喷出的热流的3He/4He比值具有近似恒定的峰状分布。作者最近对火山湖水中氚的垂直分布进行了新的研究,发现火山口形成的土耳其Nemrut湖和德国Laacher湖底部同时注入有来自地幔的氚(3H)和3He。这二者都是核聚变(d-d反应)的产物。氚的半衰期为12.4年,地球形成时的氚早已不存在。地球深处由已知的常规核反应生产的氚含量小于0.01TU(1TU相当3H/H=10-18),处于探测限以下。地球深处释放的氚表明其可能来源于核聚变。作者认为产生3H和3He的核聚变可能发生在地幔和地核的交界处的高温高压下富集氢的介质。由此推论:地球深处的3He并非一定是“原始起源”。

The origin of ^3 He has been assumed to be of primordial origin, trapped within the Earth at the time that the Earth formed 4, 6 billion years ago. However, the obstacles for hypothesis of primordial origin of ^3 He have been met in explanation of ^3 He paradoxes in the Earth, for example, ①extremely high ^3 He/^4 He ratios in the diamonds and ②narrow distribution of ^3 He/^4 He in mid-ocean ridge basalts （MORB） and the hydrothermal vent fluids at mid-ocean ridge （MOR）. Author have made a new investigation on the vertical profiles of tritium concentration in the crater lakes and found that both ^3 He and ^3 H released from Earth-mantle were injected at the bottoms of Lakes Nemrut （Turkey） and Laacher （Germany）. Both ^3 H and ^3 He are the products of nuclear fusion （d-d reaction）. Tritium has a half-life of 12.4 years. The primordial tritium formed in the Earth 4.6 billion years ago already decayed to a negligible level in the Earth history. ^3 H concentration from any known nuclear reactions has been estimated to be less than 0.01 TU （1 TU means ^3H/H= 10^18）,below detection limit. Author conclude that the d-d reaction might be induced near （in） the Earth core where are of hydrogen-bearing minerals and rich U and Th at high temperature and high pressure.