Dissolution of the primordial rare gases into the molten Earth's material
Dissolution of the primordial rare gases into the molten Earth's material
复制标题
原始稀有气体溶解到熔融的地球物质中
DOI：
10.1016/0012-821x(80)90131-4
复制
发表时间：
1980
影响因子：
5.3
通讯作者：
C. Hayashi
中科院分区：
文献类型：
--
作者：
H. Mizuno;K. Nakazawa;C. Hayashi
我们在之前的论文中已经证明，如果地球形成时就存在原始太阳星云，那么地球曾经被稠密而巨大的原始大气包围，其底部的温度和压力分别约为4000 K和900 atm。我们推测，这种富含氢的大气层是在太阳星云本身消失后从地球逸出的，这两种现象可能是由于强烈的太阳风和辐射的影响。利用我们之前和新的对原始大气结构的计算结果，我们研究了原始大气中所含的稀有气体溶解到熔融地球物质中的量。发现溶解的稀有气体的量强烈依赖于大气颗粒的不透明度，即细颗粒的数量。然而，它们的同位素比率和相对丰度与不透明度无关，并且大约等于原始太阳星云中的同位素比率和相对丰度，即当前的太阳值。特别是，溶解的氖预计仍保留在目前的地幔中。因此，如果在现在的地幔物质中发现大量同位素比值接近太阳的氖，这将为原地球曾经被原始大气包围的主张提供直接证据。
We have shown in a previous paper that, if the primordial solar nebula existed when the Earth was formed, the Earth was once surrounded by a dense and massive primordial atmosphere, whose temperature and pressure were about 4000 K and 900 atm, respectively, at the bottom. We suppose that this hydrogen-rich atmosphere escaped from the Earth after the solar nebula itself disappeared, both phenomena probably being due to the effect of strong solar wind and radiation.Using the results of our previous and new calculations on the structure of the primordial atmosphere, we have investigated the amount of dissolution of the rare gases, which were contained in the primordial atmosphere, into the molten Earth's material.The amount of the dissolved rare gases is found to be strongly dependent on the grain opacity of the atmosphere, i.e., on the amount of fine grains. However, their isotopic ratios and relative abundance are independent of the opacity and approximately equal to those in the primordial solar nebula, that is, to the present solar values. Especially, the dissolved neon is expected to have remained in the present mantle. Therefore, if a considerable amount of neon with nearly the solar isotopic ratio is discovered in present mantle material, this offers direct evidence for the proposition that the proto-Earth was once surrounded by the primordial atmosphere.