地球内部の太陽タイプのネオンの起源について

概要

論文の詳細を見る
Recently, precise noble gas analyses of many types of mantle-derived materials have proved that isotopic composition of Ne in the Earths interior (mantle) is quite different from that of the Earths atmosphere (20Ne/22Ne=9.8), but much similar to the solar-type composition (20Ne/22Ne-13). This observation challenges the prevailing idea that the Earths atmosphere was simply derived from the Earths interior, because both the atmosphere and its source (=mantle) must have identical isotopic compositions. One possibility that can account for this observation is an extensive loss of the primordial atmosphere at an early stage of the Earths history. This model assumes a solar-type Ne both for the primordial atmosphere and the mantle, but later on, Ne in the primordial atmosphere became fractionated due to hydrodynamic escape of the atmosphere, which resulted in the “heavy” Ne isotopic composition of the present atmosphere. This paper reviews the discovery of the solar-type Ne in the Earths interior and discuss its importance in earth and planetary sciences.
日本質量分析学会の論文
1997-12-01