(Table 1) 3He/4He and 4He/20Ne ratios of pore gases in sediment at DSDP Sites 84-568 and 90-594

Studies on He isotope ratios of gas and rock samples in various parts of the world have shown a close relation between the 3He/4He ratio and geotectonic features of the sampling area. Emission of primordial He is commonly found in gases and fluid in Cenozoic volcanic areas (mid-ocean ridges, hot spots, and subduction zones), whereas that of radiogenic He is predominant in continental areas. Thus, the 3He/4He ratio is considered a useful tool for evaluating a variety of geotectonic environments.

全球各地气体与岩石样本的氦同位素比率研究表明，3He/4He比率与采样区域的大地构造特征存在密切关联。原始氦（primordial He）的排放常见于新生代火山区域（如洋中脊、热点及俯冲带）的气体与流体中，而放射性成因氦（radiogenic He）则在大陆区域占主导地位。因此，3He/4He比率被视为评估各类大地构造环境的有效工具。