Helium isotopes and heat flow on the ocean floor
- 標題
- Helium isotopes and heat flow on the ocean floor
- 作者
- Yuji Sano, Hiroshi Wakita
- 文件屬性
- 國外期刊
- 知識分類
- 基礎研究
- 出版年
- 1987
- 刊名
- Chemical Geology: Isotope Geoscience section
- 點閱數
- 2498
摘要
We have measured the View the MathML source and View the MathML source ratios of thirty-nine pore water and gas samples in deep-sea sediments collected at twelve sites on the Pacific Ocean bottom during the cruises of Deep Sea Drilling Project Legs 87, 89, 90 and 92. The View the MathML source and View the MathML source ratios vary from 2.15 · 10−7 to 1.65 and from 0.29 to 20, respectively. He · 10−6 in the sample is composed of four components: (1) atmospheric He dissolved in seawater; (2) atmospheric He with mantle-derived He in Pacific bottom water; (3) in situ radiogenic He in the sediment; and (4) crustal He in the basement rock. Assuming that the 20Ne contents are constant with the value of seawater, the depth variations in the View the MathML source ratios at five Sites, 583D, 594, 597A, 598A and 504B, may provide useful information on 4H flux at the ocean bottom. The estimated 4He fluxes vary from 0.2 · 104 to 4 · 104 atoms cm−2 s−1 and are one to three orders of magnitude less than those calculated from the excess He in deep ocean water. An overall similarity between the geographical distribution of the View the MathML source ratios and heat flow data is found in the study area, between the East Pacific Rise aross the Pacific Ocean and the Japanese Islands. The tendency is well explained by a conventional sea-floor spreading model.