Distribution and sources of pre-anthropogenic lead isotopes in deep ocean water from FeMn crusts
- 標題
- Distribution and sources of pre-anthropogenic lead isotopes in deep ocean water from FeMn crusts
- 作者
- F. von Blanckenburg, R.K. O'nions, J.R. Heinz
- 文件屬性
- 國外期刊
- 知識分類
- 基礎研究
- 出版年
- 1996
- 刊名
- Geochimica et Cosmochimica Acta
- 點閱數
- 2626
摘要
The lead isotope composition of ocean water is not well constrained due to contamination by anthropogenic lead. Here the global distribution of lead isotopes in deep ocean water is presented as derived from dated (ca. 100 ka) surface layers of hydrogenetic Fe-Mn crusts. The results indicate that the radiogenic lead in North Atlantic deep water is probably supplied from the continents by river particulates, and that lead in Pacific deep water is similar to that characteristic of island and continental volcanic arcs. Despite a short residence time in deep water (80–100 a), the isotopes of lead appear to be exceedingly well mixed in the Pacific basin. There is no evidence for the import of North Atlantic deep water-derived lead into the Pacific ocean, nor into the North Indian Ocean. This implies that the short residence time of lead in deep water prohibits advection over such long distances. Consequently, any climate-induced changes in deep-water flow are not expected to result in major changes in the seawater Pb-isotope record of the Pacific Ocean.