IRON ENRICHMENTS IN HYDROTHERMAL PLUMES OVER THE EAST PACIFIC RISE

Abstract

Manganese, iron, and helium isotopes have been measured in samples taken near the crest of the East Pacific Rise at 19°S. Samples were enriched in Mn and in He isotopes, as is typical for waters of this area. Samples were also enriched in Fe; Fe enrichments covary with Mn and3He enrichments. The Fe/Mn ratio at four sites ranged from about 2 to 9, spanning the average value found for metalliferous sediments (3.5).