East Pacific Rise: The Magnetic Pattern and the Fracture Zones

Abstract
Long-lived cosmogenic radionuclides were measured in the stone phase and in a mechanically separated metallic nodule from a fragment of the Bondoc mesosiderite. Activity levels of the various radionuclides in both phases, along with results of mass-spectrometric measurements of rare-gas isotopes in the stone phase, indicate that heavy shielding was the chief cause of the low specific activities observed.