MANOP Site H manganese nodules and crusts chemical composition determined by instrumental neutron activation (INAA)

Manganese nodules and crusts were sampled from box cores collected at the Manganese Nodule Program (MANOP) site H in the Eastern Equatorial Pacific ocean. For majority of site H nodule bottoms have smooth, lustrous patches, whereas nodule tops are generally rough and dull. The top/bottom orientation of each manganese nodule was labeled during curation. Most of the nodutes studied were cut in haIf, and a 3-5 mm layer was scraped from nodule tops and bottoms. The chemical analysis was performed on both top and bottom sides as well as on the whole specimen. They were analysed at the U.S. Geological Survey, Menlo Park using instrumental neutron activation analysis with high-resolution lithium-drifted germanium detectors. This method involves the meeasurement of gamma-ray emission after proper irradiation of the samples.