important metals and minerals found on the seafloor. Although mining in the ocean has advantages over mining on land (extraction requires a smaller footprint, for example), economic and technological hurdles as well as environmental concerns have yet to be resolved. Despite these obstacles, the first section of ocean0.1 square kilometer off Papua New Guineawas set to be commercially mined in early 2018. Financing the project has proven difficult, delaying the start date to early 2019. USGS provides expertise in analyzing the metals and other elements in these mineral deposits, which occur in many deep-ocean settings from the Arctic to the Antarctic. USGS also researches environmental issues related to their recovering the mineral resources these deposits contain. Knowing their attributes and how these features form on the seafloor benefits many agencies, including the International Seabed Authority, which regulates mining in international waters and areas leased within a countrys Exclusive Economic Zone. USGS information about deep ocean minerals helps guide stakeholders to make informed decisions on environmental issues, resource use, and energy production.https://walrus.wr.usgs.gov/research/projects/pac_eez_minerals.htmlCritical metals in manganese nodules from the Cook Islands EEZ, abundances and distributions. Author links open the author workspace.James R.Heina. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceOpens the author workspaceOpens the author workspace. Author links open the author workspace.FrancescaSpinardia. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace. Author links open the author workspace.NobuyukiOkamotob. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace. Author links open the author workspace.KiraMizella. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace. Author links open the author workspace.DarrylThorburnc. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace. Author links open the author workspace.AkuilaTawaked. Numbers and letters correspond to the affiliation list. Click to expose these in author workspacea U.S. Geological Survey, PCMSC, 400 Natural Bridges Dr., Santa Cruz, CA 95060, USA bSea-Floor Mineral Resources R&D Division, Metals Mining Technology Dept., JOGMEC, 2-10-1 Toranomon, Minato-ku, Tokyo 105-0001, Japan c Seabed Minerals Authority, Avarua, Rarotonga, Cook Islands d SOPAC Division of the SPC, Private Mail Bag, GPO, Suva, Fijihttps://doi.org/10.1016/j.oregeorev.2014.12.011Highlights Cook Islands EEZ has the highest abundance of manganese nodules over the largest area. Cook Islands nodule field is a world-class metal resource for critical metals. Metals of economic importance include Mn, Ti, Co, Ni, and rare-earths plus yttrium.AbstractThe Cook Islands (CIs) Exclusive Economic Zone (EEZ) encompasses 1,977,000 km2 and includes the Penrhyn and Samoa basins abyssal plains where manganese nodules flourish due to the availability of prolific nucleus material, slow sedimentation rates, and strong bottom currents. A group of CIs nodules was analyzed for mineralogical and chemical composition, which include many critical metals not before analyzed for CIs nodules. These nodules have varying sizes and nuclei material; however all are composed predominantly of -MnO2 and X-ray amorphous iron oxyhydroxide. The mineralogy, Fe/Mn ratios, rare earth element contents, and slow growth rates (mean 1.9 mm/106 years) reflect formation primarily by hydrogenetic precipitation. The paucity of diagenetic input