Ito, T.; Komuro, K.; Hatsuya, K.; Nishi, Hiroshi (2006): Chemical compositions of ferromanganese micronodules in sediments at Site 1216, ODP Leg 199, Paleogene equatorial transect. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Wilson, Paul A., Lyle, Mitchell W., Janecek, Thomas R., Backman, Jan, Busch, William H., Coxall, Helen K., Faul, Kristina, Gaillot, Philippe, Hovan, Steven A., Knoop, Peter, Kruse, Silke, Lanci, Luca, Lear, Caroline, Moore, Theodore C., Nigrini, Catherine A., Nishi, Hiroshi, Nomura, Ritsuo, Norris, Richard D., Palike, Heiko, Pares, Josep M., Quintin, Lacie, Raffi, Isabella, Rea, Brice R., Steiger, Torsten H., Tripati, Aradhna, Vanden Berg, Michael D., Wade, Bridget, Proceedings of the Ocean Drilling Program; scientific results; Paleogene equatorial transect; covering Leg 199 of the cruises of the drilling vessel JOIDES Resolution; Honolulu, Hawaii, to Honolulu, Hawaii; Sites 1215-1222; 23 October-16 December 2001, 199, georefid:2007-028670

Abstract:
Distribution, size, mineral, and chemical compositions of ferromanganese micronodules (FMMNs) and chemical composition of host sediments were examined in a series of red clay samples with ages from Eocene to the present at Ocean Drilling Program Leg 199, Site 1216, south of the Molokai Fracture Zone in the Central Pacific Basin. The number of FMMNs changed drastically throughout the 40-m long red clay intervals. FMMNs are abundant in the upper 9 m of core, decrease between 9 and 25 meters below seafloor (mbsf) with depth, and are very rare from 30 to 40 mbsf. Chemical composition of FMMNs showed high Mn/Fe ratios and Ni and Cu contents and a distinct positive Ce anomaly because of the existence of buserite. This suggests that FMMNs in the red clay from 25 mbsf to the top of the cored interval were deposited continuously in an oxic diagenetic bottom environment. The red clay below 30 mbsf with higher Mn contents contains few FMMNs but abundant tiny Mn particles within brown silicates coated by Fe (oxy-hydro)oxides. This indicates that the mode of manganese deposition changed between 25 and 30 mbsf.
Coverage:
West: -139.2900 East: -139.2900 North: 21.2700 South: 21.2700
Relations:
Expedition: 199
Site: 199-1216
Supplemental Information:
Available only on CD-ROM in PDF format and on the Web in PDF or HTML
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.199.211.2006 (c.f. for more detailed metadata)
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