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HERO ID
4270791
Reference Type
Journal Article
Title
Continuous growth of hydrogenetic ferromanganese crusts since 17 Myr ago on Takuyo-Daigo Seamount, NW Pacific, at water depths of 800-5500 m
Author(s)
Usui, A; Nishi, K; Sato, H; Nakasato, Y; Thornton, B; Kashiwabara, T; Tokumaru, A; Sakaguchi, Aya; Yamaoka, K; Kato, S; Nitahara, S; Suzuki, K; Iijima, K; Urabe, T
Year
2017
Is Peer Reviewed?
1
Journal
Ore Geology Reviews
ISSN:
0169-1368
EISSN:
1872-7360
Volume
87
Page Numbers
71-87
DOI
10.1016/j.oregeorev.2016.09.032
Web of Science Id
WOS:000405880900007
Abstract
Ferromanganese crusts cover all outcrops on Takuyo-Daigo seamount traversed during remotely operated underwater vehicle (ROV) dives, except in places covered by foraminifera sand. Takuyo-Daigo is a Cretaceous sea mount located in the northwest Pacific Ocean. Geological and bathymetric mapping provide the framework for this study. Chemical and mineralogical analyses of the hydrogenetic ferromanganese crusts show temporal and spatial variations typical of those found in previous studies. Outcrops from 800 to 5500 m water depths are covered with ferromanganese crusts up to 105 mm thick. Beryllium isotope dating shows that the crusts have apparently been growing continuously at all water depths, even through the modern oxygen minimum zone (OMZ), contrary to some earlier models for deposition. Growth rates vary from 2.3 to 3.5 mm/Myr, with Fe or Mn fluxes of 0.07-0.11 g/cm(2)/Myr since the early-middle Miocene. Co/Mn ratios decrease with water depth while Fe/Mn and other metallic elements increase or show no change, based on the analysis of the uppermost crust surface. This is probably because Co is the most abundant redox-sensitive element derived from seawater that occurs in crusts. (C) 2016 Elsevier B.V. All rights reserved.
Keywords
Ferromanganese crust; Oxygen minimum zone (OMZ); Northwest Pacific; Talcuyo-Daigo; Seamount; Hydrogenetic; Outcrop Marine minerals; International Seabed Authority/United Nations (ISA/UN); Paleoceanography; Remotely operated underwater vehicle (ROV)
Tags
IRIS
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Cobalt
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