Formation of ferromanganese crusts on northwest intertropical Pacific seamounts: electron photomicrography and microprobe chemistry SCIE SCOPUS

Cited 21 time in WEB OF SCIENCE Cited 0 time in Scopus
Title
Formation of ferromanganese crusts on northwest intertropical Pacific seamounts: electron photomicrography and microprobe chemistry
Author(s)
Jeong, KS; Jung, HS; Kang, JK; Morgan, CL; Hein, JR
KIOST Author(s)
Jeong, Kap Sik(정갑식)Jung, Hoi Soo(정회수)
Publication Year
2000-01-15
Abstract
Seven ferromanganese crusts from the northwest intertropical Pacific seamounts were analyzed for photomicroscopic growth structures, microprobe chemistry, and ages based on Co-chronometer growth rate. The crusts on the Marshall Islands seamounts are thick and are divided into phosphatized lower older and nonphosphatized upper younger growth generations: the older crust consists of compact laminations and columns impregnated with carbonate fluoapatite (CFA), whereas the younger crust is characterized by porous botryoids and columns of delta-MnO2 and Fe oxyhydroxide. The crusts on the Federated States of Micronesia (FSM) and Palau Islands seamounts are thin and are often incorporated with inorganic opal-A in the uppermost part, comprising the younger generation. Some crusts show scours and fractures. Although the growth of crusts has been often interrupted by mass failure of slope sediments, the crusts on the Marshall Islands seamounts are estimated to have grown at rate of about 3 mm/Ma since the middle Eocene and to have been phosphatized in the late Oligocene during the host seamounts were located beneath the equatorial zone of high productivity. Prolonged infiltration of the oxygen minimum zone (OMZ) water into shallower water older crusts redistributed crust composition by precipitating CFA, enriching subsequent amounts of Mn and Ni, and removing some Co. The younger crust has formed at slower rate (about 2 mm/Ma) under the stronger influence of bottom-water circulation in the north of the equatorial zone, concentrating abundant Co. In the uppermost part of some crusts, siliceous skeletons transform with burial to inorganic opal-A and Si-rich Fe oxyhydroxide, suggesting that biosilica diagenesis can enhance crust growth. (C) 2000 Elsevier Science B.V. All rights reserved.
ISSN
0025-3227
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/6080
DOI
10.1016/S0025-3227(99)00091-2
Bibliographic Citation
MARINE GEOLOGY, v.162, no.2-4, pp.541 - 559, 2000
Publisher
ELSEVIER SCIENCE BV
Subject
CENTRAL EQUATORIAL PACIFIC; CAROLINE ISLANDS; OXIDE DEPOSITS; GROWTH-RATES; COBALT-RICH; OCEAN; MANGANESE; GEOCHEMISTRY; DISSOLUTION; EVOLUTION
Keywords
ferromanganese crusts; northwest intertropical Pacific; two growth generations; phosphatization; oxygen minimum zone; biosilica diagenesis
Type
Article
Language
English
Document Type
Article
Publisher
ELSEVIER SCIENCE BV
Related Researcher
Research Interests

Marine geology,해양지질

Files in This Item:
There are no files associated with this item.

qrcode

Items in ScienceWatch@KIOST are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse