|Manganese crusts and nodules from the Hawaiïn Ridge|
Glasby, G.P.; Andrews, J.E. (1977). Manganese crusts and nodules from the Hawaiïn Ridge. Pac. Sci. 31(4): 363-379
In: Pacific Science. University of Hawaii Press: Honolulu,. ISSN 0030-8870, more
|Authors|| || Top |
- Glasby, G.P.
- Andrews, J.E.
Manganese stains, crusts, and nodules are widely distributed onthe insular slopes of the Hawaiian ridge. The thickness of the manganese crusts depends on depth of water, water circulation, and the age and lithology ofthe substrate, and varies from absent to stains off the island of Hawaii to a maximum of 5 cm in the vicinity of Midway. Scanning electron microscope studies indicate that the internal structure of the manganese crusts is relatively featureless compared with that of deep-sea manganese nodules. Reconsideration of ages of manganese deposits from the Hawaiian archipelago indicates that the rates of accretion of manganese crusts are probably in the same range as those ofdeep-sea deposits and that the crusts do not accrete at a much faster rate than deep-sea deposits as previously suggested. Iron staining is observedin the volcanic substrates and becomes more apparent with the increasing age of the substrate. There appears, however, to be no evidence that iron oxide is a ubiquitous control factor in initiating manganese crustal growth. Because of the terrain and the rocky nature of the substrate, diagenetic processeswithin the sediment column probably play no major role in controlling the composition of manganese crusts on the flanks of the island ridge.