Publication Date:
2023-08-28
Description:
In 1974, the Geological Survey of Japan began its systematic investigation of manganese nodules in the Central Pacific Basin on the new geological research vessel Hakurei Maru. The first cruise (GH 74-5) was carried out over an eastern part area of the Basin (6°-10°30'N, 164°30'-171°30'W), and the authors report here the preliminary results on the occurrence of manganese nodule deposits, paying particular consideration to their relationship to submarine topography and surficial and sub-bottom sedimentary facies. The surveyed area comprises a deep-sea basin at 5,000-5,400 m, defined to the north and east by the chain of seamounts and guyots of the Christmas Ridge. The deep-sea basin is divided roughly into 2 contrasting topographic features. The eastern part is characterised by flattened topography resulting from continuous deposition of turbidities; the meridian and western parts are characterised by gently rolling topography and the existence of a large number of deep-sea hills. Manganese nodules are almost lacking in the former flattened eastern area, whereas they are widely distributed in the latter rolling meridian and western parts. The population density of nodules varies from less than 1 Kg/m² to 26 kg/m² and the higher density is found in the siliceous-calcareous ooze zone of rather small, flat basins surrounded by deep-sea hills. The density is closely related to the thickness of the transparent layer obtained by 3.5 kHz PDR profiling over the whole area. Considering the various data of grab sampling, 3.5 kHz PDR profiling and to a lesser extent of deep-sea television and camera observations, the most promising manganese field in the present area seems to be confined to the north of the western sector of the area.
Keywords:
Comment; Deposit type; DEPTH, sediment/rock; Dredge; DRG; Elevation of event; Event label; GH74-7; GH74-7-150-1; GH74-7-150-2; GH74-7-155; GH74-7-159; GH74-7-160; GH74-7-175; GH74-7-177; GH74-7-179; GH74-7-180; GH74-7-182; GH74-7-183; GH74-7-184; GSJ-71106; GSJ-71107; GSJ-71111; GSJ-71203; GSJ-71208; GSJ-73101; GSJ-73104; GSJ-73109; GSJ-73113; GSJ-73116; Hakurei-Maru (1974); Latitude of event; Longitude of event; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Pacific Ocean; Position; Sample ID; Sediment type; Size; Substrate type
Type:
Dataset
Format:
text/tab-separated-values, 102 data points
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