Geological and geochemical data for seamounts and associated ferromanganese crusts in and near the Hawaiian, Johnston Island, and Palmyra Island Exclusive Economic Zone

Hein, James R.; Manheim, Frank T.; Schwab, William C.; Davis, Alicé S.; Daniel, Cuevas; Bouse, Robin M.; Morgenson, L.A.; Sliney, Rosemary E.; Clague, David A.; Tate, George; Cacchione, David A.

doi:10.3133/ofr85292

Cited by 18 publications

(4 citation statements)

References 5 publications

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“…It has been well established that Co content in general decreases from outer crust layers to inner crust layers (Halbich et al, 1982;Hein et al, 1985b). This relation can also be demonstrated here (Table 15) where Co increases with decreasing crust thickness anc Co is greater in outer layers relative to inner layers of the crusts (Table 13).…”

Section: Layerssupporting

confidence: 82%

Geological, geochemical, geophysical, and oceanographic data and interpretations of seamounts and co-rich ferromanganese crusts from the Marshall Islands, KORDI-USGS R.V. Farnella cruise F10-89-CP

Hein¹,

Kang²,

Schulz³

et al. 1990

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characteristic of mid-plate Cretaceous seamounts. The channels act as conduits for sediment and talus debris. The bathymetry shown for the other seamounts (Figs. 7-12) is modified from Chase and Menard (1973) by changing the water depths from fathoms to meters (Chase, Seekins, and Young, U.S. Geological Survey, unpublished data, 1988). Airgun and 3.5 kHz Lines This section provides a brief description of each of the 37 seismic lines collected on F10-89-CP (Table 3; Figs. 13-' 9). The 156 km long Line 1 crosses Ruwituntun and Look Seamounts from the southeast to the northwest (Figs. 13-17). The shallowest water depth over the summit of Ruwituntun Seamount is 1215 m. Hie rugged summit platform of Ruwituntun Seamount consists of a series to basement knolls and basins filled or partly filled with sediment. Craters can be distinguished on the volcanic pinnacles to the southeast. Sediment thickness varies from 104 m in the summit-edge basins to 32 m for interior basins. The sediment drape is thicker on the southeast sides of volcanic pinnacles. The summit platform may tilt slightly to the southeast. 1 he upper to lower flank slope angles increase from 11° to 28° for the southeast flank and from 13° to 17° for the northwest flank. The pass between the two seamounts is rugged, showing volcanic pinnacles, sediment fill, slump deposits, and talus. The summit of Look Seamount shallows to 1000 m water depth aid consists of mostly small volcanic pinnacles draped by a thin layer of sediment. Sediment thickness varies from 0 m to 40 m on the summit and slumps and talus occur on the lower slopes. Slope angles range between 1 \ and 14°, although the lower northwest slope is 33°. The 33 km long Line 2 crosses the lower north-northwest flank of Look Seamount (Figs. 18, 19). The line shows mostly talus debris and slump structures, with abyssal sediment covering the lowermost slope at the northeast end of the line. Hie 46 km long Line 3 crosses Look Seamount from north to south (Figs. 20, 21). The summit shaUows to 999 m water depth, consistent with the line 1 crossing. The summit topography is irregular with small sediment-filled basins. Maximum sediment thickness is 32 m. The sedimentary section is nearly transparent witp few internal reflectors. Pelagic sediment at least several hundred meters thick laps up on the lower south flank. The water depth to abyssal sediment is about 400 m deeper on the north flank than on the south flank. Lines 4 through 9 total 241 km and cross North and South Laanmqjanjan Seamounts (Figs. 22-32), which are elongated in a northsouth direction. Hie summit of South Laanmqjanjan is about 7 km westnorthwest of its position on the Chase and Menard (1973) base map. Little or no sediment occurs on the summit or upper flanks of these generally very rugged seamounts (see Line 6; Figs. 26, 27). The shallowest water depth, 1090 m, was recorded at the end of line 9 (Pigs. 31, 32), which ended at the summit of North Laanmojanjan. Upper and lower slope angles vary from 9 to 17° and from 9 to 25°, respectively. The w...

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Section: Layerssupporting

confidence: 82%

Geological, geochemical, geophysical, and oceanographic data and interpretations of seamounts and co-rich ferromanganese crusts from the Marshall Islands, KORDI-USGS R.V. Farnella cruise F10-89-CP

Hein¹,

Kang²,

Schulz³

et al. 1990

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“…The associations of Co, Ni, V, and Mo with Mn are generally stronger in the dredged subset matrix, reflect the influence of depth-dependent hydrogenetic enrichment processes (Halbach and Puteanus, 1984), and are consistent with other studies (Aplin and Cronan, 1985a;Halbach et al, 1982;Hein et al, 1985bHein et al, , 1988De Carlo et al, 1987a, 1987b. Figure 3 also shows that Co and Ni are strongly associated with each other, with slightly more scatter observed in the dredged data set.…”

Section: Interelement Correlationssupporting

confidence: 90%

“…More recently a renewed interest in marine minerals has led to the exploration of seamount Fe-Mn crust deposits because these are enriched in the currently more valuable metal Co relative to their abyssal nodule counterparts. Work discussing seamount Fe-Mn crusts includes, but is not limited to, Craig et al (1982), Halbach et al (1982Halbach et al ( , 1983, Halbach and Manheim (1984), Aplin andCronan (1985a, 1985b), Hein et al (1985aHein et al ( , 1985bHein et al ( , 1988, De Carlo et al (1987aCarlo et al ( , 1987b, Pichoki and Hoffert (1987), and De Carlo and Fraley (1990). Summaries of nodule and crust data from the Australian region have been presented by Jones (1980) and Exon et al (in press).…”

Section: Introductionmentioning

confidence: 99%

Ferromanganese Deposits from the Wombat Plateau, Northwest Australia

Carlo¹,

Exon²

1992

Proceedings of the Ocean Drilling Program

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Ferromanganese crusts, nodules, and ferromanganese-rich sediments were recovered on the Wombat Plateau, northwest Australian continental margin, by dredging during Bureau of Mineral Resources cruise 56 of Rig Seismic and by drilling during ODP Leg 122 of JOWES Resolution. We report here the chemistry and mineralogy of the ferromanganese crusts, nodules, and associated ferromanganese-rich sediments. The ferromanganese deposits from the ODP sites are up to 40 cm thick and probably formed in Late Cretaceous to Eocene times. Those from outcrops usually formed in several phases, and their age is unconstrained except that the substrates are Mesozoic. The samples were recovered from present-day water depths of 2000-4600 m, on the Wombat Plateau adjacent to the Argo Abyssal Plain. Both the nodules and crusts are primarily vernadite (δ-MnO 2) and are chemically and mineralogically similar, and not dissimilar from ferromanganese deposits found elsewhere on Australian and other marginal plateaus. They are markedly different from most deep-sea deposits. The only crystalline iron phase identified within the ferromanganese deposits is goethite. Concentrations of metals of potential economic interest are generally low compared to those from vernadite-rich seamount crusts and nodules and from abyssal nodules from areas of high resource potential in the Pacific Ocean. Maximum metal values reach 0.55% Co, 0.58% Ni, and 0.20% Cu in deposits containing 4.8% to 30.9% Fe and 4.4% to 21.1% Mn.

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“…Layers: In general, Co contents decrease from the outer surface to the substrate through Fe-Mn crusts (Halbach et al, 1982;Hein et al, 1985b); but in Tunes 6 samples, only about half show that decrease (Tables 6,7), whereas in the other half Co increases with depth; in one sample, the Co content remains unchanged with depth in the crust. This geographic area is unique in having so many samples that show an increase in Co with depth in the crusts.…”

Section: Chemistrymentioning

confidence: 99%

Composition of Co-rich ferromanganese crusts and substrate rocks from the NW Marshall Islands and international waters to the north, Tunes 6 cruise

Hein¹,

Zielinski²,

Staudigel³

et al. 1997

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This report is preliminary and has not been reviewed for conformity with the U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. plasma-atomic emission spectrometry, except those of K, Zn, and Pb, which were determined by flame atomic-absorption spectroscopy, and those of As, Cr, and Cd, determined by graphite-furnace atomic absorption spectroscopy on air-dried samples (Aruscavage et al., 1989). Concentrations of platinum-group elements (PGEs) and rare earth elements (REEs) for Fe-Mn crusts were determined by inductively coupled plasmamass spectrometry (Lichte et al., 1987a,b). The usual Pearson product moment correlation coefficient was used to calculate the correlation coefficient matrices. For Q-mode factor analysis, each variable percentage was scaled to the percent of the maximum value before the values were row-normalized and cosine theta coefficients calculated. Factors were derived from orthogonal rotations of principal component eigenvectors using the Varimax method (Klovan and Imbrie, 1971). All communalities are >0.93. Low factor scores, < 10.21, were discarded because they are not statistically significant. SUBSTRATE ROCK DESCRIPTIONS AND COMPOSITION Substrate rocks in decreasing order of abundance are basalt, breccia, phosphorite, hyaloclastite, limestone, volcaniclastic siltstone and sandstone, and mudstone (Table 1). As many as five different rock types were recovered in a single dredge haul. As seen in hand samples, breccias most commonly consist of basalt clasts in a hyaloclastite matrix, and/or carbonate fluorapatite (CFA) cement. Many samples have Mn oxide impregnations that commonly form dendrites. Volcanogenic clasts in breccias and volcaniclastic rocks are commonly replaced by clay minerals and iron oxides. Basalts are aphanitic with common plagioclase phenocrysts and CFA infilling fractures and vesicles. Some samples have vesicles filled with carbonate mud or Fe-Mn oxides. Reef limestones consist of rounded carbonate clasts with calcite cement and moldic porosity; pelagic limestones are micritic and bioturbated to massive. Mudstones are mostly bioturbated with Fe-Mn oxides lining some burrows. Phosphorites have carbonate mud in cracks and Fe-Mn oxide impregnations. X-ray Diffraction Mineralogy and Petrography Primary Volcanogenic and sedimentary minerals include plagioclase, pyroxene, magnetite, and calcite; and secondary minerals include CFA, smectite, calcite, phillipsite, clinoptilolite, goethite, hematite, barite, and potassium feldspar (Table 2). Secondary CFA is the most abundant mineral in these samples and occurs in 73% of the samples as a major or moderate constituent, regardless of rock type (Table 2). Hyaloclastite and hyaloclastite breccias consist chiefly of CFA and phillipsite (Table 2), with moderate to minor amounts of plagioclase, pyroxene, and magnetite. Most samples contain minor amounts of smectite. One sam...

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Geological and geochemical data for seamounts and associated ferromanganese crusts in and near the Hawaiian, Johnston Island, and Palmyra Island Exclusive Economic Zone

Cited by 18 publications

References 5 publications

Geological, geochemical, geophysical, and oceanographic data and interpretations of seamounts and co-rich ferromanganese crusts from the Marshall Islands, KORDI-USGS R.V. Farnella cruise F10-89-CP

Geological, geochemical, geophysical, and oceanographic data and interpretations of seamounts and co-rich ferromanganese crusts from the Marshall Islands, KORDI-USGS R.V. Farnella cruise F10-89-CP

Ferromanganese Deposits from the Wombat Plateau, Northwest Australia

Composition of Co-rich ferromanganese crusts and substrate rocks from the NW Marshall Islands and international waters to the north, Tunes 6 cruise

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