Annotated record of the detailed examination of Mn deposits from COCOTOW Expedition stations

The cores and dredges described in this report were taken on the COCOTOW Expedition in September until December 1974 by the Scripps Institution of Oceanography from the R/V Spencer F. Baird. A total of 75 cores and dredges were recovered and are available at Scripps for sampling and study.

Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 157 stations

The cores described are taken during the R/V Atlantis Cruise 157 from August until September 1949 by the Woods Hole Oceanographic Institution. A total of 19 cores were recovered and are available at Woods Hole Oceanographic Institution for sampling and study.

Annotated record of the detailed examination of Mn deposits from the R/V Thomas Washington ROUNDABOUT Cruise stations

The cores described are taken during the R/V Thomas Washington ROUNDABOUT Cruise from May 1988 until March 1989 by the Scripps Institute of Oceanography. A total of 159 cores and dredges were recovered and are available at Scripps Institute of Oceanography for sampling and study.

Annotated record of the detailed examination of Mn deposits from SOUTHTOW Expedition stations (R/V Thomas Washington)

The cores described in this report were taken on the SOUTHTOW Expedition in June 1972 to January 1973 by the Scripps Institution of Oceanography from the R/V Thomas Washington. A total of 105 cores and dredges were recovered and are available at Scripps for sampling and study.

Annotated record of the detailed examination of Mn deposits from the TRIPOD Expedition stations

The cores and dredges described in this report were taken on the TRIPOD Expedition from November until December 1966 by the Scripps Institution of Oceanography from the R/V Argo. A total of 38 cores and dredges were recovered and are available at Scripps for sampling and study.

Annotated record of the detailed examination of Mn deposits from R/V Caryn Cruise 10 stations

The cores described are taken during the R/V Caryn Cruise 10 in July 1949 by the Woods Hole Oceanographic Institution. A total of 14 cores were recovered and are available at Woods Hole Oceanographic Institution for sampling and study.

Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 158 stations

The cores described are taken during the R/V Atlantis Cruise 158 from September until October 1949 by the Woods Hole Oceanographic Institution. A total of 5 cores were recovered and are available at Woods Hole Oceanographic Institution for sampling and study.

Annotated record of the detailed examination of Mn deposits from USS San Pablo Cruise 3 stations

The cores described are taken during the USS San Pablo Cruise 3 from July to August 1949 by the Scripps Institute of Oceanography. A total of 49 cores were recovered and are available at Scripps Institute of Oceanography for sampling and study.

Annotated record of the detailed examination of Mn deposits from R/V Velero IV Cruise 404 stations

The geographical, physical and biological aspects of the submarine canyons of the continental shelf off the coast of southern California have been described in earlier parts of this volume. Isopods were collected in 10 of the 15 canyons. Many benthic species were obtained since the specimens were obtained with a Campbell grab bottom sampler operated from the Hancock Foundation research vessel Velero IV.

Annotated record of the detailed examination of Mn nodules recovered from the VA04 expedition (R/V Valdivia) in the Pacific Ocean

Twenty-four manganese nodules from the surface of the sea floor and fifteen buried nodules were studied. With three exceptions, the nodules were collected from the area covered by Valdivia Cruise VA 04 some 1200 nautical miles southeast of Hawaii. Age determinations were made using the ionium method. In order to get a true reproduction of the activity distribution in the nodules, they were cut in half and placed for one month on nuclear emulsion plates to determine the alpha-activity of the ionium and its daughter products. Special methods of counting the alpha-tracks resolution to depth intervals of 0.125 mm. For the first time it was possible to resolve zones of rapid growth (impulse growth) with growth rates, s > 50 mm/106 yr and interruptions in growth. With few exceptions the average rate of growth of all nodules was surprisingly uniform at 4-9 mm/10 yr. No growth could be recognized radioactively in the buried nodules. One exceptional nodule has had recent impulse growth and, in the material formed, the ionium is not yet in equilibrium with its daughter products. Individual layers in one nodule from the Indian Ocean could be dated and an average time interval of t = 2600±400 yr was necessary to form one layer. The alternation between iron and manganese-rich parts of the nodules was made visible by colour differences resulting from special treatment of cut surfaces with HCl vapour. The zones of slow growth of one nodule are relatively enriched in iron. Earlier attempts to find paleomagnetic reversals in manganese nodules have been continued. Despite considerable improvement in areal resolution, reversals were not detected in the nodules studied. Comparisons of the surface structure, microstructure in section and the radiometric dating show that there are erosion surfaces and growth surfaces on the outer surfaces of the manganese nodules. The formation of cracks in the nodules was studied in particular. The model of age-dependent nodule shrinkage and cracking surprisingly indicates that the nodules break after exceeding a certain age and/or size. Consequently, the breaking apart of manganese nodules is a continuous process not of catastrophic or discontinuous origin. The microstructure of the nodules exhibits differences in the mechanism of accretion and accretion rate of material, shortly referred to as accretion form. Thus non-directional growth inside the nodules as well as a directional growth may be observed. Those nodules with large accretion forms have grown faster than smaller ones. Consequently, parallel layers indicate slow growth. The upper surfaces of the nodules, protruding into the bottom water appear to be more prone to growth disturbances than the lower surfaces, immersed in the sediment. Features of some nodules show, that as they develop, they neither turned nor rolled. Yet unknown is the mechanism that keeps the nodules at the surface during continuous sedimentation. All in all, the nodules remain the objects of their own distinctive problems. The hope of using them as a kind of history book still seems to be very remote.

Annotated record of the detailed examination of Mn deposits recovered by the Geological Survey of Japan (GSJ) during the 1971-1974 period in the Pacific Ocean

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.

Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 260 stations

The cores described here were taken during the R/V Atlantis Cruise 260 from October until November 1960 by the Woods Hole Oceanographic Institution at the Muir Seamount. A total of 27 cores and dredges were recovered and are available at Woods Hole Oceanographic Institution for sampling and study.

Annotated record of the detailed examination of Mn deposits from the Snellius II - Cruise 4 stations in the vicinity of the island of Misool, Eastern Indonesia

The chemical analyses of ferromanganese encrustations found on the seabed west of Misool, eastern Indonesia, indicate that these deposits formed in a way different from that of world-wide occurring manganese nodules. Ferromanganese coated pebbles and fragments that were found in the deeper parts of the study area probably originate from nearby ridges. The ferromanganese crust on the upper part of a dolomite fragment of ?30 kg is likely to be formed by hydrogenous processes, whereas that from the lower part seems to be formed by diagenetic processes mainly. These assumptions are supported by pore-water data from two box cores taken in the same area. The manganese and iron profiles versus depth in these cores indicate a high flux of these metals to the uppermost sediment layer, and possibly into the overlying bottom water. Factor analysis for the principal components of the microprobe analytical results of the mainly hydrogenous ferromanganese crust demonstrates a strong correlation of manganese with the trace metals, of iron with phosphorus and an antipathetic relationship between iron and manganese. Similar results have also been reported for abyssal manganese nodules in the world oceans. Factor analysis for the principal components of the analytical data obtained for the diagenetic ferromanganese crust results in a clear dolomite (Ca/Mg) dilution factor only.

Annotated record of the detailed examination of Mn deposits from SEVENTOW (7TOW) Expedition stations

The cores described in this report were taken on the SEVENTOW Expedition in February-September 1970 by the Scripps Institution of Oceanography from the R/V Thomas Washington. A total of 193 cores and dredges were recovered and are available at Scripps for sampling and study.

Annotated record of the detailed examination of Mn deposits from the QUEBRADA (1969) and SIQUEIROS (1974) expeditions around the East Pacific Rise

Basalt samples obtained from the Siqueiros transform fault/fracture zone and the adjacent East Pacific Rise are mostly very fresh oceanic tholeiite and fractionated oceanic tholeiite with Fe+3/ Fe+2 ? 0.25; however, alkali basalts occur in the area as well. The rocks of the tholeiitic suite are ol + pl phyric and ol + pl + cpx phyric basalts, while the alkali basalts are ol and ol + pl phyric. Microprobe analyses of the tholeiitic suite phenocrysts indicate that they are Fo68-Fo86, An58-An75, and augite (Ca34Mg50Fe16). The range of olivine and plagioclase compositions represents the chemical variation of the phenocryst compositions with fractionation. The phenocyrsts in the alkali basalts are Fo81 and An69. The suite of tholeiites comprises a fractionation series characterized by relative enrichment of Fe, Ti, Mn, V, Na, K, and P and depletion of Ca, Al, Mg, Ni, and Cr. The fractionated tholeiites occur on the median ridge (which is a sliver of normal oceanic crust) of the double Siqueiros transform fault, on the western Siqueiros fracture zone, and on the adjoining East Pacific Rise, while the two transform fault troughs contain mostly unfractionated or only slightly fractionated tholeiite. We suggest that the fractionated tholeiites are produced by fractional crystallization of more 'primitive' tholeiitic liquid in a crustal magma chamber below the crest of the East Pacific Rise. This magma chamber may be disrupted by the transform fault troughs, thus explaining the paucity of fractionated tholeiites in the troughs. The alkali basalts are found only on the flanks of a topographic high near the intersection of the northern transform trough with the East Pacific Rise.