Analysis of Manganese nodules from the Challenger Expedition

Manganese nodules from Stations 252 and 281 of the Challenger Expedition, collected in 1875, have recently been discovered in the Redpath Museum. The nodules have been found to be quite typical specimens of two areas in the Central Pacific Ocean except for dehydration and other changes that have taken place during storage. The principal resolvable manganese mineral in nodules from Station 252 proved to be 10 A manganite; there was a very thin surface coating of birnessite. Delta manganite was the only manganese mineral found in nodules from Station 281. Through electron microprobe studies, findings from chemical, optical and x-ray crystallographic work were correlated with the detailed picture of the occurrence and quantities of the different elements within the nodules. In all cases it was found that the iron and manganese had an antithetical relationship, and that nickel and copper were associated with the manganese. Special study was given to a 300-micron-square area in a nodule from Station 252 which included a segregation of 49.39% Mn, 5.31 % Ni, and 1.64% Cu. Crystallization of the manganese phases is thought to have provided a mech¨anism for formation of segregations which were further enriched through chemical scavenger action as long as ocean floor conditions permitted.

Annotated record of the detailed examination of Mn deposits from SESAM cruise stations

The cores and dredges described at this site were taken on the SESAM cruise from 30 April until 10 June 1976 by the Muséum National d'Histoire Naturelle from the R/V Marion Dufresne. A total of 55 cores, dredges and camera stations were recovered and are available at MNHN for sampling and study.

(page 43), Geochemical composition of a phosphatic manganese nodule from Blake Plateau

Mr. John Murray, to whom the specimens of bottom deposits collected by the "Blake" were sent for examination, looked over the whole and selected some typical specimens. These have been described in detail, and he has added some general notes on the specimens characteristic, 1. of the Coast between the Gulf of Maine and Cape Hatteras; 2. of thee coast between Cape Hatteras and Lat. 31? 48' N.; 3. of the coasts around the greater and lesser Antilles ; and, finally, of the Gulf of Mexico and Straits of Florida.

Description of manganese deposits collected by R/V "Jean Charcot" during its EQUAMARGE II expedition in the Equatorial Atlantic

During the Equamarge II cruise (February 4 to March 21, 1988), on board the R. V. "Jean Charcot", 12.500 kms of continuous geophysical profiling have been recorded along three sectors of the Equatorial Atlantic. Two segments ofthe West African transform margin have been intensively surveyed off Guinea and off Ivory Coast and Ghana. The active Romanche fracture zone has been surveyed in details on a distance of about 100 kms. These data (multibeam bathymetry, continuous seismic profiling, magnetism and gravity) have been supplemented by 16 geological stations (dredging and coring). This report gives a synthetic review of the onboard analysis and allows to better understand the geological structures of the three surveyed areas.

Annotated record of the detailed examination of Mn deposits from seventh cruise of the Carnegie (1928-1929)

The Carnegie, on its seventh cruise and last cruise, collected seventy-five samples of deep-sea deposits in the southeastern and the north Pacific. This report contains an account of the general character of the deep-sea samples collected and of the distribution of the various deposit types, together with the results of chemical, mechanical, X-ray, and other types of analyses. As indicated in the text, many of the analyses were carried out in whole or in part by other investigators.

Annotated record of the Fe-Mn concretions recovered in the Kara sea during the M. Gorkiy survey in 1945

The Kara scientific expedition of 1945, using the fishing trawler M. Gorkiy and survey vessel Osetr, took sediment samples in the Kara Sea in addition to other oceanographic work. The investigations of sediments composition was compared with biological and hydrological data obtained in the same areas. The sediments sampled were subjected to mechanical, mineralogical, chemical and faunistic analyses. During this survey iron-manganese concretions were recovered.

Chemical composition of a manganese nodule from the Pacific Ocean

By means of spectrographic analysis 96 samples of marine sediments were analyzed quantitatively for V, Ti, Zr, Co, Ni, Sc, Cr, and La, and semi-quantitatively for Ba and Sr. Ca has been estimated by visual comparison of spectrographic plates, and several Fe values have also been determined in the same way. Geographically 40 of these samples are from the Pacific Ocean basin, one of which is a manganese nodule, 21 from the Gulf of Mexico, 11 from Atchafalaya Bay, 8 from American Devonian to Miocene sedimentary rocks, 4 from the Mississippi Delta, 3 from the San Diego trough, 3 from off Grand Isle, 3 from Lake Pontchartrain, from Bay Rambour, 1 from Laguna Madre off the Texas coast, and 1 from the Guadalupe River, Texas. The afore-mentioned elements were sought using PdCl2 as an internal standard, after the method developed by Ahrens (1950) and his co-workers. Samples were run in duplicate, and standard deviations varied from 5 to 14 percent. Working curves, from which final values were obtained, were constructed with the use of standard granite, G1, and the standard diabase, W1, as standards. See Fairbairn and others (1951). An experiment was carried out to determine the effect of matrix change, involving CaCO3, on the spectral line intensities of the quantitatively analyzed elements. The distribution of each of the elements is discussed separately, and particular emphasis is given to oceanic "red clay", in which many elements are enriched. A general discussion is given to mineralogy of the sediments, cation exchange in its bearing on this thesis, and a brief recount of the two hypotheses of origin of oceanic "red clay". An application of the findings of this thesis to aid in the choice of the more likely hypothesis is made.

Observation of manganese deposits in the Blake Plateau during Atlantis Cruise 266

Since 1954 the Blake Plateau has interested the geophysical group at Woods HOle. Early cruises gathered data on this region incidental to other work. It became apparent that the area was worthy of more intense study. Questions about the bathymetry and underlying structure had been raised. This is a report of the most recent cruise undertaken to study the northern portion of the Plateau. It is intended to summarize the data collected and to be useful as art aid to investigators in preparation of manuscripts for publication.

Annotated record of the detailed examination of Mn and phosphate deposits from GOS74 Expedition stations

The purpose of the cruise was to map the manganese rich pavements of the Blake Plateau area which had been extensively investigated by ships of the Woods Hole Oceanographic Institution since 1956. From August until September 1965, 112 sites were sampled from R/V Gosnold on a joint USGS-WHOI expedition. At most of the stations on the Blake pavement, large slabs of manganese were recovered along with phosphate rich nodules.