Annotated record of the detailed examination of Mn deposits in the Atlantic Ocean from cruises from R/V Atlantis II, R/V Knorr, R/V Melvin and R/V James M. Gilliss in 1980-1981

This report is Volume 3 of Descriptions of WHOI rock dredge samples. This series represents a major effort to catalog the rock dredge samples in the WHOI Sea Floor samples collection, and to disseminate this information throughout the scientific community. Volume 3 contains sample descriptions and station data for the dredge stations from five cruises during the period September 1978 through December 1980. The material in this and subsequent volumes of rock descriptions was largely prepared onboard ship by the participating scientists. Volume 3 was printed prior to volumes 1 and 2 because of the excellent documentation of the samples represented in this volume.

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

The cores and dredges described in this report were taken on the RISEPAC Expedition from October 1961 until February 1962 by the Scripps Institution of Oceanography from the R/V Spencer F. Baird. A total of 164 cores and dredges were recovered and are available at Scripps for sampling and study.

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

The cores described in this report were taken on the BENTHIFACE Expedition in June 1973 to July 1973 by the Scripps Institution of Oceanography from the R/V Melville. A total of 128 cores and dredges were recovered and are available at Scripps for sampling and study.

(Table 2, page 2172) Chemical analytical data on thirty-two manganese nodules and crusts

Mn, Fe, Ca, Co, Ni, Cu, Zn, Cd, Sn, Tl, Pb and Bi have been estimated in thirty-two nodules from the Pacific, Atlantic and Indian oceans. Various features about the composition of manganese nodules are discussed: element abundances, degrees of enrichment, inter-element relationships (notably between Ni and Cu, and between Zn and Cd), regional variations and some aspects of statistical distribution.

Observation of manganese nodules and crusts recovered during the CHAIN 115 cruise from Nov 1973 until June 1974 in the Atlantic Ocean

Investigations of piston cores from the Vema Channel and lower flanks of the Rio Grande Rise suggest the presence of episodic flow of deep and bottom water during the Late Pleistocene. Cores from below the present-day foraminiferal lysocline (at ~4000 m) contain an incomplete depositional record consisting of Mn nodules and encrustations, hemipelagic clay, displaced high-latitude diatoms, and poorly preserved heterogeneous microfossil assemblages. Cores from the depth range between 2900 m and 4000 m contain an essentially complete Late Pleistocene record, and consist of well-defined carbonate dissolution cycles with periodicities of ~100,000 years. Low carbonate content and increased dissolution correspond to glacial episodes, as interpreted by oxygen isotopic analysis of bulk foraminiferal assemblages. The absence of diagnostic high-latitude indicators (Antarctic diatoms) within the dissolution cyclss, however, suggests that AABW may not have extended to significantly shallower elevations on the lower flanks of the Rio Grande Rise during the Late Pleistocene. Therefore episodic AABW flow may not necessarily be the mechanism responsible for producing these cyclic events. This interpretation is also supported by the presence of an apparently complete Brunhes depositional record in the same cores, suggesting current velocities insufficient for significant erosion. Fluctuations in the properties and flow characteristics of another water mass, such as NADW, may be involved. The geologic evidence in core-top samples near the present-day AABW/NADW transition zone is consistent with either of two possible interpretations of the upper limit of AABW on the east flank of the channel. The foraminiferal lysocline, at ~4000 m, is near the top of the benthic thermocline and nepheloid layer, and may therefore correspond to the upper limit of relatively corrosive AABW. On the other hand, the carbonate compensation depth (CDD) at ~4250 m, which corresponds to the maximum gradient in the benthic thermocline, is characterized by rapid deposition of relatively fine-grained sediment. Such a zone of convergence and preferential sediment accumulation would be expected near the level of no motion in the AABW/NADW transition zone as a consequence of Ekman-layer veering of the mean velocity vector in the bottom boundary layer. It is possible that both of these interpretations are in part correct. The "level of no motion'' may in fact correspond to the CCD, while at the same time relatively corrosive water of Antarctic origin may mix with overlying NADW and therefore elevate the foraminifera] lysocline to depths above the level of no motion. Closely spaced observations of the hydrography and flow characteristics within the benthic thermocline will be required in order to use sediment parameters as more precise indicators of paleo-circulation.

(Plate 3) Manganese nodules and deep-sea sediment core from Pacific Ocean

A synoptic review of the studies of well-known occurrences of palagonite tuffs is presented. Included are palagonite tuffs from Iceland, and pillow-lava palagonite complexes from Columbia River basalts and from the central Oregon coast. Additional petrologic and x-ray defraction data for selected samples are presented. Petrologic evidence shows that basaltic glass of aqueous tuffs and breccias consists of sideromelane, which is susceptible to palagonitization. It is shown that palagonitization is a selective alteration process, involving hydration, oxidation and zeolitization. Some of the manganese nodules dredged from the Pacific Ocean floor contain nucleus of palagonite-tuff breccias or of zeolite. A brief megascopic and microscopic description of nodules from the south Pacific, the Mendocino ridge and the 'Horizon' Nodule from the north Pacific is presented. Petrographic studies of palagonite-tuff breccias of manganese nodules and other palagonites suggest that migration and segregation of metallic elements occur during and subsequent to palagonitization. During the palagonitization of sideromelane, nearly 30 percent of sea water is absorbed. The hydration of sideromelane is also accompanied by oxidation of iron and other elements. These oxides may be released either in colloidal form or in true solution and tend to precipitate first from the unstable palagonite.

Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 172 stations

The cores described were taken by the personnel of the Lamont-Doherty Earth Observatory (LDEO) operating as guests scientists during the R/V Atlantis Cruise 172 undertaken by the Woods Hole Oceanographic Institution from April until June 1951. A total of 35 cores were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 167 stations

The cores described were taken by the personnel of the Lamont-Doherty Earth Observatory (LDEO) operating as guests scientists during the R/V Atlantis Cruise 167 undertaken by the Woods Hole Oceanographic Institution in January 1951. A total of 55 cores were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 160 stations

The cores described were taken by the personnel of the Lamont-Doherty Earth Observatory (LDEO) operating as guests scientists during the R/V Atlantis Cruise 160 undertaken by the Woods Hole Oceanographic Institution from Januray until April 1950. A total of 23 cores were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

Annotated record of the detailed examination of Mn deposits from VEMA 3 Expedition stations

The cores and dredges described in this report were taken during the VEMA 3 Expedition from January 1957 until June 1954 by the Lamont Geological Observatory, Columbia University from the R/V Vema. A total of 160 cores were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

Annotated record of the detailed examination of Mn deposits from R/V Robert Conrad Cruise 06 stations

The cores described in this report were taken during the R/V Robert Conrad Cruise 06 from May until June 1963 by the Lamont Geological Observatory, Columbia University. A total of 5 cores were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

Chemical composition of a manganese nodule from the Tiki Basin, Touamotou Archipelago, Pacific Ocean

The text studies the deep-sea red clays in the East-Central Pacific ocean (Tahiti-Touamotou Archipelago), their authigenic formation, transport and diagenetic character in particular through their composition in REE.

Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 179 stations

The cores described were taken by the personnel of the Lamont-Doherty Earth Observatory (LDEO) operating as guests scientists during the R/V Atlantis Cruise 179 undertaken by the Woods Hole Oceanographic Institution from April until May 1952. A total of 25 cores were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.