Concentrations of Fe, Mn, Cu, Zn, Co, Ni, Pb, Cd, B, and SiO2 in interstitial waters from bottom sediments of the Atlantis II and Discovery Deeps, Red Sea rift zone

Chemical analyzes show that interstitial waters from ore-bearing bottom sediments of the Atlantis II and Discovery Deeps are enriched in Fe, Mn, Cu, Ni, Co, Zn, Pb, and Cd compared to sea water. Enrichment factors of these trace elements in the interstitial waters of the Atlantis II Deep relative to the sea water vary within the following ranges: for Fe from 100 to 7000, for Mn from 19047 to 32738, for Zn from 500 to 1600, for Pb from 78333 to 190000, for Cu from 107 to 654. Comparison of average weighted concentrations of Fe, Mn, Zn, Pb, Cu, Ni in the bottom sediments and the interstitial waters of the Atlantis II Deep indicates common regularities and good relationship in distribution of these elements along sediment cores. Differences in concentrations and distribution of the studied trace elements in the interstitial waters of the Atlantis II and Discovery Deeps result from different chemical compositions of hydrothermal fluids entering these deeps.

Concentration of hydrogen in hot brines of the Atlantis II Deep

An analysis of earlier measurements and author's data serves as a basis for a discussion of origin of deep-sea hydrogen. High hydrogen concentrations (0.001 ml/l or higher) in geothermal brines of the Atlantis II Deep depression are of abiogenic origin.

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 SAFARI II cruise stations

The cores and dredges described at this site were taken on the SAFARI II cruise from 21 July until 1 September 1981 by the MusÈum National d'Histoire Naturelle from the R/V Marion Dufresne. A total of 65 cores, dredges and camera stations were recovered and are available at MNHN for sampling and study.