A geochemical study of metalliferous sediment from the TAG Hydrothermal Mound, 26°08′N, Mid-Atlantic Ridge
Article first published online: 20 SEP 2012
Copyright 1993 by the American Geophysical Union.
Journal of Geophysical Research: Solid Earth (1978–2012)
Volume 98, Issue B6, pages 9683–9692, 10 June 1993
How to Cite
1993), A geochemical study of metalliferous sediment from the TAG Hydrothermal Mound, 26°08′N, Mid-Atlantic Ridge, J. Geophys. Res., 98(B6), 9683–9692, doi:10.1029/92JB01705., , , , , , , and (
- Issue published online: 20 SEP 2012
- Article first published online: 20 SEP 2012
- Manuscript Accepted: 15 JUL 1992
- Manuscript Received: 17 JUN 1991
An Alvin push core collected near the base of the TAG hydrothermal mound, 26°08′N, Mid-Atlantic Ridge, sampled a 7 cm-thick layer of Fe-rich red-brown mud (20–40% Fe) overlying a 4 cm-thick layer of carbonate ooze (5–70% CaCO3) which also contains up to 32%Fe. On the basis of chemical compositions, two separate layers can be identified within the red-brown mud. The core position, X ray diffractometry, Pb isotope analyses, and elemental abundances all indicate that these two layers were derived from mass wasting of oxidized, originally sulphidic material from the slopes of the TAG hydrothermal mound. High concentrations (11–19 ppm) of seawater-derived U occur in both Fe-rich layers. These enrichments may derive from uptake of U linked to the oxidation of sulphide phases. Metal concentrations in the rich layer are lower than in the upper part of the core but higher than in open ocean pelagic sediments. The 230Thxs/Fe, 231Paxs/Fe, and rare earth element/Fe distributions indicate that the hydrothermal input to the carbonate-rich layer is dominated by settling of suspended particulate material from the overlying hydrothermal plume. Such CaCO3-rich sediments may record an important component of the flux of hydrothermal material to sediments of the Mid-Atlantic Ridge rift valley.