skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Manganese, methane, iron, zinc, and nickel anomalies in hydrothermal plumes from Teahitia and Macdonald volcanoes

Journal Article · · Geochimica et Cosmochimica Acta; (United States)
; ;  [1];  [2];  [3]; ; ;  [4]
  1. Univ. Kiel (Germany)
  2. Inst. de Physique du Globe de Paris (France)
  3. Univ. of Hawaii, Honolulu (United States)
  4. Univ. Hamburg (Germany)

Hydrothermal vents discharging turbid water have recently been discovered at Teahitia and Macdonald seamounts, which are situated at the southeast ends of two South Pacific hotspot systems. Mixtures of the plumes with ambient seawater were sampled during the 1989 CYAPOL cruise and found to contain significant amounts of CH[sub 4], Mn, Fe, Zn, and Ni, which are comparable in concentration to those found over hydrothermal fields on the EPR and in megaplumes over the Juan de Fuca Ridge. Above Teahitia volcano, CH[sub 4] shows maximum concentrations of 8 nmol/kg, Mn concentrations of 19 nmol/kg, and Fe concentrations of 125 nmol/kg. The concentrations were much higher during an earlier SO-47 cruise in 1987, reaching maximum values of 14 nmol CH[sub 4]/kg and 60 nmol Mn/kg. By contrast, the Macdonald seamount plume shows an opposite trend reaching very high concentrations of 350 nmol/kg CH[sub 4], 250 nmol Mn/kg, and 3,920 nmol Fe/kg during the CYAPOL cruise when the volcano was at an eruptive stage with high seismic activity. Mapping of the element concentrations in the water column shows the plume ceiling, or anomaly maxima, to occur to several hundred meters above the seafloor and up to several kilometers (>5 km) from the vents on Macdonald seamount. Multiple maxima in hydrocast profiles indicate the presence of several distinct hydrothermal vents at different water depths on Teahitia and on the western flank of Macdonald seamount. REE data from a single hydrocast over the active Macdonald summit indicate a mobility of the REE, which probably results from high-temperature basalt-seawater interaction.

OSTI ID:
6962764
Journal Information:
Geochimica et Cosmochimica Acta; (United States), Vol. 56:10; ISSN 0016-7037
Country of Publication:
United States
Language:
English