Abstract
The physics and chemistry of the near-bottom water column above Gorda Ridge were studied for indications of hydrothermal venting. Based on initial sea-floor surveys, three field programs focused on Northern Gorda Ridge, using state-of-the-art shipboard and in situ determinations of physical, optical, and chemical properties useful in “prospecting” for active venting. The results of these investigations demonstrate the presence of active venting in at least two regions of the northernmost ridge segment—the “Narrowgate” section (GR14), and the east slope of the axial valley near its intersection with Blanco Fracture Zone (GR15). Distinct temperature anomalies (≈30 millidegree C) and suspended particle “plumes” were found at both locations during two separate expeditions in 1985. These plumes had stabilized at depths between 2450 and 2900 m and were separated from the bottom by at least 200 m. Detailed sections through the plume at GR14 demonstrated dimensions of at least 2 km (east-west) and 2 to 4 km (north-south), centered over the east wall of the axial valley. The plumes at GR14 and GR15 were not physically connected along the ridge axis. Chemical anomalies in the plumes included high concentrations of dissolved manganese, helium-3, radon-222, and iron-rich hydrothermal precipitates. The composition and hydrography of the plumes suggest that they originated from high-temperature vents. A brief reoccupation of the GR14 site in 1986 failed to relocate these strong plume features.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Baker ET, Massoth GJ, Collier RW, et al. (1987) Evidence for high-temperature hydrothermal venting on the Gorda Ridge, northeast Pacific Ocean. Deep-Sea Res 34: 1461–1476.
Clague D, Friesen W, Quinterno P, et al. (1984) Preliminary geological, geophysical, and biological data from the Gorda Ridge. USGS Open-File Report 84–364, 49 pp.
Clarke WB, Beg MA, Craig H (1969) Excess helium-3 in the sea: Evidence for terrestrial primordial helium. Earth Planetary Sci Lett 6: 213–220.
Collier RW, Holbrook SH, Robbins JM (1986) Studies of trace metals and active hydrothermal venting on the Gorda Ridge. State of Oregon, Department of Geology and Mineral Industries Open-File Report 0–86–13, 36 pp.
Cowen JP, Massoth GJ, Baker ET (1986) Bacterial scavenging of Mn and Fe in a mid- to far-field hydrothermal plume. Nature 322: 169–171.
Dymond J, Corliss JB, Heath GR, Field CW, Dasch EJ, Veeh HH (1973) Origin of metalliferous sediments from the Pacific Ocean. Geol Soc Am Bull 84:3355–3372.
Edmond JM, Measures C, McDuff RE et al. (1979) Ridge crest hydrothermal activity and the balances of the major and minor elements in the ocean: The Galapagos Data. Earth Planetary Sci Lett 46: 1–18.
Grassle JF (1986) The ecology of deep-sea hydrothermal vent commonities. Adv Marine Biol 23: 301–362.
Hickey B (1986) The California Current System-hypotheses and facts. Prog Oceanogr 8: 191–279.
Kadko D, Lupton JE, Collier R, Lilley MD, Pak H (1986) Endeavour Ridge hydrothermal plume study. EOS 67: 974 (abstract).
Lyle M, Leinen M, Owen RM, Rea DK (1987) Late tertiary history of hydrothermal deposition at the East Pacific Rise, 19°S′: Correlation to volcano-tectonic events. Geophys Res Lett 14: 595–598.
Malahoff A (1985) Hydrothermal vents and polymetalic sulfides of the Galapagos and Gorda/Juan de Fuca Ridge systems and of submarine volcanos. Biol Soci Wash Bull 6: 19–41.
Middleton JM, Thompson RE (1986) Modeling the rise of hydrothermal plumes. Can Tech Rep Hydrogr Ocean Sci 69, 18 pp.
Riddihough RP (1980) Gorda plate motions from magnetic anomaly analysis. Earth Planetary Sci Lett 51: 163–170.
Rona PA, Klinkhammer G, Nelsen TA, Trefry JH, Elderfield H (1986) Black smokers, massive sulfides and vent biota at the Mid-Atlantic Ridge. Nature 321: 33–37.
Speiss FN, Macdonald KC, Atwater T, et al. (1980) East Pacific Rise: Hot springs and geophysical experiments. Science 207: 1421–1433.
Stommel H (1982) Is the South Pacific helium-3 plume dynamically active? Earth Planetary Sci Lett 61: 63–67.
Von Damm KL, Bischoff JL (1987) Chemistry of hydrothermal solutions from the southern Juan de Fuca Ridge. J Geophys Res 92: 11,334–11,346.
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1990 Springer-Verlag New York Inc.
About this paper
Cite this paper
Collier, R.W., Baker, E.T. (1990). Hydrography and Geochemistry of Northern Gorda Ridge. In: McMurray, G.R. (eds) Gorda Ridge. Springer, New York, NY. https://doi.org/10.1007/978-1-4612-3258-2_2
Download citation
DOI: https://doi.org/10.1007/978-1-4612-3258-2_2
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4612-7937-2
Online ISBN: 978-1-4612-3258-2
eBook Packages: Springer Book Archive