Major off-axis hydrothermal activity on the northern Gorda Ridge

Journal Article · Fri Jun 01 00:00:00 EDT 1990 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1990)018<0493:MOAHAO>2.3.CO;2· OSTI ID:6419211

Rona, P A ^[1]; Denlinger, R P ^[2]; Fisk, M R; Howard, K J; Taghon, G L ^[3]; Klitgord, K D ^[4]; McClain, J S ^[5]; McMurray, G R ^[6]; Wiltshire, J C ^[7]

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1. NOAA/AOML, Miami, FL (USA)
2. Univ. of Washington, Seattle (USA)
3. Oregon State Univ., Corvallis (USA)
4. Geological Survey, Woods Hole, MA (USA)
5. Univ. of California, Davis (USA)
6. Department of Geology and Mineral Industries, Portland, OR (USA)
7. Univ. of Hawaii, Honolulu (USA)

The first hydrothermal field on the northern Gorda Ridge, the Sea Cliff hydrothermal field, was discovered and geologic controls of hydrothermal activity in the rift valley were investigated on a dive series using the DSV Sea Cliff. The Sea Cliff hydrothermal field was discovered where predicted at the intersection of axis-oblique and axis-parallel faults at the south end of a linear ridge at mid-depth (2700 m) on on the east wall. Preliminary mapping and sampling of the field reveal: a setting nested on nearly sediment-free fault blocks 300 m above the rift valley floor 2.6 km from the axis; a spectrum of venting types from seeps to black smokers; high conductive heat flow estimated to be equivalent to the convective flux of multiple black smokers through areas of the sea floor sealed by a caprock of clastic breccia primarily derived from basalt with siliceous cement and barite pore fillings; and a vent biota with Juan de Fuca Ridge affinities. These findings demonstrate the importance of off-axis hydrothermal activity and the role of the intersection of tectonic lineations in controlling hydrothermal sites at sea-floor spreading centers.

• OSTI ID: 6419211
• Journal Information: Geology; (USA), Vol. 18:6; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
HYDROTHERMAL SYSTEMS
GEOTHERMAL EXPLORATION
PACIFIC OCEAN
CAP ROCK
DEPTH
GEOLOGIC FAULTS
GEOLOGY
GEOTHERMAL FLUIDS
HEAT FLOW
MAPPING
OREGON
RIFT ZONES
SAMPLING
SEA BED
SEA-FLOOR SPREADING
TECTONICS
DIMENSIONS
ENERGY SYSTEMS
EXPLORATION
FEDERAL REGION X
FLUIDS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOTHERMAL SYSTEMS
NORTH AMERICA
SEAS
SURFACE WATERS
USA
150200* - Geology &amp; Hydrology of Geothermal Systems