Major off-axis hydrothermal activity on the northern Gorda Ridge

Journal Article · Fri Jun 01 04:00:00 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), Journal Name: Geology; (USA) Vol. 18:6; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

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