Unknown
PANGAEA
In:
Supplement to: Melson, William G (1968): Preliminary results of a geophysical study of portions of the Juan de Fuca Ridge and Blanco Fracture zone: a study performed aboard the USC & GS ship Oceanographer, October 15-26, 1968. ESSA technical memorandum C & GSTM; U.S. Dept. of Commerce, Environmental Science Services Administration, Coast and Geodetic Survey, Rockville, Md, 6
Publication Date:
2023-08-28
Description:
Preliminary results of a 14-day cruise of the USC&GS ship Oceanographer to the area near the junction of Juan de Fuca Ridge and the Blanco Fracture Zone are reported. About 10 full days of bathymetry (using a narrow beam transducer), magnetic, and gravity were completed. Fifteen dredges were attempted, 13 were successful. A striking bathymetric symmetry up to 15 miles on each side of the axis was found on five crossings of the Juan de Fuca Ridge. This symmetry extends at least 17 and possibly 30 nautical miles along the Ridge axis. Relief features, ranging from 100 to 20 fathoms, were found to correlate with similar features across the axis. This bathymetric symmetry is more striking than the magnetic symmetry and is an independent line of evidence in support of sea-floor spreading. A small, median perched graben along portions of the Juan de Fuca Ridge axis is floored by a very recent basaltic flows which have unusual surface structures.
Keywords:
Deposit type; DEPTH, sediment/rock; Description; Dredge; DRG; Elevation of event; Event label; Identification; Latitude of event; Longitude of event; Method/Device of event; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; OC68; Oceanographer; OCNGR68; OCNGR68-D10; OCNGR68-D12; OCNGR68-D14; OCNGR68-D15; OCNGR68-D9; Pacific Ocean; Position; Quantity of deposit; Size; Substrate type; Visual description
Type:
Dataset
Format:
text/tab-separated-values, 30 data points
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