Geophysical description of a Pacific Ocean Seamount

Abstract

In February 1965 the U.S. Coast and Geodetic Survey ship Pioneer obtained intensive bathymetric, magnetic, and gravity data over the previously uncharted Chautauqua seamount, located 155 km west of Kauai. Detailed analyses of the data support the following interpretations: Chautauqua seamount lies on the flank of the Hawaiian ridge and is one member of a 230-km-long chain of seamounts oriented roughly 30° from normal to the trend of the ridge. It rises at a nominal slope of 15° from a surrounding depth of 4500 meters to a least depth of 1785 meters. Although the uppermost part is normally polarized, the bulk of the seamount appears to be reversely polarized, with the contrast in magnetic properties extending to a depth of about 1 km beneath the sea floor. The mean density of Chautauqua seamount is 2.5 g/cc. Evidence of block faulting during development is seen in the seamount's gravity field. No definite conclusions can be drawn about the age of Chautauqua seamount. The reversed magnetization could have been acquired during the Matuyama reversed polarity epoch (0.85 ± 0.15 to 2.4 ± 0.1 million years ago) or during some earlier reversed epoch.