Geophysical and Sedimentological Characteristics of

Abstract: Lomilik Seamount in the west Pacific was seismically surveyed and photographed to illuminate the bottom topography, the condition of manganese crust, and the characteristics of sedimentary environment. Lomilik Seamount has a NW-SE elongated bottom topography with steep slopes in the NE-SW direction part. Even though the steep slopes of the seamount are devoid of deposits, the summit area and gentle slope of the seamount are covered with thick deposits. The seismic data indicate that Lomilik Seamount is a flat-topped and step-faulted guyot of volcanic origin. Deep-sea camera photographs show that much of the seafloor is rippled in symmetrical and asymmetrical patterns. The traces of biological activity were distinct on gentle seafloor suggesting the low-energy bottom conditions. Some photographs also show outcrops encrusted with manganese crusts. Sedimentary environments in the Lomilik Seamount appear have been governed by regional morphology and strong bottom current. Key words: (Lomilik seamount), (bottom topography), (Deep-sea camera photographs) 1. 1,000 m 6 % (Jordan et al. 1983)