Contrast in manganese nodule distribution on either side of 79° E fracture zone in Central Indian Basin

Abstract

Seabed topography is one of the prime factors in controlling the distribution of manganese nodules. Study of the nodule abundance on either side of the 79°E fracture zone in the Central Indian Basin (identified from multibeam bathymetric data) shows that the western side of the fracture zone has higher average nodule abundances. The eastern (downthrown) side of the fracture zone has less nodule abundance, and the seafloor is very smooth with a thick sediment layer. The sedimentation rates on the downthrown side are higher because of the sediment input from the northeastern direction and the fracture zone wall acting as a conduit for sediment transport. Immediately after the fracture zone on the eastern side, the seafloor is flat because of the sediment being deposited on the foot of the fracture zone. Also, the western flank seafloor has higher relief than the eastern flank. However, the metal content in nodules on either side does not show marked variations.