Textural characteristics of shelf surface sediments of southeast coast of India

Abstract

Present study consists analyses of surface sediment samples collected from the continental shelf region at depths of

30 m, 50 m, 75 m, 100 m, 150 m and 200 m . Six types of sediment textures were found (coarse sand, medium sand, fine sand, coarse silt, medium silt and fine slit). Particle diameter decreased with increasing depth. The phi mean ranged between 0.466φ<span style="font-size:9.0pt; mso-bidi-font-family:MSTT31c650"> (coarse sand - Tammenapatanam 75 m) and <span style="font-size:9.0pt;mso-bidi-font-family: MSTT31c650">7.8306φ<span style="font-size:9.0pt;mso-bidi-font-family:MSTT31c650"> (fine silt -Singarayakonda 75 m). Flow from Krishna river was found to influence the particle diameter of sediment in Singarayakonda where the sediment was silty from 50 m depth onwards whereas in the other transects where the river flow was comparatively low, the sediment was silty only at 200 m depth. Silty sediments were found very well sorted. Negative skweness values observed in the middle depths indicated the transition zones. Sediments with leptokurtic distribution indicate deposits with a high degree of textural maturity and reworking. The first percentile and median of size distribution pattern reflects suspension and rolling mode of transportational history, indicating the complexity in the hydrodynamic processes operating in the study area.

</span></span></span>