Abstract:
The research was conducted in March to April 2011 in Dumai coastal waters. The purpose
of this research was to understand the materials composing the sediment profiles vertically.
Field survey method was applied with location of study consisting 7 stations. Sediment
samples were taken by using the Gravity core, in every station a length of 12 cm was cut and
divided into 5 layers with thickness of 1 cm. Sediment sample obtained from field was
analyzed in laboratory by using sand composition analysis. The result showed that sediment
composition found consisting of lithogenous sediment (rock fragment, mica and quartz) and
biogenous (plant fibers, foraminifera and mollusc). The vertical composition difference was
not clear. Rock fragment dominated at every layer in stations north and west sides of PT.
Pertamina UP II Dumai indicate rock fragment supply proceed from erosion of land and
abrasion caused by tidal current and wave. In stations of east sides from PT. Pertamina UP II
Dumai the upper and lower layers dominated by plant fibers that could be coming from
mangrove decomposition in this area. The overall results indicate that all sediment materials
in the area were derived from the similar source, thus reflecting the small differences in the
sediment material.
Keyword : composition, vertical sediment, Dumai coast
