SEDIMENT STRATIGRAPHY IN COASTAL WATERS OF WESTERN PART OF RUPAT STRAIT RIAU PROVINCE

Abstract

The study aims to describe Lithostratigraphy based on vertical
distribution of sediment fractions in western part of Rupat Strait. The sediment
samples were taken in May 2014 from 9 sampling points and 3 stations by using
gravity cores. The position of the sampling point was determined by using
purposive sampling method. Each sample obtained from core samples was
divided into 3. All the sediment samples were analyzed by using mechanical
analysis. The analysis showed that the sediment in the area was dominated by the
sand fraction with percentages ranging from 58.59 to 98.31 % with the highest
percentage was located at the sampling point 2 middle layer and the lowest at 5
sampling points lower layers. Sediment grain size did not undergo significant
difference vertically. At station 1 the changes in sediment grain size was only
found at the sampling point 3 middle layer. Sediment grain size at station 2
changed at the sampling point 4 middle layer and the top layer 6 sampling points
while the grain size of the sediment contained in station 3 occurs at the sampling
point 7 layers above and below the layer 9 sampling points. Based on cluster
analysis the sediment layer of western part of Rupat strait IV can be divided into
groups based on five characteristics of sediments and in each group showed that
the difference was not significant.
Keywords : Stratigraphy, Sedimentary, Rupat Strait