Browsing by Author "Edwar, Rufli"

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    Proses Deposisi Sedimen Di Perairan Dompak Provinsi Kepulauan Riau Indonesia
    (2014-11-09) Amirul, Mukminin; Rifardi; Edwar, Rufli
    The purpose of this study is to claiify relationship between sedimentation process including accumulation rate total suspended solid and grain size-sediment, and anthropogenic activities. Sediment samples consist of accumulation rate, total suspended solid and surface sediments were collected from 4 stasions in the dompak sea, Riau Archipelago province, Indonesia in July to August 2008. Present work revealed that station 4 is characterized by the bigbest accumulation rate (2.21 ml /cm2/ day ), very fine sand and very poorly sorted sediment, under the influence of bauxite mining supplied terrigeneous sediments. Contrastingly, station 3 is occupied by the lowest accumulation rate accumulation rate (0.48 ml/cm2/day), high suspended sediment (2 mg/l) , and coarse silt, under the influence of rather stagnant water masses. Rather high accumulation rate (0.72 ml/ cm2/day),coarse silt and well sorted sediments are found in station 1 which affected by waters transportation and binterland development activities. The sediment of station 2 is characterized by accumulation rate (0.55 ml/cm2 / day), fine sand and moderately well sorted sediment. The sediment is assumed to be derived from surrounding areas which is trapped by mangrove . the result at the probability calculation sedimentation occurring in Dompak Sea is affedted by anthropogenic activities (p<0.05) in addition, natural process play also importance role on the sedimentation. Keywords : sedimentation, anthropogenic activities, natural process, Dompak Sea
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    Sediment Composition As Vertical In Dumai Coastal Waters
    (2014-11-09) Nunung, Fidiatur R; Rifardi; Edwar, Rufli
    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
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    Sedimentological Aspects and Relative Sedimentation Rates in the Dumai Coastal Waters, Riau Province Indonesia
    (2014-11-09) Rifardi; Edwar, Rufli; Syahminan; Suwarni; Renti, Butar Butar; Nunung, Fidiatur
    The main purpose of this study is to reveal the sedimentary enviroments based on sediment characteristics and relative sedimentation rates. The obtained data are all based on analysis results of core samples taken from the Dumai Coastal Waters located off the north coast of Dumai City Indonesia. Bottom sediment samples were collected at 7 stations in the waters using gravity corer in March 2011. The samples were used for mechanical grain size analysis, ignition loss method, and bulk chemical analysis. In addition, the topmost one centimeter of core samples, which approximately 10 cc of wet sediments, was utilized for benthic foraminiferal study, namely, the study of of L/Tl values to infer the relative sedimentation rates. The Dumai Coastal Waters, Riau Province Indonesia is subdivided into three areas based on the general trend of sediment characteristics and relative sedimentation rates as following: 1) the central part of the waters is characterized by coarse-grained sediments, high relative sedimentation rates and dominantly terrigeneous sediments which under influence of rather strong tidal currents, 2) the eastern and western parts of the waters are characterized by relatively coarse-grained sediments, rather high relative sedimentation rates and relatively high biogeneous sediments which are influenced by longshore currents, and 3) the area off the coast (central part) is characterized by fine-grained sediments, the highest relative sedimentation rates. The area correspond to the boundary between the waters masses derived from Rupat Strait and of from Dumai Waters and is under influence of weak tidal current The distribution of crude oil content in sediments indicate that study area under influence of tidal and longshore currents. Judging from the distribution pattern of crude oil content in sediments, sediments polluted by crude oil were transported northwestward and northeastward by longshore currents and spread toward north by tidal currents, of the Dumai Coastal Waters. Key words : sedimentary enviroments, relative sedimentation rates, Dumai Coastal Waters