Clay Minerals on Recent Surface Estuarine Sediments from Selected Rivers of Terengganu, Malaysia

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1 Journal of Earth Sciences 1 (2015) 8-16 ISSN Betty Jones & Sisters Publishing from Selected Rivers of Terengganu, Malaysia Nor Antonina Abdullah 1, Lina Idayu Abdullah 1, Noor Azhar Mohd Shazili 1, and Shaufi Sokiman 2 1. School of Marine and Environmental Sciences, University Malaysia Terengganu, Kuala Terengganu 21030, Malaysia 2. Universiti Teknologi Petronas, Bandar Sri Iskandar, Tronoh 31750, Perak Darul Ridzuan, Malaysia Abstract: The clay mineral composition of the surface estuarine sediments from the selected estuaries of Terengganu was carried out in order to know the types of clay minerals, source of sediments and its distribution. A total of 35 clay types of samples were collected from the estuaries of Terengganu River, Kemaman River, Dungun River and Besut River. The sediments were examined using X-Ray Diffraction (XRD) method for the clay minerals present and were also run to Scanning Electron Microscope (SEM) to observe the morphology of the clays in sediments. Results show that the clay minerals found from the Holocene sediments are dominated with kaolinite and illite/muscovite and few amounts of chlorite and smectite. Observation under the SEM further show the abundance of kaolinite clay group and illite. The abundance of kaolinite and illite might be attributed to the weathering products of granite or igneous rocks which contain feldspar and mica. Granite is the dominant rock found along the East Coast of Peninsular Malaysia. Tropical climate which are warm and humid over the year will lead to excessive weathering of rocks and transformation of minerals. Thus, the estuarine sediments of the selected Terengganu rivers might generally set up from biogenic and terrigenous materials. Key words: Clay minerals, estuarine sediment, Terengganu, rivers. 1. Introduction Estuaries sediment mainly composed of marine and river sediments where continuous sedimentation process takes place. These sediments hold minerals from weathering products of rocks and minerals whether in dissolved forms and free ions or organic complexes. The grain size normally varies from very coarse grain to clay size due to mixtures of coastal and river sediments. The main instruments normally used to determine the types of clay minerals and the source rocks are X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). Sediments from sedimentary rock normally composed of quartz, feldspar, and clay minerals as their main composition [1]. Clay minerals are from different rocks as product of weathering. It can be from igneous, metamorphics, or Corresponding author: Nor Antonina Abdullah, Ph.D., research fields: sedimentology, marine pollution, mineralogy. antonina@umt.edu.my. sedimentary rocks. Different rock gives different particle size, shape, bonding, surface area, charge, characteristics and many more. Sediment from acidic base type rock will have abundance of quartz, plagioclase and alkali feldspar minerals. Johnson, 1970 pointed out that clay plays an important role in determining the physical and chemical properties of soils and also significant to understand the weathering and soil forming process. Transformation of clay minerals in the sediments are controlled by the sediment source [2]. Minerals can tell the depositional environment by studying its distribution. High levels of heavy metal indicate that the source rock is from basic igneous rock like pyroxene, peridotite and so on. Clay like illite and kaolinite suggest the derivation from crystalline rocks containing feldspar and mica from sedimentary rock [3]. However, illite is also a product of other clay-minerals synthesis like synthesis of kaolinite. Kaolinite-halloysite is a sign of fresh-water

2 9 environment deposits while montmorilonite show volcanic environment. Clay sediment has particle size of less than 2 mm in diameter with their own characteristics. The deposition of clay occurs in many environments such as volcanic deposit, river deposit, and marine deposit as a result of weathering. Clay minerals in soil generally produced from weathering of parent rocks [4]. Clay formed from weathered rocks at the surface of earth. The weathering process will change rocks original minerals to clay minerals. According to Tongkul [1], clay minerals are important minerals formed in weathering zone. Factors that influence weathering are temperature, water, living organism, climate and topography. According to Rob et al. [5], one of the reasons causing erosion are due to deforestation and development activities by human. The finer particle may end up as deposit in the estuary. The ancient sedimentary rocks containing muds, sandstones and the amount of clay in these sedimentary rocks is more than 60%. 2. Materials and Methods 2.1 Description of the Study Area Terengganu generally lies at 4 45 N E coordinate with a total area of approximately 13,035 km 2 (5,033 sq mi). Terengganu consist of few main Rivers according to district such as Terengganu River, Besut River, Dungun River and Kemaman River. As a part of Malaysia, Terengganu is also experience tropical climate which received rains and sunshine over the years. November to early January are mostly wet due to monsoon season and at this time most of fishing activities cannot be done or very slow and limited activity. The coastal areas of Terengganu directly faced the South China Sea. Age of Terengganu is believed to be a Jurassic period [6]. 2.2 Collection of Samples The surface sediment samples were collected from 35 stations from four different river estuaries using Ponar Grab. The samples were put in labeled plastic bags then brought back to the laboratory for analysis. Figure 1 shows the location of sampling sites in the study area and Table 1 shows the coordinates of sampling stations in the study areas. Table 1 Coordinates of sampling stations in the study areas. Terengganu Estuary Dungun Estuary Station Longitude Latitude Station Longitude Latitude ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' Kemaman Estuary Besut Estuary ST2a ' ' ST ' ' ST2b ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' ' ST ' '

10. Fig. 1 Location of sampling sites in the study area. 2.3 Geological Setting Peninsular Malaysia is located in the area within Southeast Asia that also experienced complex tectonic processes.

3 10. Fig. 1 Location of sampling sites in the study area. 2.3 Geological Setting Peninsular Malaysia is located in the area within Southeast Asia that also experienced complex tectonic processes. The instances of Peninsular Malaysia are the results of a clash of two continental blocks namely; Indochina plate and plate Sibumasu [7]. Metcalfe [8] in Geology Malaysia Book written by Hutchison, 2009 defines that block Sibumasu named Si (Sino which means Chinese), bu (Burma), ma (Land of Malaya) and Su (Sumatra). In the Peninsula, it was noted that more than 25% are Palaeozoic outcrop. Three main lines in Malaysia are West line, Central line and the East line which are distinguished by its stratigraphy. The study areas are located in the Eastern line where Palaeozoic sediments are Carbon to Permian age which are scattered from the East Kelantan, Terengganu, Pahang and the South of

11 Johor. This stratigraphy formed from shallow marine along with limestone and volcanic sedimentation. Figure 2 shows the geological map of Malaysia. Fig. 2 Geological map of Malaysia (Source: Mineral & Geoscience department).

4 11 Johor. This stratigraphy formed from shallow marine along with limestone and volcanic sedimentation. Figure 2 shows the geological map of Malaysia. Fig. 2 Geological map of Malaysia (Source: Mineral & Geoscience department). 3. Mechanical Techniques To study the clay mineral compositions of sediments, XRD and Scanning Electron Microscope (SEM) were used in order to identify the clay minerals present and the morphology of the specific minerals present. 3.1 X-Ray Diffraction The sediment samples were dried in room temperature and after drying, were ground to fine powder using a pestle and agate mortar. After grinding, the samples were put in a glass slides then injected to XRD machine model Bench Top X-Ray XRD. The XRD peaks were analyzed to determine the types of minerals present in the samples. 3.2 Scanning Electron Microscope (SEM) A pinch of sediments was put on steel rod and coat with gold coating before injection to the SEM. The purpose of using the S is to observe the morphology and microstructure of the clay minerals presents.

5 12 4. Results and Discussion Knowing the clay minerals in sediments, X-Ray was used. Identification of clay minerals was based on the position of the (001) series of basal reflections on the 3 XRD diagrams [9]. This evaluation was based on mineral standard data following the formula nλ = 2dsinФ. Clay normally consists of many elements but at very low concentrations (5ppm to 100ppm). Table 2 shows the results of minerals present in the study area. Results show that generally, quartz and kaolinite are the dominant minerals found in the sediments of Terengganu and Besut estuaries while illite and mica are found to be frequent in Dungun and Kemaman estuaries, On the other hand, chlorite and smectite are not found in Kemaman estuary but present as very rare to none at Terengganu, Dungun and Besut estuaries. This evaluation was based on mineral standard data with formula nλ = 2dsinФ. As can be seen in the peaks, quartz level was high because quartz is very resistant to weathering (see Table 2). Neopane & Sujakhu [10] pointed out that quartz are the most abundant minerals found in the study areas because it is very resistant to weathering and very stable mineral on earth. Other clay minerals like kaolinite and illite are also present in most of the stations which indicate a humid environment. The dominance of kaolinite in Terengganu and Besut are most likely due to the influenced of igneous rock which contain feldspar and mica that experienced weathering process from the upstream and settle down in estuary. High amount of mica is also an indication that the clay component is from marine origin because 95% of shale derived soils have mica dominant clay mineral [11]. Kaolinite most often formed by alteration of Al silicate minerals in a warm and humid environment [12]. Generally it will retain the texture and form the parent rock and having in situ alteration. This mineral group is classified as two layer clay where there is little substitution of other elements rather than Fe substitution for Al or Al substitute to Si. [12] also explain that because of limited level of substitution in Kaolins, the charge on the kaolinite layer is minimal. Wilson [13] pointed out that clay minerals found in soil of tropical climates are dominated with Kaolinite and Halloysite. Mica groups contain minerals such as illite muscovite. In XRD 10Å peaks is represent the peak for mica group. According to Fanning et al. [14], Mica minerals in soil in clay form were inherited from parent rock where they originally formed under different Pressure and temperature conditions. In the study area, illite can be found at most station for Kemaman and Dungun estuary (> more 61% observed.) Illites are interpreted to form in relatively either very cold or hot dry climate while Kaolinite formed in stronger chemical weathering [15]. This abundance of Kaolins and Illite clay shows that climate environment nowadays in Malaysia is hot and humid environment. Figure 3 shows the proportion of clay minerals found in the study area. 5. Morphological Features Based on SEM result, the morphological character/ microstructure of clay minerals in the sediment sample can be seen. Figure 4 shows morphological features of clay minerals observed in the study area. Kaolinite normally formed in acidic weathering environment like weathering of granitic rocks since it s contain lot of feldspar that will turn into kaolinite after the weathering process. Muscovite occur in basic environment [16] and have similarities with illite and formed from alteration of feldspar, biotite and muscovite. Clay minerals that can be observed under SEM machine are kaolinite, halloysite, muscovite, quartz. Kaolinite is characterized from layered structure, halloysite with tubular structure, and illite is like ropes structure. Due to mixing of different type of minerals of estuary sediments, clay observations are quite hard and

6 13 taking time to identify the minerals. However there difficulties in identify the minerals due to the unfocused outcrop and the sample not undergo purification (see Figure 5). Table 2 Minerals present in sediments samples from four selected rivers in Terengganu. Quartz Kaolinite Mica/Illite chlorite smectite Terengganu estuary ST ST ST ST ST ST ST ST Dungun estuary ST ST ST ST ST ST ST ST Kemaman estuary ST ST2a ST2b ST ST ST ST Besut estuary ST ST ST ST ST ST ST Note: +++ dominant mineral (> 50% observed), ++ frequent (21%-50% observed), + few or less (< 21% observed), - none.

7 14 Fig. 3 Pie chart of clay minerals found in four estuaries of the study area.

8 15 Fig. 4 Example of XRD peaks (Kemaman estuary, station 5). Fig.5 Clay mineral morphology observed under SEM in the study areas. 6. Conclusion As a conclusion, the clay minerals in estuaries of selected rivers in Terengganu are dominated with kaolinite followed by illite which might be due to the humid environment and rapid weathering process that occurred. These clay minerals are the weathering products of granitic rocks from the upstream transported by rivers and accumulate in the estuaries.

9 16 References [1] F. Tongkul, Sedimentology, 1st ed., Penerbit Universiti Kebangsaan Malaysia, 2000, pp. 25. [2] S. Sabiham, S. Basuki, Study on Peat in the Coastal Plains of Sumatra and Borneo Part II: The Clay Mineralogical Composition of Sediments in Coastal Plains of Jambi and South Kalimantan, Southeast Asian Studies 27 (1989). [3] A.R. Chaudri, M. Singh, Clay minerals as climate change indicators, American Journal of Climate Change 1 (2012) [4] Z.F. LIU, H. WANG, W.S. Hantoro, E. Sathiamurthy, C. Colin, Climatic and tectonic controls on chemical weathering in tropical Southeast Asia (Malay Peninsula, Borneo, and Sumatra), Chemical Geology 291 (2012) [5] J.G. Robinson, E.L. Bennett (Eds.), Hunting for sustain-ability in tropical forests. Columbia University Press, Columbia, [6] C.S. Hutchison, D.N.K. Tan (Eds.), Geology of Peninsular Malaysia, University of Malaya & Geological Society of Malaysia, [7] C.S. Hutchison, Geological evolution of South East Asia. Oxford Monographs on Geology and Geophysics, Clarendon Press, Oxford, 13 (1989) 368. [8] I. Metcalfe, Stratigraphy, paleontology and paleogeography of the Carboniferous od Southeast Asia. France Geology Memoir 147 (1984) [9] Z.F. LIU, Y.L. Zhao, C. Colin, F.P. Siringan, Q. WU, Chemical weathering in Luzon, Philippines from clay mineralogy and major-element geochemistry of river sediments, Applied Geochemistry 11 (24) (2009) [10] H.P. Neopane, S. Sujakhu, Particle Size Distribution and Mineral Analysis of Sediments in Nepalese Hydropower Plant : A Case Study of Jhimruk Hydropower Plant, Engineering and Technology 9(1) (2013) [11] L.J. Johnson, Clay minerals in Pennsylvania soils: Relation to lithology of the parent rock and other factors I. Clay and clay minerals 18 (1970) [12] H.H. Murray, Applied clay mineralogy today and tomorrow, Clay minerals 34 (1999) [13] M.J. Wilson, The origin and formation of clay mineral in soils: Past, present and future perspectives, Clay minerals 34 (1999) [14] D.S. Fanning, V.Z. Keramidas, M.A. E1-Desoky, Micas, in J.B. Dixon, S.B. Weed (Eds.), Minerals in Soil Environments, Soil Sci. Soc. Madison, Wisconsin, America, 1989, pp [15] H. WANG, Z.F. LIU, E. Sathiamurthy, C. Colin, J.R. LI, Y.L. ZHAO, Chemical weathering in Malay Peninsula and North Borneo: Clay mineralogy and element geochemistry of river surface, Earth Science 54 (2011) [16] R.E. Newnham, H.D. Megaw, The Crystal Structure of Celsian Barium Feldspar, Acta Cryst., 1960, vol. 13, part 4, pp

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