Browsing by Author "Adikaram, A.M.N.M."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Depositional History of Sediments in Eastern Lagoons of Sri Lanka: Sedimentological and Mineralogical Evidences
    (Uva Wellassa University of Sri Lanka, 2018) Megasooriyal, M.M.T.I.; Adikaram, A.M.N.M.; Hewathilake, H.P.T.S.
    Characteristics of sediments and minerals are useful in identification of paleodepositional environments. Specially, clay mineralogy shows the specific environmental conditions that are related to the marine or terrestrial environments. Present study used sedimentological and mineralogical characteristics of recent age sediments of Batticaloa lagoon and Kiran lagoon to interpret the depositional environments. Four sediment core samples with an average height of 1 m were collected from both lagoons and analyzed for temporal grain size distributions using mechanical sieving techniques. Vertical profiles of sand and clay mineralogy were investigated by grain counting technique, X-ray diffraction and Fourier-transform infrared spectroscopy. Medium size sediments are the dominant type indicating prevailed moderate energy conditions for the history. Several coarse grain events are recorded in cores which might be originated from storms. Statistical parameters of sediment grain size and Quartz-Feldspar-Lithic fragments triangular diagram of sands show matured riverine continental origin for the depositional history. Main clay minerals of the depositions include kaolinites, smectites, illites and chlorites. Clay mineral profile also confirms the continuous sedimentation history for the past centuries. The results of the study conclude that the recent history of the sediment depositions in eastern lagoons have not been affected by considerable environmental changes except some coarse events such as high energy storms.
  • Thumbnail Image
    Item
    Geochemical Characterization of Magnetite Ore Deposit in Buttala, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2019) Athisinghe, A.M.J.N.; Hewathilake, H.P.T.S.; Adikaram, A.M.N.M.
    Sri Lanka comprises of a fairly large number of valuable mineral deposits. However, most of these deposits have not yet been scientifically investigated, in terms of their origin, grade, mineralogy, quality and the quantity. Iron ore deposits of Sri Lanka are divided into three categories as magnetite deposits, hydrated iron oxide deposits and coppermagnetite type deposits. The largest magnetite deposit of the country is located at Palawatte, Buttala in Uva province. The origin, quality and the quantity of the Buttala magnetite deposit (BMD) is still debatable. Therefore, present study focused to interpret the geochemical characteristics in order to predict the possible sources for the origin of BMD. Rock samples were collected from the pre-determined locations in BMD area. Representative magnetite bearing rock samples and country rock samples were collected mainly from fresh outcrops available at the surface. A detailed geochemical analysis was conducted by X-ray fluorescence (XRF) spectroscopy. The results of major oxides indicated high content of iron (>80%) with minor amounts of SiO2 (7.02%), Al2O3 (5.98%), TiO2 (3.22%), MgO (2.82%), K2O (0.22%), CaO (0.12%) and MnO (0.08%). The spatial distribution plots of trace elements and major elements indicate the mineralization is localized to the hummock of the study area. The depleted concentrations of elements such as Ti and Zr that are considered relatively immobile in hydrothermal fluids suggests the involvement of hydrothermal processes to the formation of BMD. Further, it is recommended a detailed petrographic analysis in order to confirm the hydrothermal origin of the BMD.