Geochemical Variations of Prospective Heavy Mineral Deposits Bordering the Coastline of Sri Lanka
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Date
2021
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Uva Wellassa University of Sri Lanka
Abstract
Heavy minerals with a specific gravity greater than 2.9 g/cm3 such as ilmenite (FeTiO3), rutile
(TiO2), leucoxene (altered ilmenite), zircon (ZrSiO4), monazite ((Ce,La,Nd,Th)PO4), garnet
((Ca,Mg,Fe,Mn)3(Al,Fe,Mn,V,Cr)2(SiO4)3), sillimanite (Al2SiO5), and magnetite (Fe3O4) have gained
global attention as a result of modern technological advances. In this regard, the mining and
processing of these heavy minerals are a timely requirement to uplift the mineral industry and the
economy of Sri Lanka. Therefore, the objective of this study is to investigate the geochemical
variations of prospective heavy mineral deposits along the coastline in order to identify locations with
economically significant concentrations of heavy minerals. Field excursions were carried out to
identify the potential of heavy mineral placers in Sri Lanka. Sediment samples were collected from
ten locations covering both the shoreline and raised beaches. X-ray fluorescence (XRF) analysis was
used to determine the major and trace element compositions of sediments. When compared to
average Upper Continental Crust (UCC) values, major and trace element variations show the
enrichments of TiO2, Fe2O3, La, Ce, Zr, Cr, Nb, Th, and V. The abundance of TiO2, Fe2O3, and Zr,
and visual examination of samples suggest the presence of higher concentrations of heavy minerals
such as ilmenite, rutile, and zircon in the prospective locations. Moreover, the abundance of trace
elements such as La, Ce, and Th implies the presence of rare earth elements (REEs) bearing heavy
minerals such as monazite and zircon. In contrast, major elements (Al2O3, Na2O, and K2O) and large-
ion lithophile elements (Ba and Rb) were significantly depleted compared to UCC values. Based on
the XRF data and visual examination, it can be concluded that all the studied locations such as
Verugal, Dickwella, Kosgoda, Payagala, Beruwala, Kalutara, Dharga Town, and Aruwakkalu can be
identified as potential sites for heavy mineral placers. Finally, proper quantification is required to
estimate economic grade and to determine mining feasibility.
Keywords: Heavy minerals; Geochemical variation; Economic concentrations; Coastline of Sri Lanka
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Keywords
Materials Sciences, Mineral Sciences, Geochemistry, Geochemical, Coastline of Sri Lanka, Applied Earth Sciences