Characterization of Langkawi Black Sand as Natural Tracer for Sediment Transport

Black sand is commonly available at area where there are volcanic activities. Black sand is not common in Malaysia, as Malaysia is situated outside the ring of fire, thus the only place black sand is available is at Langkawi Island which make the only non-volcanic black sand beach. Black sand at Pasir Hitam, Langkawi Island is located at the beach which this mineral sand deposits stretch about 2 km in length. The sand is visually blackish due to abundance of ilmenite (FeTiO₃). According to literature, the black sand deposits in Pasir Hitam beach are rich in heavy minerals, the content being 86 % tourmaline, 12 % ilmenite and trace amounts of monazite, zircon, rutile, alanite and xenotime, known for their content of rare earth elements, also including uranium and thorium. In particular, monazite and zircon in black beach sand are known to contain elevated levels of natural radioactivity from the U-238 and Th-232 series radionuclides. For Langkawi black sand, the mean concentrations of Ra-226 and Ra-228 in black sand of Pasir Hitam beach were 1.0 ± 0.12 Bq/g and 0.53 ± 0.085 Bq/g respectively. It was also reported that about 22 elements were detected in Langkawi black sand. (author)