Bulletin of the Geological Society of Malaysia, Volume 24, Oct.1989, pp. 1 – 12
Jabatan Geologi, Universiti Kebangsaan Malaysia, Bangi
Abstract: Over a hundred samples of alluvial concentrates, taken from mines and streams that represent the various tinfields of Peninsular Malaysia have been examined. Concentrates .from known pegmatitic areas show abundance of columbite-tantalite, the hydrothermal concentrates with a variety of minerals from sulphides to oxides and pyrometasomtic concentrates with magnetite. The form of individual mineral grains shows variation and they are also related to the types of tin deposit. Cassiterite in particular shows a variety of forms. In addition to the common tetragonal habit, pegmatitic cassiterite from Semiling and Bakri have peculiar shapes of i) squat bipyramid ii) wedge terminated prism and iii) rhombohedral pyramid-terminated prism. Wood-tin was found in the east coast tinfields. Characteristics of other detrital minerals are also discussed. These detrital mineral characteristics are useful guides that could be used to characterise the various tinfields of Peninsular Malaysia, in view of the difficulty in obtaining fresh primary ore samples due to the deep tropical weathering conditions.
Abstrak: Lebih daripada satu ratus sampel padat aluvium, yang diperolehi daripada lombong-lombong dan anak-anak sungai yang mewakil kawasan-kawasan timah Semenanjung Malaysia telah diteliti. Sampel padatan daripada kawasan pegmatite mengandungi kolumbit-tantalit, padatan hidrotermal mengandungi aneka mineral dari sulfida hingga oksida dan padatan pirometasoma pula mengandungi magnetit. Bentuk butiran mineral individu memperlihatkan kepelbagaian dan berkait rapat dengan jenis-jenis longgokan bijih timah. Kasiterit khususnya menunjukkan pelbagai bentuk. Selain daripada tabiat tetragonnya yang biasa, kasisterit pegmatit daripada Semiling dan Bakri mempunyai bentuk-bentuk yang aneh, iaitu i) dwipiramid cakah ii) prisma berhujung baji dan iii) prisma berhujung piramid rombus. Timah kayu di jumpai di kawasan timah pantai timur. Ciri-ciri mineral gersik lain juga dibincangkan, dan ciri-ciri tersebut berguna untuk mencirikan kawasan-kawasan timah Semenanjung Malaysia, memandangkan sampel bijih yang segar amat sukar diperolehi disebabkan oleh keadaan luluhawa tropika yang begitu mendalam.
https://doi.org/10.7186/bgsm24198901
