Bulletin of the Geological Society of Malaysia, Volume 17, Dec.1984, pp. 283 – 306
Applied Geology Department, Postgraduate Training in Mineral Exploration, Arts and Science University Rangoon, Burma
2Present address Directorate of Geological Survey and Exploration, Kanbe, Rangoon, Burma
ABSTRACT: The Theingon Pb-Zn deposit is located near Bawsaing, Southern Shan State, Burma. The Theingon deposit is comparable to the principal Mississippi-Valley-type deposits of Heyl et. al. (1974) in many respects such as host rock stratigraphy, structural setting of the orebody, mineralogy and ore metal zonation. The Theingon Pb-Zn mineralization occurs within the carbonate rocks of the Wunbye Formation (Lower to Middle Ordovician). The orebody is localised in a clay-filled solution channel along a limb of an east dipping small overturned anticline. The ore assemblages are essentially of galena with minor mounts of sphalerite, tetrahedrite-tennantite, digenite, chalcopyrite, coveIite, argentite and pyrite. Following the crude mineralogical zonation in the Theingon Mine, quantitative picture of the ore elements (Pb, Zn and Cu) contents in the carbonate host rocks within the orebody exhibited a broad, but distinct overlapping vertical zonation, the copper (more than 100 ppm) being commonly concentrated at the lower part of the orebody while zinc (more than 1000 ppm) and lead (more than 2000 ppm) restricted to the upper part of the orebody.
Present geologic, mineralogic and geochemical evidences combined with accumulation of ore minerals embedded in a yellow clay-filled channel in the carbonate rocks lend support to the conclusion that the Theingon Pb-Zn mineralisation is epigenetic in origin and can be explained by the combination of magmatic-and meteoric hydrothermal circulation (White, 1974).
Ore metals contents in the carbonale host rocks in the Theingon-Mine are found generally and progressively increased towards the mineralised zones. This ore elements variation suggests, though does not prove, that the ore constituents have been leached by ground water circulated relatively deep into the adjacent Sedimentary Paleozoic beds. Further isotopic studies are needed to ascertain the source and sources of ore metals and fluids.