Tin and gold mineralizations in Peninsular Malaysia and their relationships to the tectonic development

Abstract

Tin and gold mineralizations in Peninsular Malaysia occur as several juxtaposed and overlapping belts. That the tin deposits are genetically related to the Late Triassic S-type granites is indisputable. The source of gold is probably from the oceanic lithospheric or lower crustal materials. It is postulated that the gold was extracted from these materials which were metamorphosed when they were subducted. Tectonically, Peninsular Malaysia can be divided into a Western Block with a relatively thicker cratonized upper crust and an Eastern Block which is composed of an accretionary complex and the Timur and Tenggara Terranes. It is postulated that a westward subduction of the oceanic lithosphere beneath the Western Block began in the Late Carboniferous. This westward dipping Benioff zone migrated eastwards in several leaps. Continental fragments rafted on the westward moving oceanic plate were brought to collide with the accretional complex which had developed on the eastern margin of the Western Block. This brought about the generation of S-type granites largely in the Western Block and the Timur and Tenggara Terranes. Anatexis of portions of the upper crust with anomalous Sn content gave rise to specialized granites which accounted for the two belts of tin deposits. The westward subduction of the oceanic lithospheric materials is postulated to have released gold-bearing fluids which migrated upwards along deep-seated fractures, or preceded or followed paths taken by volcanic magmas to the surface to form the gold deposits. This explains the presence of structurally controlled gold deposits forming well-defined belts. Gold mineralizing fluids which preceded or followed paths taken by volcanic magmas deposited gold in massive sulphides, feeder zones and vein swarms, which were distributed over a broad belt.