Characterization and geochemistry of gold deposits of Peninsular Malaysia

摘要

The electronprobe microanalyzer (EPMA)was used as a tool to study gold from the Raub-Tersang-Selinsing-Penjom, Rusila-Lubuk Mandi, and Jeli-Sokor areas in Peninsular Malaysia with the aim of characterizing the various primary and alluvial gold deposits and tracing the alluvial gold grains to their primary sources. In Terengganu, at Rusila-Lubuk Mandi it was demonstrated that the size of the alluvial gold grains nearest to the primary gold veins average 3.05 mm long and 2.5 mm wide while those furthest away tend to average to about 0.81 mm long and 0.7 mmwide. In the Raub-Tersang-Selinsing-Penjom area in Pahang, the alluvial samples from Sg. Ulu Tersang, a river in SE Selinsing and Sg. Terenggun and tailings samples from Kg. Pulai (Tersang) and NW Penjom generally show a bimodal distribution with dominant lengths averaging 0.4 mm for the major distribution and 1.0 mm for the minor. Gold grain size studies show that the samples from Sokor are fine grained which range from 0.1-0.3 mm for the lengths and the widths of the samples collected from Sg. Tui and Sg. Sokor, whereas the grain size of the samples from Jeli are bigger with an average length of 0.7 mm for samples from Sg. Pergau and an average particle size of 0.8 mm long and 0.4 mm wide for samples from Sg. Tadoh. As a whole, the samples from the Jeli area comprise grain sizes that are larger when compared to the samples from Sokor area. Geochemical EPMA analysis of the gold grains revealed that silver is present in the gold in different amounts from different areas. It can be demonstrated that fineness is a useful character for tracing the primary sources of gold from the panned alluvial gold samples further downstream.Preliminary results showed that the primary and alluvial gold and silver contents at Rusila-Lubuk Mandi are more-or-less the same suggesting that alluvial gold grains come solely from the primary mineralisation at Bukit Lubuk Mandi while the fineness at the Bukit Koman-Tersang-Selinsing-Penjom and Jeli-Sokor areas are different and distinctive of each locality. EPMA characterisation of the gold for the various localities in Peninsular Malaysia is very useful in tracing the primary source areas.