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SECOND GOLD BELT DEPOSIT IN TERSANG, PAHANG OF PENINSULAR MALAYSIA

Ahmad Fauzan Yusoff and Jasmi Hafiz Abdul Aziz

Department of Geology, University of Malaya, 50603 Kuala Lumpur

The Tersang area is located in the northwestern part of Pahang, approximately 14 km north of Raub town. This area is bounded approximately by latitudes 3 53’ N to 4 02’ N and by longitudes 101 47’E to 101 53’E (Figure 1.1). The gold samples has been taken from Tersang Hill Mine and noticed to be a primary gold. This study was determined by using Plane Polarize Light (PPL), BSE images, EPMA EDS scan and EPMA X – ray map.

The Tersang Hill Mine is located on part of a north-south trending ridge where underlain by weathered interbeds of arenaceous and argillaceous rocks. The arenaceous rock is fine grained tuffaceous sandstone while the argillaceous rock is laminated shale. The bedding at Tersang Hill Mine generally trend between 070 and 100, while the dip is steep, mainly to the south.

The type of gold mineralization occurs in the Tersang Hill Mine are sheeted quartz veins and stockwork system. The quartz veins in the area generally trend from 070 to 140 , where the thickness is more than 1 m thick for all major veins and 20 to 100 cm for the majority veins. Majority of the veins are dipping from 50 to 70 to the north and northeast, while some are dipping 40 to 60 the southwest. The major veins are generally persistent over a distance of 50 m, although the majorities extend laterally between 10 and 50 m.

The brecciated wall rock in the veins and the displacement of veins by latter veins indicate the presence of fault and joints process even the sense of movement is not clear. Mineralization fluid is provided by these fractures and when the temperature drops, the deposition of gold occurred. The quartz – gold bearing veins occur as thin veins and stringers which branch from quartz sulphide veins.

Study on petrographic show the gold is angular to sub – angular roundness and discoidal to sub – prismoidal sphericity (Figure 1.2). Gold in the quartz veins are mainly associated with pyrite (FeS2), chalcopyrite (CuFeS2), cinnabar (HgS), iron oxides (Fe,O), cassiterite (SnO2), ilmenite (FeTiO3), rutile (TiO2), arsenopyrite (FeAsS), monazite [(Ce, La, Nd, Th) PO4], zircon (ZrSiO4), associated silicates (Si,Al,O) and valentinite Sb2O3. Occurrence of valentinite is reported for the first time in this area. The valentinite grains occur at the interstitial spaces in iron oxides and quartz, and this occurrence is confirmed by the EPMA X-ray map. In general, the gold occurs is fine grains and aggregates, and as fine dissemination within, and infilling fracture and interstices of quartz veins.

The variable quantities of Ag, Pb, Sb, Te, Cu, Ad, Fe and Si that found together with gold indicate of variation in this area. Data from EPMA quantities show the primary gold composition in the Tersang Hill Mine ranges from 87.97 wt% to 98.70 wt%. These gold samples also show that there are three model fineness values for primary gold in this area, namely, 979, 961 and 882 where it is quite high in gold composition. This modal fineness values suggest at least three different episodes of gold mineralization which could be related to the three vein directions.

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EPMA quantitative analysis shows nine elements where found associated in gold composition. These elements are gold (Au), silver (Ag), lead (Pb), antimony (Sb), tellurium (Te), copper (Cu), aluminium (Al), iron (Fe) and silica (Si) (Table 1). The high concentrations among the others are gold (Au) and silver (Ag). The highest concentration for gold (Au) and silver (Au) are 98.70 wt% and 11.91 wt% respectively. While the lowest concentration for gold (Au) and silver (Au) are 87.97 wt % and 1.10 wt %. The rest of elements have concentration range from0.22 wt% to 0.10 wt % and also have 0.00 wt % of elements at certain part of particular area where the sample is taken. Although the very least of concentration among the others sample is tellurium (Te).

Figure 1.1: Geological map of the Tersang Hill Mine area, Pahang (Khoo, 1988).

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Il

Ru Zi

IlAu

Fe

Qtz

Figure 1.2: Photomicrograph of concentrates from Tersang showing the presence of gold (Au) associated with ilmenite (Il), rutile (Ru), zircon (Zi), iron oxides (Fe) and quartz (Qtz). Gold are subangular. Sample Tersang 1.

Plane polarized light. Scale bar is 100 µm.

Table 1: Normalized EPMA quantitative analysis for gold samples from Tersang Hill (wt %).

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Referen ces:

Khoo, S.C., 1988. Geology and Mineralization of the Cheroh –Tersang area, Pahang Darul

Makmur. Unpubl. Bsc. Hons. Thesis, Univ. of Malaya, 98 p.

Lee, A.K., Khong Y., and Ong, W.H., 1986. Gold Mineralization and Prospects in North

Pahang Darul Makmur, Peninsular Malaysia. Unpubl. Report for Geol. Surv. Of Malaysia,

7 – 9.

Wan Fuad Wan Hassan and Heru Sigit Purwanto, 2002. Type deposits of Primary gold

mineralization in the Central Belt of Peninsular Malaysia. Bull of the Geol. Soc. of

Malaysia, 45, 111 – 115.

Teh, G.H., 2000. Research and Industrial Applications of the Electron Probe X-ray

Microanalyzer (EPMA) in Malaysia. In: Proceedings ACXRI 2000 (Asian Conference and

X-rays and Related Technique in Research and Industry), 20 – 22 November 2000.