Sains Malaysiana 36(2): 117-122 (2007) 

Taburan  Pb, Cr Dan Cu Di Dalam Bijih Besi Primer dan

Sekunder Di Ladang Toh Pawang, Kedah

(The Distribution of Pb, Cr and Cu in the Primary and Secondary

Iron Ore in Ladang Toh Pawang, Kedah)

Habibah Hj. Jamil, Wan Fuad Wan Hassan & Mohamad Md Tan

Program Geologi, Pusat Sains Sekitaran dan Sumber Alam

Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor, Malaysia

Diserahkan: 3 September 2006 / Diterima: 23 April 2007

ABSTRAK

Terdapat dua jenis permineralan bijih besi di kawasan Ladang Toh Pawang, Kedah iaitu bijih besi primer dan sekunder.  Kepekatan Pb dan Cr yang amat rendah ditemui dalam bijih besi primer (bdl) manakala Cu ditemui sebagai bendasing (60-93 μg/g).  Kepekatan Cr dan Cu meningkat di persentuhan antara jasad rejahan bijih besi dengan batuan sekitar.  Kepekatannya masing-masing ialah sebanyak 27-30 μg/g and 242-294 μg/g.   Pengayaan logam-logam tersebut disebabkan oleh penggantian metasomatik apabila magma likat yang panas berinteraksi dengan batuan syal Formasi Mahang yang kaya besi.  Secara umum, kepekatan Pb dan Cr dalam bijih besi sekunder lebih tinggi berbanding dengan pemineralan bijih besi primer yang mana masing-masing berjulat 3-7 μg/g and 121-151 μg/g.  Kepekatan Cu di dalam bijih besi primer dan sekunder hampir sama.  Taburan Pb, Cr dan Cu di dalam bijih besi sekunder berpunca daripada luluhawa batuan syal Formasi Mahang yang kaya besi.  Ketika proses permukaan berlaku, logam-logam berat tersebut telah dijerap daripada air bawah tanah lalu turut terenap bersama-sama dengan bijih besi sekunder.      

Kata kunci: Bijih besi; Pb; Cr; Cu

ABSTRACT

There are two types of iron ore mineralization in Ladang Toh Pawang area, Kedah  i.e. the  primary and secondary ore. Very low concentrations of Pb and Cr are found in the primary ore (bdl) whereas Cu is found as impurity (60-93 μg/g).  The concentrations of Cr and Cu increased at the contact between the intruding  iron ore  body  and the country rocks.  Their concentrations are 27-30 μg/g and 242-294 μg/g respectively.  Enrichment of these metals is caused by the metasomatic replacement  when the hot molten magma interacted with the ferrugeneous shales of Mahang Formation. Generally, the concentrations of Pb and Cr in the secondary iron ore are higher compared to the primary iron ore mineralization which ranges 3-7 μg/g and 121-151 μg/g respectively.  The concentrations of Cu in primary and secondary iron ore are quite similar.  Distribution of Pb, Cr and Cu in the secondary iron ore originated from the weathered ferrugeneous shales of Mahang Formation.  During surface processes, these metals were scavenged from ground waters and thus co-precipitated with the secondary iron ores.

Keywords: Iron ore; Pb; Cr; Cu  

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