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Sains Malaysiana 54(1)(2025): 77-92 http://doi.org/10.17576/jsm-2025-5401-07
Geokimia Pegmatit di Gunung Jerai dan Bukit Mor, Semenanjung Malaysia: Implikasi terhadap Pengelasan Pegmatit dan Potensi Pemineralan
(Geochemistry of
Pegmatites in Gunung Jerai and Bukit Mor, Peninsular Malaysia: Implications for
Pegmatite Classification and Mineralization Potential)
NUR SYAHIRAH ALIAS1,*,
MOHD BASRIL ISWADI BASORI1 & NASIRUDIN YUSOFF2
1Jabatan Sains Bumi dan Alam Sekitar, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia,
43600 UKM Bangi, Selangor, Malaysia
Received: 16 May 2024/Accepted:
11 September 2024
Abstrak
Pegmatit di sekitar Gunung Jerai, Kedah dan Bukit Mor,
Johor, Semenanjung Malaysia merupakan dua kawasan utama yang telah diteroka dan dilombong bagi mendapatkan timah (Sn). Namun, kajian pengelasan pegmatit dan potensi sumber logam nadir dalam pegmatit di Semenanjung Malaysia masih terhad dan belum pernah diterbitkan. Penyelidikan ini mengkaji pengelasan pegmatit dan potensi pemineralan logam nadir di dalam pegmatit Jerai dan Bukit Mor berdasarkan pencirian geokimia. Analisis geokimia menggunakan peralatan Spektrometri Pancaran Plasma Gandingan Aruhan (ICP-ES) dan Spektrometri Jisim Plasma Gandingan Aruhan (ICP-MS) dijalankan untuk menentukan kandungan unsur major, surih dan nadir bumi (REE) di dalam pegmatit. Hasil analisis geokimia menunjukkan kandungan yang tinggi bagi SiO2, Al2O3 dan K2O+Na2O di dalam pegmatit di kedua-dua kawasan kajian dengan memperlihatkan komposisi granit iaitu berasal daripada protolit granit. Nilai indeks ketepuan aluminium (ASI) mengelaskan jenis magma yang membentuk pegmatit sebagai peralumina, manakala plot SiO2 melawan CaO+Na2O+K2O menunjukkan asalan magma bagi pembentukan pegmatit adalah granitoid jenis-S yang mengalami tahap fraksinasi tinggi. Seterusnya, pegmatit Jerai dan Bukit Mor boleh dikelaskan sebagai kumpulan LCT kerana dicirikan oleh kepekatan rendah Ca, Mg, Fe, Sr, Ba dan REE. Bagi potensi pemineralan, pegmatit Jerai dan Bukit Mor menunjukkan pengayaan bagi unsur logam nadir Rb, Li, Cs, Ga, Ta dan Sn dengan kelimpahan REE yang rendah hingga sederhana.
Kata kunci: Bukit Mor; geokimia; Gunung Jerai; pegmatit; pemineralan
Abstract
Pegmatites in Gunung Jerai, Kedah and Bukit Mor,
Johor, Peninsular Malaysia are the two main areas that have been explored and
mined for tin (Sn). However, studies of pegmatite classification and potential
sources of rare metals in pegmatites of Peninsular Malaysia are still very
limited and have never been published. This study investigates the
classification of pegmatite and its implications for rare metal mineralization
in the Jerai and Bukit Mor pegmatites based on geochemical characterization. Geochemical analysis using
Inductively Coupled Plasma-Emission Spectroscopy (ICP-ES) and Inductively
Coupled Plasma-Mass Spectrometry (ICP-MS) were conducted to determine major,
trace, and REE contents in pegmatites. The geochemical results show high SiO2,
Al2O3 and K2O+Na2O in pegmatite for
both study areas, indicating a granite composition derived from granitic
protoliths. The aluminium saturation index (ASI) classified the pegmatites as
peraluminous, whereas the plot of SiO2 versus CaO+Na2O+K2O
indicates the origin of the magma for the formation of the pegmatite is S-type
granitoid that have experienced significant fractionation. Moreover, the Jerai and Bukit Mor pegmatites
can be classified as LCT group pegmatites because they are characterized by low
levels of Ca, Mg, Fe, Sr, Ba dan REE contents. In term of mineralization
potential, the Jerai and Bukit Mor pegmatites are enriched with rare metal elements such as Rb,
Li, Cs, Ga, Ta, and Sn, and exhibit low to moderate levels of REE.
Keywords: Bukit Mor;
geochemistry; Gunung Jerai;
pegmatite; mineralization
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