Rijang Beradiolaria Semenanjung Malaysia: Kewujudan, Usia dan Sekitaran Pengendapan (Radiolarian Chert of Peninsular Malaysia: Occurrence, Age and Sedimentation Environment)

Chemical compositions, and radiolarian content of several Late Paleozoic and Mesozoic chert samples have been studied. The occurrence of radiolaria in the chert permits dating of the rock more accurate. The age of the Kubang Pasu chert is Early Carboniferous. The age of the Kodiang chert is Carnian­Norian, Late Triassic. The age of the Semanggol chert ranges from Late Permian to Middle Triassic. The cherts from Ulu Kelantan and Jengka area I are dated as Early Permian and late Permian respectively. Three lithologic I associations are recognised; 1) chert-limestone association represents a subsidence association which is found at the Kodiang Formation, 2) chertclastic association represents continental margin chert association which is very common in Peninsular Malaysia. It is found in the Semanggol Formation, Kubang Pasu Formation, and the chert from Ulu Kelantan, and 3) chertpyroclastic association which represents island-arc association is found in the chert at the Jengka area, Pahang.
Beberapa contoh rijang berusia Paleozoic Akhir dan Mesozoik telah dikaji kandungan kimia, dan radiolaria. Kewujudan radiolaria dalam bantuan rijang telah membolehkan penentuan usia yang lebih jitu terhadap lapisan rijang di beberapa formasi batuan di Semenanjung Malaysia. Rijang Formasi Kubang Pasu berusia Karbon Awal. Rijang Formasi Kodiang berusia Karnian Norian, Trias Akhir. Rijang Formasi Semanggol berusia Perm Akhir hingga Trias Tengah. Rijang di kawasan Ulu Kelantan berusia Perm Bawah. Rijang di kawasan Jengka, Pahang berusia Perm Akhir. Tiga sekutuan batuan rijang telah dikenalpasti; 1) sekutuan rijang-batu kapur atau dikenali sebagai sekutuan ambelesan yang didapati di Formasi Kodiang, 2) sekutuan rijang­batuan klastik atau dikenali sebagai sekutuan rijang pinggir benua, sekutuan ini banyak ditemui di Semenanjung Malaysia terutama dalam Formasi Semanggol, Formasi Kubang Pasu dan rijang di Ulu Kelantan dan 3) sekutuan rijang-piroklastik atau dikenali sebagai sekutuan arka-kepulauan didapati pada batuan rijang di kawasan Jengka, Pahang.