Sistem sesar dalam Basalt Segamat: Kajian kes di Kuari Yam Fong


Author : Ibrahim Abdullah, Jatmika Setiawan & S. M. AwalnurPublication : Bulletin of the Geological Society of MalaysiaVolume : 48Page : 111-114Year : 2004


Description

Bulletin of the Geological Society of Malaysia, Volume 48, June 2004, pp. 111-114

 

Sistem sesar dalam Basalt Segamat: Kajian kes di Kuari Yam Fong

IBRAHIM ABDULLAH, JATMlKA SETIAWAN & S. M. AWALNUR

Pusat Pengajian Sains Sekitaran dan Sumber Alam, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan

 

Abstrak: Basalt Segamat diletuskan semasa Tersier Awal, ketika keadaan tektonik Semenanjung Malaysia dikatakan telah berada dalam keadaan setabil. Kajian lapangan di Kuari Yam Fong, Kampung Jabi, Segamat menunjukkan batuan, disamping telah mengalami peretakan dan pembentukan telerang kalsit, basalt di sini juga mengalami sesaran mendatar dan sesaran sungkup. Berdasarkan kepada perkaitan antara struktur yang terdapat di sini, ditafsirkan basalt Segamat telah mengalami dua kali mampatan, yang awal daripada arah timur-timurlaut (TTL) diikuti oleh mampatan dari arah timur tenggara (TTG). Telerang kalsit juga didapati tersibar dengan agak meluas dalam jalur-jalur tertentu berarah utara timurlaut dan timur- timurlaut. Sesar mendatar konjugat gererasi awal yang terhasil daripada mampatan daripada arah (TTL) dipotong dan dianjakkan oleh sistem sesar mendatar konjugat yang terhasil daripada mampatan dari TTG. Selain berkaitan dengan pembentukan sesar mendatar, sistem tegasan yang awal juga bertanggung jawab dalam pembentukan telerang kalsit. Sistem tegasan ke dua bertanggung jawab dalam pembentukan satu lagi set sesar mendatar konjugat dan sesar songsang. Hasil kajian ini juga menunjukkan bahawa sistem tegasan dalam keadaan mampatan masih beroperasi di Semenanjung Malaysia selepas zaman Tersier awal yang dikatakan telah berada dalam keadaan stabil.

 

Abstract: Segamat Basalt erupted in the Early Tertiary during which the Malay Peninsula was considered as tectonically stable. Field studies at Yam Fong Quarry, Kampung Jabi, Segamat indicate that apart from jointing and formation of veins, the basalt here has also undergone lateral and reverse faulting. Based on the relationship of the structures (faults) found here, it is interpreted that the Segamat Basalt has suffered at least two phases of compression, the earlier from east-northeast followed by east-southeast. Calcite veins are also well developed within certain zones aligned in north-northeast and east-northeast directions. The earlier set of conjugate lateral faults that formed as a result of compression from east-northeast were cut and displaced by the later conjugate lateral fault system, which resulted due to compression from east-southeast. The earlier stress system was responsible for the formation calcite veins. The later stress system was responsible for the formation of another set of conjugate lateral faults and reverse faults. The results of this study indicate that compressional stress was still present in the Malay Peninsula in the post Early-Tertiary when the area was considered as tectonically stable.

https://doi.org/10.7186/bgsm48200421