Magmatic epidote: probable absence and implication to the geobarometry of the granitic rocks from Peninsular Malaysia

702001-100711-517-B
Author : Anuar Ismail & Azman A. Ghani
Publication : Bulletin of the Geological Society of Malaysia
Page : 231-234
Volume Number : 45
DOI : https://doi.org/10.7186/bgsm45200234

Bulletin of the Geological Society of Malaysia, Volume 45, May 2002, pp. 231 - 234

 

Magmatic epidote: probable absence and implication to the geobarometry of the granitic rocks from Peninsular Malaysia

Anuar Ismail & Azman A. Ghani

Department of Geology, University of Malaya, 50603 Kuala Lumpur

 

Abstract: Occurrence and implications of magmatic epidote in granitic rocks is reviewed. The presence of magmatic epidote in granodiorites, tonalites and trondhjemites is commonly used as evidence of magma crystallisation at pressure in the region of 6 to 8 kbar. The epidote is easily identified as they are usually euhedral, overgrowth on euhedral allanite, associated with magmatic flow, included in primary muscovite and have fine scale oscillatory zoning. The concept of magmatic epidote and its pressure is apply to granitic rocks from Peninsular Malaysia. Work on the barometry of Malaysian granitoid based on the aluminium content of amphiboles indicate that the highest crystallisation pressure of the granites is 4.98 kbar, which is below the crystallisation pressure of magmatic epidote. This may suggest that the Peninsular Malaysia granitic magmas may not have crystallised the epidote at low pressure.

https://doi.org/10.7186/bgsm45200234