Intrabed andalusite abundance variation as an indicator of graded beds: an example from Kuala Kemasik, Trengganu


Author : K.R. Chakraborty and I. MetcalfePublication : Bulletin of the Geological Society of MalaysiaVolume : 16Page : 159 – 166Year : 1983


Description

Bulletin of the Geological Society of Malaysia, Volume 16, Dec. 1983, pp. 159 – 166

 

Intrabed andalusite abundance variation as an indicator of graded beds: an example from Kuala Kemasik, Trengganu

K.R. CHAKRABORTY and I. METCALFE

Department of Geology University of Malaya Kuala Lumpur, Malaysia

 

Abstract: Interbedded meta-argillites and meta-arenites exposed at Kuala Kemasik, Trengganu, show abundant but selective development of andalusite. Many individual beds show a characteristic distribution pattern of andalusite from rare at the base to abundant at the top. This distribution pattern is interpreted to be the result of preferential development of andalusite in the clay rich part of premetamorphic normal sedimentary graded beds. The development of andalusite porphyroblasts in the original finer part of the beds has given rise to a partial reversal of size gradation. The inferred graded beds indicate that the metasediments are right side up which is consistent with the observed small scale current bedding and load structures.