The age and paleobiogeography of brachiopod fauna discovered in pebbly mudstone at Kilim, Langkawi

Abstract

A rich brachiopod fauna was recently discovered in the pebbly mudstone overlying sandstone and limestone at Kilim, Langkawi. The fauna comprised Spirelytha buravasi (Hamada), Sulciplica thailandica (Hamada), Bandoproductus monticulus (Waterhouse), Lamniplica cf sap a (Waterhouse), Rhynchopora cf culta Waterhouse, Streptorhynchus sp., Arctitreta sp., Elasmata sp. and Trigonotreta sp. The brachiopod assemblage is very similar to that of Ko Muk in Southern Thailand. The presence of Bandoproductus monticulus (Waterhouse) suggests an Early Permian (Late Asselian to Sakmarian) age for the Kilim pebbly mudstone and its fauna. PaleobiogeographicaUy, the Kilim brachiopod fauna has a very close affinity with many other Early Permian south temperate or peri-Gondwana fauna. The faunal evidence strongly support the idea that the pebbly mudstone in the Singa Formation is of mar ine glacial diamictite.