The Phuket Group of peninsular Thailand

The Phuket Terrane: A Late Palaeozoic rift at the margin of Sibumasu

“…However, Ridd (1971b) was able to show that these rocks are the lateral equivalent of rocks in the Lower Peninsula which overlie Ordovician limestone and their age must therefore be Silurian or younger. Notwithstanding their erroneous age determination, the description of the Phuket Group by Mitchell et al (1970) was an important milestone in understanding the geology of the Peninsula.…”

“…As will be shown below, the presence in Lower Peninsular Thailand and the Langkawi Islands of Malaysia (both indisputably part of Sibumasu) of glacially-influenced sediments argues against Mitchell's (1992) suggestion that they were formerly separated from his Mergui Belt by an ocean. Burton (1986) proposed a revised nomenclature of the Palaeozoic rocks of western and peninsular Thailand, eschewing the term diamictite and describing the rocks as greywacke and pebbly greywacke; while accepting and widely quoting the view of Ridd (1971bRidd ( , 1980) that the 'Phuket group' was a rift-infill deposit, he was not persuaded by the arguments of Stauffer and Mantajit (1981) that deposition had been glacially-influenced. Altermann (1986) also rejected a glacial influence during deposition of these rocks and considered that they were laid down on the flank of a cratonic block which was close to or part of Palaeoeurasia, on the northern margin of Tethys, but his suggestions have found few followers.…”

Early Permian ammonoids from the Kaeng Krachan Group of the Phatthalung-Hat Yai area, southern peninsular Thailand

“…The Kaeng Krachan Group and similar lithofacies in peninsular Thailand characterized by the presence of diamictites were originally regarded as Devonian to Permian in age (Ridd, 1971;Piyasin, 1975). However, in recent studies they are generally assigned to the Carboniferous to Permian (e.g.…”

The Kanchanaburi supergroup of Peninsular and Western Thailand

“…Whilst also including mudstone and greywacke, more mature arenite is the dominant component of the Pathiu formation, possibly indicative of another source area and certainly pointing to shallowing of the basin of deposition. The Pathiu may, however, be absent, in part or in entirety due either to non-deposition and/or erosion prior to the major Permian transgression.The origin of the Phuket group is deliberated upon and, following the hypotheses of Ridd (1971a) and Asnachinda (1978), it is thought that the bulk of this rock unit was deposited in a graben formed as a continental fragment ("Shan-Thai") rifted away from Gondwanaland. Despite increasing suggestions that the Phuket is glaciogenic, in part or in whole, no unequivocal contribution from glacial sources is evident.…”

“…The origin of the Phuket group is deliberated upon and, following the hypotheses of Ridd (1971a) and Asnachinda (1978), it is thought that the bulk of this rock unit was deposited in a graben formed as a continental fragment ("Shan-Thai") rifted away from Gondwanaland. Despite increasing suggestions that the Phuket is glaciogenic, in part or in whole, no unequivocal contribution from glacial sources is evident.…”