‘Suture zones’ in peninsular Malaysia and Thailand: implications for palaeotectonic reconstruction of southeast Asia

The existence of one or more long suture zones extending from Thailand to peninsular Malaysia has been widely accepted in almost all palaeotectonic reconstruction of southeast Asia. Geological evidence from the areas where suture zones have been proposed in these two countries are not reconcilable with many of the inferences and interpretations of the geology on which the palaeotectonic models are based. With the possible exception of the Nan-Uttaradit suture in Thailand, the relationship of the other proposed ‘suture’ to subduction processses must be regarded as highly doubtful. Correlating geological belts from north Thailand to southern peninsular Malaysia is extremely difficult, given the present limited state of our knowledge of the geology in these two geologically complex regions. Correlation, based on simple classification of granites and their implied geotectonic setting can be misleading. The timing of the proposed collision event to bring together the Gondwana terrain with the Asian terrain, as envisaged in the popular reconstruction scheme, remains one of the most crucial problem which needs to be addressed by those advocating this concept. Palaeontological, stratigraphical, igneous, metamorphic and structural evidence, which can shed light on this difficult question, give conflicting ages for the major orogenic events in this region.