Devonian and Carboniferous stratigraphy and conodont biostratigraphy of the Malay Peninsula in a regional tectonic context

Abstract

Improved biostratigraphic dating and enhanced understanding of the stratigraphy and depositional and tectonic environments of Devonian and Carboniferous sequences in Malaysia have resolved ambiguities in previous published work and better constrain the nature and timing of the stages of tectonic evolution of the region. The Devonian and Carboniferous stratigraphy of the Malay Peninsula is discussed within a tectonic framework that includes a western Sibumasu Terrane and an eastern Sukhothai Arc (Indochina) block separated by the Bentong-Raub Suture Zone that represents the former Devonian-Triassic Palaeo-Tethys Ocean. The stratigraphy and depositional environments of the Devonian and Carboniferous of Peninsular Malaysia provide important insights into the switch from deposition in shallow shelf to deeper-water margin-slope environments on the passive margin of Gondwana during the early development of the Palaeo-Tethys Ocean. In addition, the Devonian and Carboniferous sediments and faunas of the Western Belt of the Malay Peninsula support and are consistent with placement of the Sibumasu Terrane on the Palaeozoic margin of Australian Gondwana until the early Permian (Sakmarian). Carboniferous sedimentary rocks of the Eastern Belt of the Malay Peninsula were deposited on the margin of the equatorial Indochina Block onwhich the Sukhothai Arc was constructed. Previously erected stratigraphical units, such as the 'Karak Formation', 'Bentong Group', 'Raub Group', and 'Pelong Beds' for Bentong-Raub Suture Zone complex rocks, are meaningless as stratigraphic units, and their use should be discontinued. Devonian and Carboniferous conodont biostratigraphy in the Malay Peninsula is relatively poorly known. The Lower Devonian Pterospathodus amorphognathoides Zone, Ozarkodina eosteinhornensis Zone, and Icriodus woschmidti Zone faunas are known from the Mempelam Limestone of Langkawi and Perlis, and the Upper Devonian (Frasnian) Palmatolepis linguiformis Zone faunas occur in the Sanai Limestone of Perlis. Conodont faunas of the Kanthan Limestone in Perak represent Lower-Middle Devonian (Emsian-Giventian) Eocostapolygnathus gronbergi Zone-Polygnathus asymmetricus Zone faunas, and Mississippian upper Tournaisian Scaliognathus anchoralis Zone, Visean Lochriea commutatus Zone, and Gnathodus bilineatus Zone faunas. Basal Pennsylvanian Declinognathodus noduliferus Zone faunas are also present. Significant reworking of conodonts into the Tournaisian and Visean limestones is recorded. Conodont faunas of the Panching Limestone in the eastern Belt of the Malay Peninsula represent the earliest Pennsylvanian D. noduliferus s.l.-Rhachistognathus primus Zone.