Thailand Geology and Tectonics

Thailand presently lies in the interior of the tectonically quiet Sundaland core. It forms the stable core beneath the Thai-Malay Peninsula, southern Indochina, parts of Sumatra, Java and Borneo. It is surrounded on all sides by volcanic and seismic activity, including the subduction at the Sumatra-Java-Timor trench, and collision between Australia and eastern Indonesia.

Completed projects:

It is clear from the geometry of the sedimentary basins in Northern Thailand that their evolution is closely linked to NE-SW trending sinistral strike-slip faults and NW-SE trending dextral strike slip faults. This forms a wedge between the Mai Ping fault system in the south and the Northern Thailand Fault System in the north, consistent with north-south compression and east-west extension. In contrast the area to the south of the Mai Ping Fault, including the Gulf of Thailand seems to be much more dominated by extensional processes. Here through-going strike slip faults are rare and offsets between graben and changes in their polarity can be explained by normal linkage of extensional fault systems.

Phumee Srisuwon’s detailed analysis of the Phrae basin shows that its evolution is closely linked to sinistral movements on the NE-SW trending Phrae-Thoen fault. Anongporn Intawong will investigate the interaction between the extensional tectonics of the Gulf of Thailand and strike-slip deformation associated with the Klong Mariu Fault which marks its western boundary.

Interestingly MSc project work supported by Thai Shell suggests that small basins in the Andaman Sea may have formed at the opposite end of the Klong Mariu Fault associated with splays that would be indicative of sinistral strike-slip displacement on this fault.

While the Tertiary basins provide a record of the evolution of the area from the Late Oligocene/early Miocene, we know relatively little about the earlier Tertiary history of the area. In particular regional uplift is likely to have been an important precursor to basin formation. To investigate this Gary Nichols has embarked on a pilot programme of sample collection from granites in Northern Thailand for apatite fission track dating.

Recent Papers –

Max Webb et al., 2023. Mesozoic Magmatism of Natuna Island, Indonesia: Implications for the subduction history of eastern Indonesia. Gondwana Research

https://doi.org/10.1016/j.gr.2023.02.022

Breitfeld et al., 2022. Provenance of Oligocene-Miocene sedimentary rocks in the Cuu Long and Nam Con Son basins, Vietnam, and the early history of the Mekong River. International Journal of Earth Sciences.

https://doi.org/10.1007/s00531-022-02214-0

Nugraha et al., 2023. Plio-Pleistocene sedimentation and palaeogeographic reconstruction in the Poso Depression, Central Sulawesi, Indonesia: from a sea channel to a land bridge. Journal of Palaeogeography.

https://doi.org/10.1016/j.jop.2023.05.003

Recent News –

Amy Gough, Max Webb, and PhD Student Sam Holmes have recently returned from field seasons in SE Asia. All of them spent some time collecting river sediments on the Citarum River to look at how hydroelectric dams change heavy mineral assemblages. Max then headed off to Papua to look at how uplift of the Cyclops Mountains led to isolation of endemic species.

We’re on the move! Amy Gough has been offered a position at Heriot-Watt University as an Assistant Professor in Geoscience. Heriot-Watt has excellent ties with SE Asia, including a linked campus in Malaysia.

Amy Gough and Max Webb presented their current SEARG research at the SEAPEX Golden Jubilee in Singapore