Thermochronology, Mount Kinabalu

Dynamic thermochronological study of Mt Kinabalu, Sabah, Malaysia

Christian Sperber, completed PhD

This project intends to apply cutting-edge low-temperature thermochronological techniques to resolve the tectonic and structural evolution of Mt Kinabalu, the highest mountain in Southeast Asia. This enigmatic peak stands out dramatically from the regional topography, with its 4100m summit rising above a massif largely below 1000m high, and with few other peaks up to 2500m. The full relief of Mt Kinabalu is even greater, as immediately to the north the topography descends rapidly to depths of more than 2000 m in the Sulu Sea. A related project examined the crystallisation and higher-temperature thermal history of the mountain’s granitic litholiges.

The mountain is composed of granite, and although the exact age of intrusion is uncertain, it is estimated to behave been emplaced and exhumed in a total of less than 15 Ma. A similar granite body along strike in Palawan has yielded U-Pb ages of ~15 Ma, and available K-Ar ages from rocks and minerals from the Kinabalu pluton itself and nearby minor intrusions spread over a range of about 8 million years. Existing data indicate that Mt Kinabalu must have experienced dramatic recent uplift and exhumation, but the timing and mechanism of this remain ambiguous. Pilot fission track dating studies estimate removal of 4-8 km of crust in less than 5 Ma.

High resolution DEM of Mount Kinabalu,Sabah

Summit of Mount Kinabalu, Sabah

View of Mount Kinabalu, Sabah

Not only is this rapid unroofing unusual, its dynamic cause is also unclear. Immediately to the north and south of Kinabalu are large sedimentary basins that appear to have been subsiding at the same time the Kinabalu granite was forming. Recent and ongoing studies in Sabah by the SE Asia Research Group at Royal Holloway suggest a number of tectonic hypotheses that could account for the apparent subsidence and uplift. This project utilises low-temperature thermochronology – specifically apatite (U-Th)/He and apatite & zircon fission track dating – to test these hypotheses.

Collaborators
(U-Th)/He and fission track analyses were undertaken in collaboration with Barry Kohn & Asaf Raza (University of Melbourne), with additional fission track analyses carried aided by Andy Carter (University College London)

Recent Papers –

Max Webb et al., 2020. Isotopic mapping reveals the location of crustal fragments along a long-lived convergent plate boundary. Lithos.

https://doi.org/10.1016/j.lithos.2020.105687

Max Webb et al., 2020. The history of Cenozoic magmatism and collision in NW New Guinea – New insights into the tectonic evolution of the northernmost margin of the Australian Plate. Gondwana Research.

https://doi.org/10.1016/j.gr.2019.12.010

Amy Gough et al., 2020. Mid-Cenozoic fluvio-deltaic to marine environments of the Salin Sub-basin, Central Myanmar. Journal of Asian Earth Sciences.

https://doi.org/10.1016/j.jseaes.2019.104143

Recent News –

Amy Gough and Max Webb attended the Restech 2.0 Virtual Reservoir Conference. Amy Gough presented new SEARG research on the pitfalls of light mineral studies for sedimentary provenance in tropical climates.

Amy Gough was awarded an honorary research fellowship of the British Geological Survey and continues to foster collaborative relationships between SEARG and the BGS.