Thermochronology

Palaeotemperature or ‘closure temperatures’ of common isotopic systems and minerals

It is widely believed that much of the SE Asian region has experienced large-scale uplift and erosion during the Cenozoic. In many places Cenozoic sedimentation is notable only by its absence, material presumed to be lost to the regions unusually deep sedimentary basins.

Thermochronology provides a method of quantifying the magnitude and timing of rock uplift and erosion experienced across the region. Thermochronology revolves around the association of isotopic dates with palaeotemperatures specific to each isotopic system and/or mineral, e.g. biotite mica Ar-Ar dating. By combining the results of analyses upon different minerals, and using different isotopic systems, it is thus possible to model the thermal history of an individual rock sample.

The SE Asia Research Group is actively involved in maintaining the rock crushing, sedimentary processing and mineral separation facilites required to go from sample to laboratory analyses. (Click here for more information on the facilities).

Collaboration:

Much of our thermochronological work is done in conjunction with collaborators from other institutions.

(U/Th)-He dating: Barry Kohn – Dept. of Earth Sciences, Melbourne University
Fission track dating: Barry Kohn – Dept. of Earth Sciences, Melbourne University
Fission Track dating: Andy Carter – Thermochronometry Research Lab., Univeristy College London/Birkbeck College
40Ar-39Ar dating: Marnie Forster – Thermochronology lab., Research School of Earth Sciences, Australian National University

Completed projects:

Granites, such as these boulders from the Malay Peninsula, provide a mineralogy ideal for thermochronology via multiple minerals

Given knowledge of a region’s geothermal gradient, the cooling history revealed by thermochronology can be related to the motion of material through the crust, drawn up to the surface by rock uplift and erosion – the process of exhumation. In turn this information can provide vital information about the rates of uplift and erosion a region has experienced, providing clues to the driving forces and processes behind it, and the magnitude and timing of erosion from a given region. We have recently started to investigate the recent exhumation of the Se Asian region, beginning with the peninsular region of Malaysia.

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.