Tectonic strain recorded by magnetic fabrics (AMS) in plutons, including Mt Kinabalu, Borneo: A tool to explore past tectonic regimes and syn-magmatic deformation

Burton-Johnson, A.; Macpherson, C.G.; Muraszko, J.R.; Harrison, R.J.; Jordan, T.A.

Abstract

Tectonic strain commonly overprints magmatic fabrics in AMS (Anisotropy of Magnetic Susceptibility) data for plutonic rocks produced by both compressional and extensional regimes. Mt Kinabalu, Borneo, is a composite pluton with an exceptional vertical range of exposure and clearly defined internal contacts. We show that tectonic fabrics are recorded pervasively throughout the intrusion, even near contacts, and present a workflow distinguishing compressive and extensional syn-magmatic deformation. At Mt Kinabalu this reveals a pervasive tectonic fabric indicating NW-SE Miocene extension in Borneo at 7.9–7.3 Ma, later than previously recognised, oriented NW-SE at 319° ±13.1°. Comparing data from Mt Kinabalu with data from globally distributed studies shows that tectonic strain is commonly recorded by plutons. Therefore, AMS fabric can be used to identify the syn-magmatic tectonic setting and combined with both geochronology and evidence for paleomagnetic rotation to provide a powerful tool for accurate determination of syn-magmatic tectonic regimes and strain orientations within temporal frameworks.

Citation

Burton-Johnson, A., Macpherson, C., Muraszko, J., Harrison, R., & Jordan, T. (2019). Tectonic strain recorded by magnetic fabrics (AMS) in plutons, including Mt Kinabalu, Borneo: A tool to explore past tectonic regimes and syn-magmatic deformation. Journal of Structural Geology, 119, 50-60. https://doi.org/10.1016/j.jsg.2018.11.014

• Journal Article Type: Article
• Acceptance Date: Nov 30, 2018
• Online Publication Date: Dec 5, 2018
• Publication Date: Feb 28, 2019
• Deposit Date: Dec 6, 2018
• Publicly Available Date: Dec 5, 2019
• Journal: Journal of Structural Geology
• Print ISSN: 0191-8141
• Electronic ISSN: 1873-1201
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 119
• Pages: 50-60
• DOI: https://doi.org/10.1016/j.jsg.2018.11.014
• Public URL: https://durham-repository.worktribe.com/output/1312314