A Neogene history of mantle convective support beneath Borneo.

Roberts, G. G. and White, N. J. and Hoggard, M. J. and Ball, P. W. and Meenan, C. (2018) A Neogene history of mantle convective support beneath Borneo. Earth and Planetary Science Letters, 496. pp. 142-158. ISSN 0012-821X DOI https://doi.org/10.1016/j.epsl.2018.05.043

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Abstract

Most, but not all, geodynamic models predict 1–2 km of mantle convective draw-down of the Earth's surface in a region centered on Borneo within southeast Asia. Nevertheless, there is geomorphic, geologic and geophysical evidence which suggests that convective uplift might have played some role in sculpting Bornean physiography. For example, a long wavelength free-air gravity anomaly of +60 mGal centered on Borneo coincides with the distribution of Neogene basaltic magmatism and with the locus of sub-plate slow shear wave velocity anomalies. Global positioning system measurements, an estimate of elastic thickness, and crustal isostatic considerations suggest that regional shortening does not entirely account for kilometer-scale regional elevation. Here, we explore the possible evolution of the Bornean landscape by extracting and modeling an inventory of 90 longitudinal river profiles. Misfit between observed and calculated river profiles is minimized by smoothly varying uplift rate as a function of space and time. Erosional parameters are chosen by assuming that regional uplift post-dates Eocene deposition of marine carbonate rocks. The robustness of this calibration is tested against independent geologic observations such as thermochronometric measurements, offshore sedimentary flux calculations, and the history of volcanism. A calculated cumulative uplift history suggests that kilometer-scale Bornean topography grew rapidly during Neogene times. This suggestion is corroborated by an offshore Miocene transition from carbonate to clastic deposition. Co-location of regional uplift and slow shear wave velocity anomalies immediately beneath the lithospheric plate implies that regional uplift could have been at least partly generated and maintained by temperature anomalies within an asthenospheric channel.

Item Type:	Article
Uncontrolled Keywords:	2018AREP; IA74
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 06 - Part-III Projects 08 - Green Open Access 12 - PhD
Journal or Publication Title:	Earth and Planetary Science Letters
Volume:	496
Page Range:	pp. 142-158
Identification Number:	https://doi.org/10.1016/j.epsl.2018.05.043
Depositing User:	Sarah Humbert
Date Deposited:	01 Jun 2018 10:54
Last Modified:	11 Apr 2019 11:31
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4289

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