Spatial and Temporal Pattern of Australian Dynamic Topography from River Profile Modeling

Czarnota, K. and Roberts, G. G. and White, N. J. and Fishwick, S. (2014) Spatial and Temporal Pattern of Australian Dynamic Topography from River Profile Modeling. Journal of Geophysical Research-Solid Earth. ISSN 0148-0227 DOI https://doi.org/10.1029/2013JB010436

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Abstract

Despite its importance, the temporal and spatial evolution of continental dynamic topography is poorly known. Australia's isolation from active plate boundaries and its rapid northward motion within a hot spot reference frame make it a useful place to investigate the interplay between mantle convection, topography, and drainage. Offshore, dynamic topography is relatively well constrained and can be accounted for by Australia's translation over the mantle's convective circulation. To build a database of onshore constraints, we have analyzed an inventory of longitudinal river profiles, which is sensitive to uplift rate history. Using independently constrained erosional parameters, we determine uplift rates by minimizing the misfit between observed and calculated river profiles. Resultant fits are excellent and calculated uplift histories match independent geologic constraints. We infer that western and central Australia underwent regional uplift during the last 50 Myr and that the Eastern Highlands have been uplifted in two stages. The first stage from 120 to 80 Ma, coincided with rifting along the eastern margin and its existence is supported by thermochronological measurements. A second stage occurred at 80–10 Ma, formed the Great Escarpment, and coincided with Cenozoic volcanism. The relationship between topography, gravity anomalies, and shear wave tomographic models suggest that regional elevation is supported by temperature anomalies within the lithosphere's thermal boundary layer. Morphology and stratigraphy of the Eastern Highlands imply that these anomalies have been coupled to the base of the plate during Australia's northward motion over the last 70 Myr.

Item Type:	Article
Additional Information:	©2014. American Geophysical Union. All Rights Reserved.
Uncontrolled Keywords:	2013AREP; IA66; PhD.,
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access
Journal or Publication Title:	Journal of Geophysical Research-Solid Earth
Identification Number:	https://doi.org/10.1029/2013JB010436
Depositing User:	Sarah Humbert
Date Deposited:	16 Dec 2013 12:44
Last Modified:	31 Oct 2014 01:00
URI:	http://eprints.esc.cam.ac.uk/id/eprint/2933

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