Geomorphic imprint of dynamic topography and intraplate tectonism in central Australia

Simple item page
dc.contributor.authorJansen, JDen_AU
dc.contributor.authorSandiford, Men_AU
dc.contributor.authorFujioka, Ten_AU
dc.contributor.authorCohen, TJen_AU
dc.contributor.authorStruck, Men_AU
dc.contributor.authorAnderson, SPen_AU
dc.contributor.authorAnderson, RSen_AU
dc.contributor.authorEgholm, DLen_AU
dc.date.accessioned2024-05-08T23:02:58Zen_AU
dc.date.available2024-05-08T23:02:58Zen_AU
dc.date.issued2020-05-04en_AU
dc.date.statistics2023-05-08en_AU
dc.description.abstractThe mantle convection accompanying plate motion causes vertical movements of up to a few hundred metres at Earth’s surface over wavelengths of 102–103 km. This dynamic topography appears to come and go at ~ 1–10 Myr timescales in areas that are often well away from plate margins, although its spatial and temporal characteristics are subject to ongoing debate. Since such motions are small and transient, discriminating convective signals from other drivers of relief generation and/or sediment dispersal remains tricky. An outstanding challenge is to detect these elusive, transient undulations from a tell-tale geomorphic imprint preserved in either drainage patterns or the stratigraphic record. In the intra-plate setting of central Australia, a 30 km long sinuous gorge is developed where the major regional drainage, Finke River, dissects a band of low hills. Remarkably, this gorge is intertwined with an abandoned and less deeply incised gorge that forms hanging junctions and shares similar width and sinuosity. This unusual overprinting of the two gorges remains unexplained. With an aim to investigate the history of the intertwined gorges, we measured cosmogenic 10Be and 26Al in fluvial gravels stored in the palaeovalley cutoffs. The gravels are remnants of major alluviation episodes that we surmise result from ongoing vertical motions associated with dynamic topography. We use a Markov chain Monte Carlo-based inversion model to test two hypotheses to explain the nuclide inventory contained within the stored fluvial gravels. In the first case, rapid alluviation and erosion since 1 Ma preserves the nuclide memory of the source area; in the second, the nuclide memory is erased during long-term fluvial storage (> 5 Myr) and is restored during exhumation of the palaeovalley gravel-pile. The two hypotheses are therefore limiting-case scenarios that constrain overall fast versus slow landscape evolution, respectively. Our model results suggest that long-term burial decouples the source-area signal from nuclide abundances measured in the palaeovalley gravels. This casts events into a Miocene timescale. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 Licence.en_AU
dc.identifier.citationJansen, J., Sandiford, M., Fujioka, T., Cohen, T., Struck, M., Anderson, S., Anderson, R., & Egholm, D. (2020). Geomorphic imprint of dynamic topography and intraplate tectonism in central Australia. Presentation to the EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20791. Retrieved from: https://doi.org/10.5194/egusphere-egu2020-20252en_AU
dc.identifier.conferenceenddate2020-05-08en_AU
dc.identifier.conferencenameEGU General Assembly 2020en_AU
dc.identifier.conferenceplaceOnlineen_AU
dc.identifier.conferencestartdate2020-05-04en_AU
dc.identifier.otherEGU2020-20252en_AU
dc.identifier.urihttps://doi.org/10.5194/egusphere-egu2020-20252en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15593en_AU
dc.language.isoenen_AU
dc.publisherCopernicus GmbHen_AU
dc.relation.urihttps://doi.org/10.5194/egusphere-egu2020-20252en_AU
dc.subjectTectonicsen_AU
dc.subjectPlate tectonicsen_AU
dc.subjectAustraliaen_AU
dc.subjectEarth crusten_AU
dc.subjectEarth planeten_AU
dc.subjectGeomorphologyen_AU
dc.subjectBeryllium 10en_AU
dc.subjectAluminium 26en_AU
dc.subjectSedimentsen_AU
dc.subjectMonte Carlo Methoden_AU
dc.titleGeomorphic imprint of dynamic topography and intraplate tectonism in central Australiaen_AU
dc.typeConference Abstracten_AU
Files
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.63 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Conference Publications