Lowland river responses to intraplate tectonism and climate forcing quantified with luminescence and cosmogenic 10Be

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dc.contributor.authorJansen, JDen_AU
dc.contributor.authorNanson, GCen_AU
dc.contributor.authorCohen, TJen_AU
dc.contributor.authorFujioka, Ten_AU
dc.contributor.authorFabel, Den_AU
dc.contributor.authorLarsen, JRen_AU
dc.contributor.authorCodilean, ATen_AU
dc.contributor.authorPrice, DMen_AU
dc.contributor.authorBowman, HHen_AU
dc.contributor.authorMay, JHen_AU
dc.contributor.authorGliganic, LAen_AU
dc.date.accessioned2014-09-03T02:09:32Zen_AU
dc.date.available2014-09-03T02:09:32Zen_AU
dc.date.issued2013-03-15en_AU
dc.date.statistics2014-09-03en_AU
dc.description.abstractIntraplate tectonism has produced large-scale folding that steers regional drainage systems, such as the 1600 km-long Cooper Ck, en route to Australia's continental depocentre at Lake Eyre. We apply cosmogenic Be-10 exposure dating in bedrock, and luminescence dating in sediment, to quantify the erosional and depositional response of Cooper Ck where it incises the rising Innamincka Dome. The detachment of bedrock joint-blocks during extreme floods governs the minimum rate of incision (17.4 +/- 6.5 mm/ky) estimated using a numerical model of episodic erosion calibrated with our 10Be measurements. The last big-flood phase occurred no earlier than similar to 112-121 ka. Upstream of the Innamincka Dome long-term rates of alluvial deposition, partly reflecting synclinal-basin subsidence, are estimated from 47 luminescence dates in sediments accumulated since similar to 270 ka. Sequestration of sediment in subsiding basins such as these may account for the lack of Quaternary accumulation in Lake Eyre, and moreover suggests that notions of a single primary depocentre at base-level may poorly represent lowland, arid-zone rivers. Over the period similar to 75-55 ka Cooper Ck changed from a bedload-dominant, laterally-active meandering river to a muddy anabranching channel network up to 60 km wide. We propose that this shift in river pattern was a product of base-level rise linked with the slowly deforming syncline-anticline structure, coupled with a climate-forced reduction in discharge. The uniform valley slope along this subsiding alluvial and rising bedrock system represents an adjustment between the relative rates of deformation and the ability of greatly enhanced flows at times during the Quaternary to incise the rising anticline. Hence, tectonic and climate controls are balanced in the long term. © 2013, Elsevier Ltd.en_AU
dc.identifier.citationJansen, J. D., Nanson, G. C., Cohen, T. J., Fujioka, T., Fabel, D., Larsen, J. R., Codilean, A. T., Price, D. M., Bowman, H.H., May, J. H., & Gliganic, L. A. (2013). Lowland river responses to intraplate tectonism and climate forcing quantified with luminescence and cosmogenic 10Be. Earth and Planetary Science Letters, 366, 49-58. doi:10.1016/j.epsl.2013.02.007en_AU
dc.identifier.govdoc5501en_AU
dc.identifier.issn0012-821Xen_AU
dc.identifier.journaltitleEarth and Planetary Science Lettersen_AU
dc.identifier.pagination49-58en_AU
dc.identifier.urihttp://dx.doi.org/10.1016/j.epsl.2013.02.007en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/5839en_AU
dc.identifier.volume366en_AU
dc.language.isoenen_AU
dc.publisherElesevier Science BVen_AU
dc.subjectBerylliumen_AU
dc.subjectIsotopesen_AU
dc.subjectLuminescenceen_AU
dc.subjectSedimentsen_AU
dc.subjectDepositionen_AU
dc.subjectErosionen_AU
dc.titleLowland river responses to intraplate tectonism and climate forcing quantified with luminescence and cosmogenic 10Been_AU
dc.typeJournal Articleen_AU
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