Quantitative resolution of the debate over antiquity of the central Australian landscape: implications for the tectonic and geomorphic stability of cratonic interiors

Belton, David; Brown, R. W.; Kohn, Barry P.; Fink, David; Farley, K. A.

doi:10.1016/s0012-821x(03)00705-2

Cited by 99 publications

(64 citation statements)

References 40 publications

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“…Erosion in the MDV is not likely to be completely steady through time and is probably punctuated by episodes of relatively rapid erosion due to slope failures or high-wind events. The erosion rates reported in this study are slow and are comparable to the lowest rock erosion rates reported, which also come from arid regions Summerfield et al, 1999;Belton et al, 2004;Dunai et al, 2005]. Under these slow erosion rates, the effective halflives of the nuclides are quite large, which means that the measured nuclide concentrations integrate erosion over a very long period of time, on the order of 10 5 -10 6 years.…”

Section: Erosion Rates Of Regolith In the MDVsupporting

confidence: 73%

Quantifying regolith erosion rates with cosmogenic nuclides ¹⁰Be and ²⁶Al in the McMurdo Dry Valleys, Antarctica

Morgan¹,

Putkonen²,

Balco³

et al. 2010

J. Geophys. Res.

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[1] The McMurdo Dry Valleys, Antarctica (MDV) are among the oldest landscapes on Earth, and some landforms there present an intriguing apparent contradiction such that millions of years old surface deposits maintain their meter-scale morphology despite the fact that measured erosion rates are 0.1-4 m Ma −1 . We analyzed the concentration of cosmic ray-produced 10 Be and 26 Al in quartz sands from regolith directly above and below two well-documented ash deposits in the MDV, the Arena Valley ash ( 40 Ar/ 39 Ar age of 4.33 Ma) and the Hart ash (K-Ar age of 3.9 Ma). Measured concentrations of 10 Be and 26 Al are significantly less than expected given the age of the in situ air fall ashes and are best interpreted as reflecting the degradation rate of the overlying sediments. The erosion rate of the material above the Arena Valley ash that best explains the observed isotope profiles is 3.5 ± 0.41 × 10 −5 g cm) for the past ∼4 Ma. For the Hart ash, the erosion rate is 4.8 ± 0.21 × 10 −4 g cm −2 yr −1 (∼2.6 m Ma) for the past ∼1 Ma. The concentration profiles do not show signs of mixing, creep, or deflation caused by sublimation of ground ice. These results indicate that the slow, steady lowering of the surface without vertical mixing may allow landforms to maintain their meter-scale morphology even though they are actively eroding.

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Section: Erosion Rates Of Regolith In the MDVsupporting

confidence: 73%

Quantifying regolith erosion rates with cosmogenic nuclides ¹⁰Be and ²⁶Al in the McMurdo Dry Valleys, Antarctica

Morgan¹,

Putkonen²,

Balco³

et al. 2010

J. Geophys. Res.

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“…A more recent and sharply contrasting view, grounded firmly in apatite fission track (AFT) thermochronology (Osadetz et al, 2002;Belton et al, 2004;Kohn et al, 2009), is that even shield interiors are tectoni cally dynamic, with km-scale phases of burial and exhumation that require large vertical movements of deep-rooted continental crust and long periods of erosion during the Phanerozoic. Resolving this debate is important not only for assessing the stability of shields but also for reconstructing erosion histories on shields and quantifying sediment supply to intra-cratonic and marginal basins.…”

Section: Introductionmentioning

confidence: 99%

Phanerozoic denudation across the Kola Peninsula, Northwest Russia: implications for long-term stability of Precambrian shield margins

Hall¹

2015

NJG

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Contrasting views exist on the stability of the Earth's shield regions over the last 1 Ga that have major implications for reconstructing erosion patterns on shields and the supply of sediment to intra-cratonic and marginal basins. This paper explores Phanerozoic denudation rates and patterns on the northern part of the Fennoscandian Shield in the Kola Peninsula, Northwest Russia. This shield region was intruded by magmatic rocks of the Kola Alkaline Province (KAP) in the Devonian and Early Carboniferous. The KAP comprises a varied suite of alkali-ultramafic plutonic and hypabyssal intrusions, diatremes and dykes that was emplaced at various depths in the crust and allows assessment of depths and rates of erosion during and since the KAP magmatic episode. Further evidence of long-term denudation is provided by Mesoproterozoic and Neoproterozoic cover rocks found around the margins of the Kola Peninsula and in the White Sea. The burial and exhumation history is compared to available Apatite Fission Track (AFT) data for the Kola Peninsula and adjacent areas. Post-Devonian denudation rates on the shield rocks of the Kola Peninsula have varied in space and time. Around the periphery of the Kola Peninsula, low long-term denudation of shield rocks is indicated by the survival of Riphean cover rocks and Late Devonian lavas, kimberlite crater facies and near-surface emplacement of dykes. In contrast, in the main belts of KAP intrusions, 4-6 km of rock was removed in response to doming between 460 and 360 Ma. Deep denudation is indicated by the emplacement depths of alkaline intrusions and Phoscorite-Carbonatite pipes (PCPs). Erosion on the Kola Peninsula since 360 Ma has been far more limited. Extensive, shallow, late-stage magmatism associated with PCPs, dykes and the large alkaline intrusions in the KAP indicates that erosion depths nowhere exceeded 2 km. PostDevonian denudation has removed <1 km of rock from the margins of the Kola Peninsula and from the backslope of the Saariselkä-Karelia scarp in northern Finland. AFT data point to an important phase of erosion in the early Mesozoic but depths of unroofing of 3-5 km based on AFT cooling ages for this later phase are in conflict with the evidence of lesser erosion provided by the late-stage KAP intrusions and also require unrealistic depths of former Devonian to Triassic cover rocks. Mean denudation rates were greatest (up to 40 m/Myr) during the KAP magmatic phase. Post-Devonian rates across the Kola Peninsula and adjacent shield areas were much lower (<3-6 m/Myr) and are compatible with low long-term denudation rates for other cratons. Further resolution of long-term denudation patterns and rates on the Kola Peninsula requires the application of low-temperature thermochronometry, detailed examination of the regional geomorphology and firmer dating of ancient weathering episodes.

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“…They concluded that the Cambrian terraces and Ashburton Surface represented the oldest-known persisting landforms in the world, and attributed their survival to 'marked tectonic stability' in the region. In contrast, in a more recent study, Belton et al (2004) have concluded, from apatite fission track data, that the region underwent kilometre-scale burial and exhumation prior to and during the Mesozoic, and that the Cambrian terraces are exhumed features. Belton et al (2004) also calculated long-term (10 6 -year timescale) erosion rates, based on cosmogenic nuclides, of $0.3 m Ma À1 for the quartzites of the Ashburton Surface, and 2-4 m Ma À1 for the valley-fill terraces, and concluded that this order of magnitude difference in erosion rates between the ridge tops and the Cambrian terraces is consistent with exhumation of a palaeovalley-fill.…”

Section: Tennant Creek/davenport Provincementioning

confidence: 82%

“…Pillans, 1997;Heimsath et al, 2000) and bedrock erosion (e.g. Bierman and Caffee, 2002;Belton et al, 2004) in Australia may indeed be low by world standards, they are not low enough to explain the continuous subaerial survival of pre-Cenozoic landforms and weathering profiles. For example, erosion rates, calculated from cosmogenic isotope measurements for bare rock surfaces in Australia, vary with lithology, topography and rainfall.…”

Section: Reconciling the Survival Of Ancient Regolith And Landforms Imentioning

confidence: 96%

Pre‐Quaternary landscape inheritance in Australia

Pillans

2007

J Quaternary Science

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Palaeogeographic reconstructions indicate that parts of the Australian continent have been subaerially exposed for hundreds of millions of years. Some landforms and regolith are demonstrated to be at least 300 million years old, but their persistence at or near the surface is inconsistent with long-term denudation rate estimates based on cosmogenic nuclides and apatite fission track thermochronology. Burial and exhumation are suggested as significant preservation factors, in conjunction with prolonged tectonic stability and a shift to more arid climatic regimes in the Cenozoic.

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Quantitative resolution of the debate over antiquity of the central Australian landscape: implications for the tectonic and geomorphic stability of cratonic interiors

Cited by 99 publications

References 40 publications

Quantifying regolith erosion rates with cosmogenic nuclides ¹⁰Be and ²⁶Al in the McMurdo Dry Valleys, Antarctica

Quantifying regolith erosion rates with cosmogenic nuclides ¹⁰Be and ²⁶Al in the McMurdo Dry Valleys, Antarctica

Phanerozoic denudation across the Kola Peninsula, Northwest Russia: implications for long-term stability of Precambrian shield margins

Pre‐Quaternary landscape inheritance in Australia

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Quantitative resolution of the debate over antiquity of the central Australian landscape: implications for the tectonic and geomorphic stability of cratonic interiors

Cited by 99 publications

References 40 publications

Quantifying regolith erosion rates with cosmogenic nuclides 10Be and 26Al in the McMurdo Dry Valleys, Antarctica

Quantifying regolith erosion rates with cosmogenic nuclides 10Be and 26Al in the McMurdo Dry Valleys, Antarctica

Phanerozoic denudation across the Kola Peninsula, Northwest Russia: implications for long-term stability of Precambrian shield margins

Pre‐Quaternary landscape inheritance in Australia

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Quantifying regolith erosion rates with cosmogenic nuclides ¹⁰Be and ²⁶Al in the McMurdo Dry Valleys, Antarctica

Quantifying regolith erosion rates with cosmogenic nuclides ¹⁰Be and ²⁶Al in the McMurdo Dry Valleys, Antarctica