Production rate of cosmogenic 21Ne in quartz estimated from 10Be, 26Al, and 21Ne concentrations in slowly eroding Antarctic bedrock surfaces

Balco, Greg; Shuster, David L.

doi:10.1016/j.epsl.2009.02.006

Cited by 84 publications

(105 citation statements)

References 34 publications

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“…Changes in the degradation rate that are on much shorter timescales than the effective half-life will cause only small variations in the nuclide concentrations relative to the longterm erosional equilibrium concentration value (Balco and Shuster, 2009). This means that if the effective half-life is on the order of 10 5 to 10 6 years, then even changes in the erosion rate on the order of 10 4 years will not signifi cantly affect the measured nuclide concentration.…”

Section: Error Analysismentioning

confidence: 99%

Degradation of glacial deposits quantified with cosmogenic nuclides, Quartermain Mountains, Antarctica

Morgan

Putkonen

Balco

et al. 2011

Earth Surf Processes Landf

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Many glacial deposits in the Quartermain Mountains, Antarctica present two apparent contradictions regarding the degradation of unconsolidated deposits. The glacial deposits are up to millions of years old, yet they have maintained their meterscale morphology despite the fact that bedrock and regolith erosion rates in the Quartermain Mountains have been measured at 0·1-4·0 m Ma . Additionally, ground ice persists in some Miocene-aged soils in the Quartermain Mountains even though modeled and measured sublimation rates of ice in Antarctic soils suggest that without any recharge mechanisms ground ice should sublimate in the upper few meters of soil on the order of 10 3 to 10 5 years. This paper presents results from using the concentration of cosmogenic nuclides beryllium-10 ( 10 Be) and aluminum-26 ( 26 Al) in bulk sediment samples from depth profi les of three glacial deposits in the Quartermain Mountains. The measured nuclide concentrations are lower than expected for the known ages of the deposits, erosion alone does not always explain these concentrations, and defl ation of the tills by the sublimation of ice coupled with erosion of the overlying till can explain some of the nuclide concentration profi les. The degradation rates that best match the data range 0·7-12 m Ma −1 for sublimation of ice with initial debris concentrations ranging 12-45% and erosion of the overlying till at rates of 0·4-1·2 m Ma −1. Overturning of the tills by cryoturbation, vertical mixing, or soil creep is not indicated by the cosmogenic nuclide profi les, and degradation appears to be limited to within a few centimeters of the surface. Erosion of these tills without vertical mixing may partially explain how some glacial deposits in the Quartermain Mountains maintain their morphology and contain ground ice close to the surface for millions of years.

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Section: Error Analysismentioning

confidence: 99%

Degradation of glacial deposits quantified with cosmogenic nuclides, Quartermain Mountains, Antarctica

Morgan

Putkonen

Balco

et al. 2011

Earth Surf Processes Landf

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“…In the Supplementary File, Table S3 shows the major element chemistry of the feldspar separates. We then extracted 21 Ne in several heating steps as described in Balco and Shuster (2009); Tables S2 and S4 show results.…”

Section: Sample Preparation For Cosmogenic 21 Ne Analysesmentioning

confidence: 99%

“…Neon was separated from other gases on a temperature-controlled cryogenic trap held at 70 K. The purified Ne was analyzed using the MAP-215 mass spectrometer in the BGC Noble Gas Thermochronometry Lab. Interferences on 22 Ne from CO þþ 2 and 20 Ne from Ar ++ were corrected for by analyzing a spike of 39 Ar during the analysis of Ne (for full details see Balco and Shuster, 2009), although these corrections were negligible in the diffusion experiments. Total amounts of 21 Ne were quantified by peak height comparison to a manometrically-calibrated air standard; the air standard yielded Ne isotopic composition indistinguishable from atmospheric.…”

Section: Experimental Protocolmentioning

confidence: 99%

“…Several studies have quantified 21 Ne production rates in quartz (Niedermann, 2002;Balco and Shuster, 2009;Amidon et al, 2009;Goethals et al, 2009;Kober et al, 2011), and quantitative retention of 21 Ne in quartz at Earth surface temperatures has been clearly established by both laboratory diffusion experiments and observations of natural samples (Niedermann et al, 1994;Kober et al, 2005;Shuster and Farley, 2005). It is probably safe to assume that minerals that tightly retain He (e.g., olivine and pyroxene; Trull et al, 1991;Trull and Kurz, 1993; retain neon, although we are not aware of quantitative measurements of diffusion kinetics in these minerals or in others that are potentially useful for exposure dating (e.g., feldspars).…”

Section: Introductionmentioning

confidence: 99%

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Neon diffusion kinetics in olivine, pyroxene and feldspar: Retentivity of cosmogenic and nucleogenic neon

Gourbet

Shuster

Balco

et al. 2012

Geochimica et Cosmochimica Acta

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“…Developments in the potential to calculate exposure ages and erosion rates, e.g. Balco and Shuster (2009) have rejuvenated interest in rates of surface lowering, e.g. Wilson et al (2012).…”

Section: Introductionmentioning

confidence: 99%

Measurement of rates of surface lowering of limestone in the southern Pennines: an example in the Wye catchment, Derbyshire, UK

Banks

Jones

2014

Proceedings of the Geologists' Association

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Measurement of the differential denudation between chert and limestone in a Carboniferous limestone sequence that was cut during excavations for a railway tunnel (in 1865) has provided a means of assessing limestone dissolution rates in a valley side setting in the southern Pennines over the last ~150 years. Dissolution rates of 0.035 mm/ annum have been determined. This rate falls within the range of previously determined limestone dissolution rates in the UK, which have been described in the context of different methods of measurement and the difference in denudations rates over time.

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Production rate of cosmogenic 21Ne in quartz estimated from 10Be, 26Al, and 21Ne concentrations in slowly eroding Antarctic bedrock surfaces

Cited by 84 publications

References 34 publications

Degradation of glacial deposits quantified with cosmogenic nuclides, Quartermain Mountains, Antarctica

Degradation of glacial deposits quantified with cosmogenic nuclides, Quartermain Mountains, Antarctica

Neon diffusion kinetics in olivine, pyroxene and feldspar: Retentivity of cosmogenic and nucleogenic neon

Measurement of rates of surface lowering of limestone in the southern Pennines: an example in the Wye catchment, Derbyshire, UK

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