Minor inheritance inhibits the calibration of the 10Be production rate from the AD 1717 Val Ferret rock avalanche, European Alps

Akçar, Naki; Ivy-Ochs, S.; Deline, P.; Alfimov, V.; Kubik, P.; Christl, M.; Schlüchter, Christian (2014). Minor inheritance inhibits the calibration of the 10Be production rate from the AD 1717 Val Ferret rock avalanche, European Alps. Journal of quaternary science JQS, 29(4), pp. 318-328. John Wiley & Sons, Ltd. 10.1002/jqs.2706

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To calibrate the in situ 10Be production rate, we collected surface samples from nine large granitic boulders within the deposits of a rock avalanche that occurred in AD 1717 in the upper Ferret Valley, Mont Blanc Massif, Italy. The 10Be concentrations were extremely low and successfully measured within 10% analytical uncertainty or less. The concentrations vary from 4829 ± 448 to 5917 ± 476 at g−1. Using the historical age exposure time, we calculated the local and sea level-high latitude (i.e. ≥60°) cosmogenic 10Be spallogenic production rates. Depending on the scaling schemes, these vary between 4.60 ± 0.38 and 5.26 ± 0.43 at g−1 a−1. Although they correlate well with global values, our production rates are clearly higher than those from more recent calibration sites. We conclude that our 10Be production rate is a mean and an upper bound for production rates in the Massif region over the past 300 years. This rate is probably influenced by inheritance and will yield inaccurate (e.g. too young) exposure ages when applied to surface-exposure studies in the area. Other independently dated rock-avalanche deposits in the region that are approximately 103 years old could be considered as possible calibration sites.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Akçar, Naki and Schlüchter, Christian

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0267-8179

Publisher:

John Wiley & Sons, Ltd.

Language:

English

Submitter:

Sarah Antenen

Date Deposited:

10 Aug 2015 10:16

Last Modified:

11 Aug 2015 23:37

Publisher DOI:

10.1002/jqs.2706

Uncontrolled Keywords:

cosmogenic;mass movements;Mont Blanc;surface exposure dating

BORIS DOI:

10.7892/boris.70814

URI:

https://boris.unibe.ch/id/eprint/70814

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