Quantifying denudation rates on inselbergs in the central Namib Desert using in situ-produced cosmogenic {sup 10}Be and {sup 26}Al

Journal Article · Sat May 01 04:00:00 EDT 1999 · Geology

DOI:https://doi.org/10.1130/0091-7613(1999)027<0399:QDROII>2.3.CO;2· OSTI ID:352651

Cockburn, H A.P.; Summerfield, M A ^[1]; Seidl, M A ^[2]

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1. Univ. of Edinburgh (United Kingdom). Dept. of Geography
2. Rutgers Univ., New Brunswick, NJ (United States). Dept. of Geological Sciences

In situ-produced cosmogenic isotope concentrations in bedrock surfaces provide valuable estimates of site-specific, long-term rates of denudation and provide constraints for numerical landscape-evolution models. Measurements of cosmogenic {sup 10}Be and {sup 26}Al from graphite inselbergs in the arid to hyperarid central Namib Desert, Namibia, indicate a mean rate of summit lowering of 5.07 {+-} 1.1 m/m.y. over the past {ge} 10{sup 5} yr. The persistence of an arid climate in the region suggests that a similar rate may have prevailed for the past {approximately} 10 m.y. and possibly throughout much of the Cenozoic. Some samples have complex exposure histories that can be explained by the mode of inselberg weathering and mass wasting. The denudation rates estimated here are an order of magnitude higher than those reported for inselbergs in a significantly more humid environment in South Australia. This difference may largely be due to active salt weathering in the central Namib as a result of high levels of coastal fog precipitation.

• OSTI ID: 352651
• Journal Information: Geology, Journal Name: Geology Journal Issue: 5 Vol. 27; ISSN 0091-7613; ISSN GLGYBA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ALUMINIUM 26
BASEMENT ROCK
BERYLLIUM 10
DESERTS
EROSION
GEOLOGIC MODELS
NAMIBIA
WEATHERING