Journal article

Chronology and controls of avulsion along a mixed bedrock-alluvial river

Stephen Tooth, Helena Rodnight, Geoff AT Duller, Terence S McCarthy, Philip M Marren, Dion Brandt

GEOLOGICAL SOCIETY OF AMERICA BULLETIN | GEOLOGICAL SOC AMER, INC | Published : 2007

Abstract

Avulsions are most characteristic of aggrading fluvial systems, but along the Klip River, subhumid eastern South Africa, abandonment and re-establishment of meander belts occurs under conditions of negligible vertical aggradation. Channel banks are fully alluvial, but the bed is grounded on sandstone and shale, so that during meander migration, alluvium ∼2-4 m thick is deposited by lateral accretion on a near-planar bedrock surface. Abandoned meander belts up to 4 km long are present where floodplain gradient increases by a factor of 2-3 and floodplain sediments change from dominantly mud to sand. Optically stimulated luminescence (OSL) and radiocarbon ages from abandoned channel fills indic..

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University of Melbourne Researchers