Retrogression rate of the Victoria Falls and the Batoka Gorge

Derricourt, Robin

doi:10.1038/264023a0

Cited by 31 publications

(20 citation statements)

References 12 publications

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“…The Kafue was probably not captured until the Upper Pleistocene. Derricourt (1976), Lister (1979) and Thomas and Shaw (1990) believe that the capture of the Upper Zambezi by the Middle Zambezi occurred in the Pliocene or early Pleistocene. McCarthy et al (2002) suggest that during the same time movement on faults blocked the southwards path of the Kwando and Okavango Rivers.…”

Section: Mid-late Tertiary and Quaternary Uplift And Drainage Developmentioning

confidence: 96%

The Mesozoic–Cenozoic interior sag basins of Central Africa: The Late-Cretaceous–Cenozoic Kalahari and Okavango basins

Haddon

McCarthy

2005

Journal of African Earth Sciences

146

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Section: Mid-late Tertiary and Quaternary Uplift And Drainage Developmentioning

confidence: 96%

The Mesozoic–Cenozoic interior sag basins of Central Africa: The Late-Cretaceous–Cenozoic Kalahari and Okavango basins

Haddon

McCarthy

2005

Journal of African Earth Sciences

146

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“…(Nomenclature of Zambezi establishes modern topology these lithic industries follows Lahr and Foley, 2001). This archaeological record constitutes an invaluable geochronological resource (Cotterill, 2006;Moore and Cotterill, 2010), whose potential to date key landforms was appreciated early in the 20th century by pioneering researchers (Lamplugh, 1906(Lamplugh, , 1907(Lamplugh, , 1908Clark, 1950;Bond, 1975;Derricourt, 1976). We focus on the artefacts that rim the Makgadikgadi fossil shorelines (Cotterill, 2006;Robbins and Murphy, 1998), and are preserved in river sediments across Botswana, Namibia, Zambia and Zimbabwe (du Toit, 1933;Dbcey, 1944Dbcey, , 1950Miller, 2008).…”

Section: Introductionmentioning

confidence: 99%

The Evolution and Ages of Makgadikgadi Palaeo-Lakes: Consilient Evidence From Kalahari Drainage Evolution South-Central Africa

Moore

Cotterill²,

Eckardt

2012

South African Journal of Geology

106

134

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Tiie Makgadikgadi Pans in northern Botswana are the desiccated relicts of a former major inland lake system, with fossil .shorelines preserved at five distinct elevations (~995 m, 945 m, 936 m, 920 m and 912 m). These lakes persisted in the Makgadikgadi Basin, which evolved in the Okavango-Makgadikgadi Rift Zone: the south-western extension of the East African Rift System (EARS) into northern Botswana. This paper synthesizes cross-disciplinary evidence, which reveals that the antiquity of this lake complex has been widely underestimated. It presents a Regional Drainage Evolution Model that invokes tectonically initiated drainage reorganizations as the underlying control over lake evolution. Lake formation was initiated by rift-flank uplift along the Chobe Fault, across the course of the Zambezi River, which diverted the regional drainage net into the Makgadikgadi Basin. Filling of the basin initiated a major climatic feedback mechanism that locally increased rainfall and lowered evaporation rates. This progressively enhanced water input to the basin, and most likely led to overtopping of the Chobe Horst barrier during the three highest lake stand.s, with outflow into the Zambezi River. During this period, the hydrology of the basin would have been closely analogous to modern, shallow Lake Victoria. Fragmentation of the regional drainage network by successive river captures resulted in sequential contractions of the lake to lower elevation shorelines. In turn, resultant decreases in areas of these successive lakes modulated the magniaide of the feedback mechanism. Thus, loss of the Upper Chambeshi catchment caused the lake to drop from the 990 to the 945 m level. Severance of the former link between the Kafue and Zambezi resulted in a further drop to the 936 m shoreline. Inflow declined further after the impoundment of a major lake (Palaeo-Lake Bulozi) on the Upper Zambezi River, causing contraction to the 920 m shoreline. Continued incision of the Zambezi channel into the Chobe horst barrier ultimately terminated input from this river to the Makgadikgadi depression, causing contraction of the lake below 920 m, sustained by the Cuando and Okavango prior to final desiccation. This Regional Drainage Evolution Model contradicts previous proposals that have invoked Late Pleistocene climatic forcing to explain inferred fluctuations in lake levels. The timeframe developed for the drainage reorganizations requires that the lake was initiated by ~1.40 to 0.51 Ma at the most recent (Early -Mid-Pleistocene), while archaeological evidence shows that it had contracted below the 936 m shoreline before 500 ka. This contrasts with "C and quartz luminescence dates (generally <100 ka), which require that the 945 m lake stage was extant during much of the Upper Pleistocene. The calcareous radiocarbon dates reflect multiple episodes of calcrete formation, while the young luminescence dates are ascribed to the extensive bioturbation of older Kalahari landforms.

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“…However, the recession mechanism is still incompletely understood. The rate of waterfall recession was 1Ð2-2Ð0 m a 1 for Niagara Falls from 1842 to 1905 (Gilbert, 1907), 0Ð09-0Ð15 m a 1 for Victoria Falls in Zambia (Derricourt, 1976) and 1Ð0-2Ð0 m a 1 for Ryumon Falls in Tochigi Prefecture, Japan (Yoshida and Ikeda, 1999). The factors influencing the rate of waterfall recession are not settled.…”

Section: Introductionmentioning

confidence: 99%

Recession rates of waterfalls in Boso Peninsula, Japan, and a predictive equation

Hayakawa

Matsukura

2003

Earth Surf Processes Landf

124

143

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Rates of waterfall recession, and major factors that influence the rate, were studied using waterfalls in Boso Peninsula, Japan. The mean rate of waterfall recession was estimated by determining the age and original location. The principal factor in determining the rate of waterfall recession is the ratio of the erosive force of stream to the bedrock resistance. This is expressed in terms of measurable variables, which include the discharge (drainage area and precipitation), the width and height of the waterfall, and the unconfined compressive strength of the bedrock. An empirical equation connecting the force/resistance ratios and the rates of waterfall recession is derived.

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Retrogression rate of the Victoria Falls and the Batoka Gorge

Cited by 31 publications

References 12 publications

The Mesozoic–Cenozoic interior sag basins of Central Africa: The Late-Cretaceous–Cenozoic Kalahari and Okavango basins

The Mesozoic–Cenozoic interior sag basins of Central Africa: The Late-Cretaceous–Cenozoic Kalahari and Okavango basins

The Evolution and Ages of Makgadikgadi Palaeo-Lakes: Consilient Evidence From Kalahari Drainage Evolution South-Central Africa

Recession rates of waterfalls in Boso Peninsula, Japan, and a predictive equation

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