River history and tectonics

Vita‐Finzi, Claudio

doi:10.1098/rsta.2011.0605

Cited by 17 publications

(6 citation statements)

References 67 publications

(69 reference statements)

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“…Exploring the interplay between these controls of hydrological dynamics, our tnodel reveals how tectonic changes to river topology exercised first order control over palaeo-lake evolution (with ancillary controls of local climate over the largest lake stands). This finding concurs with evidence collated across the world's rivers, testifying to how tectonism has reshaped continental drainage (Potter and Hamlin, 2006;Vita-Finzi, 2012). This finding is not surprising considering burgeoning evidence, accumulated since the early 20th century, for active rifting across the Makgadikgadi Basin and south-central Africa (Haddon and McCarthy, 2005;Kinabo et al, 2008 and references therein).…”

Section: Introductionsupporting

confidence: 84%

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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Section: Introductionsupporting

confidence: 84%

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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“…River channels are very dynamic features. They can alter their shape in response to changes in sea level, earth movements and the supply of water and sediment from their headwaters [37][38][39][40]. Rivers that carry mainly sand and gravel tend to be wide and shallow, with numerous mid-channel bars of sand and gravel (Figure 4a).…”

Section: Evidence From Riversmentioning

confidence: 99%

When the Land Sings: Reconstructing Prehistoric Environments Using Evidence from Quaternary Geology and Geomorphology, with Examples Drawn from Fluvial Environments in the Nile and Son Valleys

Williams

2022

Quaternary

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Geomorphic evidence from rivers and lakes can help explain past changes in the locations of archaeological sites as well as environmental and climatic changes in their catchment areas. Examples drawn from the Blue and White Nile valleys in northeast Africa and from the Son and Belan valleys in north-central India reveal how Quaternary climatic fluctuations in the headwaters of these rivers are reflected in changes in river channel patterns downstream as well as in the type of sediment transported. Soils and sediments that contain prehistoric and historic artefacts can be analysed to show the type of environment in which the artefacts accumulated. Beds of volcanic ash may preserve former landscapes and their fossil remains and can provide a synchronous time marker against which to assess changes in the archaeological record. The pattern and tempo of past sea level fluctuations has controlled the distribution of coastal archaeological sites and helps to explain the absence of certain Holocene Neolithic sites in southeast Asia. Disturbance of archaeological sites by plants and animals, especially termites in tropical regions, can affect the stratigraphic and chronological integrity of the site.

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“…The Himalaya, a seismo-tectonically dynamic orogenic belt, exhibits a multitude of neo-tectonic activities in certain localized sectors along with varying seismic patterns (Srivastava et al 2016;Shankar et al 2020). Coupled with climatic and surface processes, these tectonic influences, functioning at variable spatio-temporal scales, tend to shape the present-day landscapes along the entire Himalayan belt (Nakata 1972(Nakata , 1975Finzi 2012;Thakur 2013). The tectonism of this complex rugged landscape affects the nature of the river channels (Singh et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Lithological and tectonic response on catchment characteristics of Rishi Khola, Sikkim, India

Saha

Neogy²,

Kar

et al. 2021

J. Mt. Sci.

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Rishi Khola, a sub-watershed of Teesta river, traverses along the Main Central Thrust (MCT) with a multitude of litho units and structural entities. This study examines the impact of tectonic and lithologic controls in configuring the catchment characteristics of Rishi Khola, Sikkim, India. Corrected SRTM 30 m DEM and Landsat 8 satellite image have been used for extracting the river network, preparing the sub-catchments, the longitudinal profile and thereby calculating the morphotectonic indices. An aggregated tectonic index (ATI) has been prepared to map the intensity of tectonic perturbations in the fluvial environment using the entropy weightage method (EWM) and Weighted Linear Combination (WLC). The undulating nature of the longitudinal profile with prominent knick points confirms the presence of tectonic disturbances and lithological variations. From all the computed morphotectonic indices and the ATI, it has been evident that the region has experienced surface deformations. When viewed at the entire catchment, the morphotectonic indices suggest ample responses to the tectonic perturbations due to the dominance of lithology-controlled hill slope processes and fluvial erosion. The spatiality of the tectonic sensitiveness is rather concentrated into certain pockets of differential stress field formed due to fault thrusting of the Himalayas. The study chiefly focuses on the peculiarity of the watershed which displays a complex response of tectonic and rock structure; wherein the proposed methodology has been successful in excavating such complex responses around the Himalayan thrusts.

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River history and tectonics

Cited by 17 publications

References 67 publications

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

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

When the Land Sings: Reconstructing Prehistoric Environments Using Evidence from Quaternary Geology and Geomorphology, with Examples Drawn from Fluvial Environments in the Nile and Son Valleys

Lithological and tectonic response on catchment characteristics of Rishi Khola, Sikkim, India

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