scholarly journals Effects of long soil surface residence times on apparent cosmogenic nuclide denudation rates and burial ages in the Cradle of Humankind, South Africa

2019 ◽  
Vol 44 (15) ◽  
pp. 2968-2981 ◽  
Author(s):  
T.V. Makhubela ◽  
J.D. Kramers ◽  
D. Scherler ◽  
H. Wittmann ◽  
P.H.G.M. Dirks ◽  
...  
Keyword(s):  
South Africa ◽  
Soil Surface ◽  
Residence Times ◽  
Cosmogenic Nuclide ◽  
Denudation Rates ◽  
Cradle Of Humankind

scholarly journals What happens after the catchment caught the storm? Hydrological processes at the small, semi-arid Weatherley catchment, South-Africa

2005 ◽  
Vol 2 ◽  
pp. 237-241 ◽  
Author(s):  
S. Uhlenbrook ◽  
J. Wenninger ◽  
S. Lorentz
Keyword(s):  
South Africa ◽  
Electrical Resistivity ◽  
Soil Moisture ◽  
Experimental Techniques ◽  
Storm Event ◽  
Residence Times ◽  
Hydrological Response ◽  
Flow Paths ◽  
Flow Pathways ◽  
Semi Arid

Abstract. The knowledge of water flow pathways and residence times in a catchment are essential for predicting the hydrological response to a rain storm event. Different experimental techniques are available to study these processes, which are briefly reviewed in this paper. To illustrate this, recent findings from the Weatherley catchment a 1.5 km2 semi-arid headwater in South-Africa, are reported in this paper. Beside classical hydrometric measurements of precipitation and runoff different experimental techniques were applied to explore flow paths (i.e. soil moisture and groundwater measurements, natural tracers, and 2-D electrical resistivity tomographies (ERT)).

scholarly journals <sup>10</sup>Be systematics in the Tsangpo-Brahmaputra catchment: the cosmogenic nuclide legacy of the eastern Himalayan syntaxis

2017 ◽  
Author(s):  
Maarten Lupker ◽  
Jérôme Lavé ◽  
Christian France-Lanord ◽  
Marcus Christl ◽  
Didier Bourlès ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Sediment Flux ◽  
Coarse Grained ◽  
The Tibetan Plateau ◽  
Data Set ◽  
Denudation Rate ◽  
Cosmogenic Nuclide ◽  
Denudation Rates ◽  
The Impact ◽  
Eastern Himalayan Syntaxis

Abstract. The Tsangpo-Brahmaputra River drains the eastern part of the Himalayan range, flowing from the Tibetan Plateau through the eastern Himalayan syntaxis and downstream to the Indo-Gangetic floodplain. As such it is a unique natural laboratory to study how denudation and sediment production processes are transferred to river detrital signals. In this study, we present a new 10Be data set to constrain denudation rates across the catchment and to quantify the impact of rapid erosion within the syntaxis region on cosmogenic nuclide budgets and signals. 10Be denudation rates span around two orders of magnitude across the catchments (ranging from 0.03 mm/yr to > 4 mm/yr) and sharply increase as the Tsangpo-Brahmaputra flows across the eastern Himalaya. The increase in denudation rates however occurs ~ 150 km downstream of the Namche Barwa-Gyala Peri massif (NBGPm), an area which has been previously characterized by extremely high erosion and exhumation rates. We suggest that this downstream lag is mainly due to the physical abrasion of coarse grained, low 10Be concentration, landslide material produced within the syntaxis that dilutes the upstream high concentration 10Be flux from the Tibetan Plateau only after abrasion has transferred sediment to the studied sand fraction. A simple abrasion model produces typical lag distances of 50 to 150 km compatible with our observations. Abrasion effects reduce the spatial resolution over which denudation can be constrained in the eastern Himalayan syntaxis. In addition, we also highlight that denudation rate estimates are dependent on the sediment connectivity, storage and quartz content of the upstream Tibetan Plateau part of the catchment which tends to lead to an overestimation of downstream denudations rates. Taking these effects into account we estimate a denudation rates of ca. 2 to 5 mm/yr for the entire syntaxis and ca. 4 to 28 mm/yr for the NBGPm, which is significantly higher than other to other large catchments. Overall, 10Be concentrations measured at the outlet of the Tsangpo-Brahmaputra in Bangladesh suggest a sediment flux between 780 and 1430 Mt/yr equivalent to a denudation rate between 0.7 and 1.2 mm/yr for the entire catchment.

scholarly journals Modelling and control of potable water chlorination

2002 ◽  
Vol 46 (9) ◽  
pp. 103-108 ◽  
Author(s):  
A. Pastre ◽  
M. Mulholland ◽  
C.J. Brouckaert ◽  
C.A. Buckley ◽  
M.-V. Le Lann ◽  
...  
Keyword(s):  
South Africa ◽  
Strong Influence ◽  
Potable Water ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Chlorine Concentration ◽  
Residence Times ◽  
Predictive Controller ◽  
Water Chlorination ◽  
And Control

The Umgeni Water Wiggins water treatment plant feeds the southern areas of Durban in South Africa and has a maximum treatment capacity of about 350 Ml/d. Two interconnected reservoirs at this facility hold treated water before it enters the distribution network. Because of the variable demand, the reservoir levels and residence times undergo considerable variation. This has a strong influence on the free chlorine concentration in the water leaving the reservoir, which should be 0.8 to 1.2 mg/l, to ensure an adequate disinfection potential within the network. This paper describes a model which accounts for the observed variations of chlorine concentration, and will form the basis of a predictive controller for the chlorine concentration in the outlet.

scholarly journals Millennial-scale denudation rates in the Himalaya of Far Western Nepal

2019 ◽  
Author(s):  
Lujendra Ojha ◽  
Ken L. Ferrier ◽  
Tank Ojha
Keyword(s):  
Stream Power ◽  
Denudation Rate ◽  
The Past ◽  
Cosmogenic Nuclide ◽  
Northern India ◽  
Denudation Rates ◽  
Cosmogenic 10Be ◽  
Channel Steepness ◽  
The Himalaya ◽  
Millennial Scale

Abstract. Over the past two decades, rates and patterns of Himalayan denudation have been documented through numerous cosmogenic nuclide measurements in central and eastern Nepal, Bhutan, and northern India. To date, however, few denudation rates have been measured in Far Western Nepal – a ~ 300-km-wide region near the center of the Himalayan arc – which presents a significant gap in our understanding of Himalayan denudation. Here we report new catchment-averaged millennial-scale denudation rates inferred from cosmogenic 10Be in fluvial quartz at seven sites in Far Western Nepal. The inferred denudation rates range from 385 ± 31 t km−2 yr−1 (0.15 ± 0.01 mm yr −1) to 8737 ± 2908 t km−2 yr−1 (3.3 ± 1.1 mm yr−1), and, in combination with our analyses of channel topography, are broadly consistent with previously published relationships between catchment-averaged denudation rates and normalized channel steepness across the Himalaya. These data show a weak correlation with catchment-averaged specific stream power, consistent with a Himalaya-wide compilation of previously published stream power values. Together, these observations are consistent with a dependence of denudation rate on both tectonic and climatic forcings, and represent a first step toward filling an important gap in denudation rate measurements in Far Western Nepal.

Development of cosmogenic nuclide capabilities in South Africa and applications in Southern African geomorphology

2020 ◽  
pp. 1-20 ◽  
Author(s):  
Tebogo V. Makhubela ◽  
Stephan R. Winkler ◽  
Vela Mbele ◽  
Jan D. Kramers ◽  
Rivoningo R. Khosa ◽  
...  
Keyword(s):  
South Africa ◽  
Cosmogenic Nuclide

scholarly journals Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Lee R Berger ◽  
John Hawks ◽  
Darryl J de Ruiter ◽  
Steven E Churchill ◽  
Peter Schmid ◽  
...  
Keyword(s):  
South Africa ◽  
Single Species ◽  
Homo Erectus ◽  
Cranial Morphology ◽  
Human Populations ◽  
Early Homo ◽  
Homo Habilis ◽  
Cave System ◽  
Unknown Species ◽  
Cradle Of Humankind

Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa.

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