Review of engineering, hydrogeological and vadose zone hydrological aspects of the Lanseria Gneiss, Goudplaats-Hout River Gneiss and Nelspruit Suite Granite (South Africa)
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- 作者：Matthys A. Dippenaar ; J. Louis van Rooy
- 关键词：ca. ; Circa (approximately) ; DWA ; Department of Water Affairs (previously DWAF) ; DWAF ; Department of Water Affairs and Forestry (now DWA) ; G-HRG ; Goudplaats-Hour River Gneiss (Suite) ; JGD ; Johannesburg Granite Dome ; KNP ; Kruger National Park ; Ma ; Million years ; NGA ; National Groundwater Archive ; NGRS ; Ngwenyeni Northern Granites Research Supersite ; KNP ; s.l. ; Sensu lato in the broad sense (as opposed to s.s.) ; s.s. ; Sensu stricto in the strict sense (as opposed to s.l.) ; SANParks ; South African N
- 刊名：Journal of African Earth Sciences
- 出版年：March, 2014
- 年：2014
- 卷：91
- 期：Complete
- 页码：12-31
- 全文大小：3735 K
文摘
Three major basement granites of South Africa, viz. the Lanseria Gneiss of the Johannesburg Dome Granite, the Goudplaats-Hout River Gneiss and the Nelspruit Suite, are compared in terms of existing and new geotechnical and hydrogeological data. Typical weathering profiles based on landform and climate are deduced, denoting typical engineering and hydrogeological behaviour. Finally, the vadose zone behaviour of the basement granites are described with the aim on better understanding of the behaviour of these systems under variable saturation. Ephemeral hillslope wetlands, seepage lines and catenas are specifically addressed as associated hydrological influences, as well as the associated processes of translocation forming duplex soils and pedogenesis forming ferricrete. The final summarised findings depict low plasticity and expansiveness of granites with the most notable geotechnical influences being collapsibility, dispersive behaviour, seepage and difficult excavation. Hydrologically, secondary porosity prevails and younger structures or intrusions govern groundwater occurrence. The vadose zone comprises thick fractured rock to be included in modelling with the soil zone having saturated conductivity typically in the order of 1 脳 10鈭?/sup>4 to 1 脳 10鈭?/sup>5 m/d.