View/Open - University of Zululand Institutional Repository
View/Open - University of Zululand Institutional Repository View/Open - University of Zululand Institutional Repository
188 Table K1: Some geological formations in South Africa. with special reference to NataUKwaZulu (continued). Stratigraphy Geological formation Uthology Karoo Supergroup Ecca Group Normandien Mudstones and (continued) Formation (Estcourt shales Formation) Volksrust Formation Mudstones and shales Permian Vryheid Formation Sandstones and shales Pietermaritzburg Shales Shale Formation Carboniferous Dwyka Group Dwyka TIllite TIllites/diamictites. Formation conglomerates, sandstones. siltstones and mudstones Cape Supergroup Witteberg Group Msikaba Formation Sandstones . Devonian Ordovician- Natal Group Mariannhill Sandstones, Siluraian Formation quartzites, Durban Formation shales and conglomerates Mokolian Various groups, Various formations Granites, gneisses, Vaalian metamorphic schists and Randian suites and amphibolites Swazian complexes - (Mapumulo, Mzimkulu. Ngoye. Tugela, Mfongozi. Nsuzi, Mozaan and Nondweni) Source: Maud. R.R.• 1995. Unpublished document. Drennan Maud and Partners. Durban. Note: (i) Descending order in the above table implies increasing geological age. (ii) The term "Dwyka Tillite" per se is no longer in common use in the geological literature. The term "Karoo" appears in older texts as "Karroo". The latter spelling has been discontinued. Brackets denote a pending change in nomenclature.
189 fault-bounded blocks, although horst and graben (block and basin) structures are present in the northern central part of this area. In the north, the structure of the Lebombo area is mainly that of a seaward faulted flexure. The tilted fault blocks in general are tilted in a seaward direction, the amount of tilt of the individual blocks usually increasing in this direction to a maximum of about 15 0 • Locally however, blocks can tilt in an inland direction, as in the major block north of Port Shepstone and between the Thukela and Mlalazi rivers. Fault zones may vary in width from less than a metre in the case of small faults, to 10 m and more in respect of large faults such as the Eteza Fault north of Empangeni. Fault zones may comprise either silicified or kaolinised fault breccia. The interior of the province by contrast, is unfaulted, the rocks of the Karoo Supergroup generally having a regional bedding dip of less than about 3 0 in a westerly or inland direction. The rocks of the Proterozoic and Archaeozoic basement - recently renamed beneath the sediments of the Natal Group and the Karoo Supergroup, where exposed, are usually strongly lineated, and are steeply foliated in rock types other than batholithic granite intrusions. All rocks in the region are jointed (a discontinuity on which no significant movement has taken place), to a greater or lesser degree. Faults and joints being sites of weakness in the rocks, tend to be erosion-susceptible and thus very frequently have rivers and streams aligned along them. In some parts of the province, the drainage pattern is fully controlled by the distribution of faults and joints. Faults and joints have a very important effect on the gioundwater situation (as discussed later). In the tilted fault block coastal area, the inclination of the bedding planes of sedimentary rocks where so tilted (particularly sandstones), has a marked influence on the movement of groundwater, as the direction of such movement is generally in the down-dip direction of the bedding planes. • Distribution of geological formations Away from the faulted coast and coastal hinterland areas of Natal/KwaZulu - where different rock types are very frequently juxtaposed as a result of the faulting - increases in altitude result in a simple elevation in the Iithostratigraphic sequence. Overall, the granitic Proterozoic and older rocks form a fairly broad belt on the inner margin of the coastal faulted zone. These rocks occur at the coast in the south but at an increasing distance from the coast in a northerly direction, except where they are returned to this
- Page 142 and 143: 139 Source: (i) After Ardington, E.
- Page 144 and 145: 141 i111_1illll1l noted above!. are
- Page 146 and 147: 143 (ii) The Directorate of Land an
- Page 148 and 149: 145 1111111111111 the Board will as
- Page 150 and 151: 147 Table J40: Administrative regio
- Page 152 and 153: 149 111II1.llllIf:J Government Noti
- Page 154 and 155: 151 111I.lIllllil1 Government agenc
- Page 156 and 157: 153 Table J43: Joint Services Board
- Page 159 and 160: 156 Source: (i) After Jenkin, F. (e
- Page 161 and 162: 158 Chief Directorate: Administrati
- Page 163 and 164: Source: See also: Note: 160 Afterth
- Page 165 and 166: 162 off low - responsible inter ali
- Page 167 and 168: 11111.'.111:11111 164 If it became
- Page 169 and 170: tlll••••I:IB11 NOTES: 166
- Page 171 and 172: Contents 167 CHAPTER 11: GROUNDWATE
- Page 173: Tables 169 Table K1: Some geologica
- Page 178 and 179: 174 Bate, 1992}*. The use of water
- Page 180 and 181: 176 X313, Pretoria, 0001; as well a
- Page 183 and 184: 179 a particular site, then a stati
- Page 185 and 186: 181 111...1[111 of streams and rive
- Page 187 and 188: 183 good. with a total dissolved so
- Page 189 and 190: (iii) Holocene sands lQuaternary) 1
- Page 191: 187 Table K1: Some geological forma
- Page 195 and 196: 191 11.6.4 Aquifer characteristics
- Page 197 and 198: 193 coarse and the latter, fine and
- Page 199 and 200: 195 111.BIII!I!111 The yields of bo
- Page 202 and 203: 11...,].11 198 11.7 Methods of grou
- Page 205 and 206: 201 11...11111 Table K3: Methods of
- Page 207 and 208: 203 boreholes are drilled for both
- Page 209 and 210: 205 1111111111'.1 3838. The borehol
- Page 211 and 212: 207 11.11 Standards applicable to t
- Page 213 and 214: (a) Gravity springs 209 Gravity spr
- Page 215: Table K4: Spring discharge in the V
- Page 218: 214 Table K5: The number of ephemer
- Page 222 and 223: JJI...lllJll 218 (h) Some of the wa
- Page 224 and 225: i'•••liDl Group E: Pure water
- Page 226 and 227: 222 Bond, Van Wyk proposed the foll
- Page 228 and 229: 1[11....11.,1 224 (b) Chlorides are
- Page 230 and 231: 226 Source: Edwards, T.J., 1989. Pe
- Page 232 and 233: 228 also obtainable from the Ground
- Page 234 and 235: Ill1••lll1l 230 • Hofkes, EH.
- Page 236 and 237: 232 • Vegter, J.R., 1995. Groundw
- Page 238 and 239: 234 • Meyer, R. and Godfrey, l.,
- Page 240 and 241: Springs 236 • Africa Co-operative
188<br />
Table K1: Some geological formations in South Africa. with special reference to<br />
NataUKwaZulu (continued).<br />
Stratigraphy Geological formation Uthology<br />
Karoo Supergroup Ecca Group Normandien Mudstones and<br />
(continued) Formation (Estcourt shales<br />
Formation)<br />
Volksrust Formation Mudstones and<br />
shales<br />
Permian Vryheid Formation Sandstones and<br />
shales<br />
Pietermaritzburg Shales<br />
Shale Formation<br />
Carboniferous Dwyka Group Dwyka TIllite TIllites/diamictites.<br />
Formation conglomerates,<br />
sandstones.<br />
siltstones and<br />
mudstones<br />
Cape Supergroup Witteberg Group Msikaba Formation Sandstones .<br />
Devonian<br />
Ordovician- Natal Group Mariannhill Sandstones,<br />
Siluraian Formation quartzites,<br />
Durban Formation shales and<br />
conglomerates<br />
Mokolian Various groups, Various formations Granites, gneisses,<br />
Vaalian metamorphic schists and<br />
Randian suites and amphibolites<br />
Swazian complexes -<br />
(Mapumulo,<br />
Mzimkulu. Ngoye.<br />
Tugela, Mfongozi.<br />
Nsuzi, Mozaan and<br />
Nondweni)<br />
Source: Maud. R.R.• 1995. Unpublished document. Drennan Maud and Partners.<br />
Durban.<br />
Note: (i) Descending order in the above table implies increasing geological<br />
age.<br />
(ii) The term "Dwyka Tillite" per se is no longer in common use in the<br />
geological literature. The term "Karoo" appears in older texts as<br />
"Karroo". The latter spelling has been discontinued. Brackets<br />
denote a pending change in nomenclature.
Change language