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A paleo-environmental record covering the last 16 ka (16,000 cal yrs BP) from the eastern areas of the summer rainfall region in South Africa is presented. This area is until now sparsely investigated due to the lack of well preserved natural archives. For this study, we used a peat section from a wetland situated close to the Drakensberg escarpment, where the high annual rainfall amounts supported a continuous peat accumulation since c. 16 ka. One peat core was analysed in terms of fossil pollen composition, carbon and nitrogen content, isotope composition (δ13C, δ15N) and microscopic charcoal concentration. The greatest degree of temporal resolution was achieved from the late Pleistocene and early Holocene section, where proxy-records indicate relatively dry conditions between ca. 16–13.7 ka, 12.8–10.5 ka, 9.5–8.2 ka, and wet conditions between c. 13.7–12.8 ka and 10.5–9.5 ka. A weak moisture signal is also evident at c. 8.2–7.5 ka. The late Pleistocene to early Holocene period was relatively cool, while conditions became generally warmer after 11–8 ka. The interpretation of the mid- and late-Holocene sequence is limited due to a slow accumulation and low sample resolution, but the available data suggest relatively dry conditions until c. 1.5 ka, followed by more humid conditions until c. 0.5 ka. We suggest that the millennial scale variability within the record can be attributed to shifts in the circulation systems dominating the region, i.e. the latitudinal movements of the inter-tropical convergence zone (ITCZ) and the dynamics of the mid-latitude low pressure belts.

Data from stalagmites in the Makapansgat Valley, South Africa, document regional climatic change in southern Africa in the Late Pleistocene and Holocene. A new TIMS U-series dated stalagmite indicates speleothem growth from 24.4 to 12.7 ka and from 10.2 to 0 ka, interrupted by a 2.5 ka hiatus. High-resolution oxygen and carbon stable isotope data suggest that postglacial warming was first initiated ∼17 ka, was interrupted by cooling, probably associated with the Antarctic Cold Reversal, and was followed by strong warming after 13.5 ka. The Early Holocene experienced warm, evaporative conditions with fewer C4 grasses. Cooling is evident from ∼6 to 2.5 ka, followed by warming between 1.5 and 2.5 ka and briefly at ∼AD 1200. Maximum Holocene cooling occurred at AD 1700. The new stalagmite largely confirms results from shorter Holocene stalagmites reported earlier. The strongest variability superimposed on more general trends has a quasi-periodicity between 2.5 and 4.0 ka. Also present are weaker ∼1.0 ka and ∼100-year oscillations, the latter probably solar induced. Given similarities to the Antarctic records, the proximate driving force producing millennial- and centennial-scale changes in the Makapansgat record is postulated to be atmospheric circulation changes associated with change in the Southern Hemisphere circumpolar westerly wind vortex.

Cosmogenic aluminum-26 and beryllium-10 burial dates of low-lying fossiliferous breccia in the caves at Sterkfontein, South Africa, show that associated hominid fossils accumulated in the Lower Pliocene. These dates indicate that the skeleton StW 573 and newly discovered specimens from Jacovec Cavern have much the same age: approximately 4 million years. These specimens are thus of an age similar to Australopithecus anamensis from East Africa.

Late Pleistocene variations in rainfall in subtropical southern African are estimated from sediments preserved in the Pretoria Saltpan, a 200000 year-old closed-basin crater lake on the interior plateau of South Africa. We show that South African summer rainfall covaried with changes in southern hemisphere summer insolation resulting from orbital precession. As predicted by orbital precession geometry (Berger, 1978), this South African record is out of phase with North African palaeomonsoon indices (Street and Grove, 1979; Rossignol-Strick, 1983; McIntyre et al., 1989); the amplitude of the rainfall response to insolation forcing agrees with climate model estimates (Prell and Kutzbach, 1987). These results document the importance of direct orbital insolation forcing on both subtropical North and South African climate as well as the predicted antiphase sensitivity to precessional insolation forcing.

One of the most urgent problems confronting future development in the PWV metropolitan region is the provision of low-cost housing for its large and rapidly increasing homeless population. Priorities for the location of this housing are set not only by considerations of land availability and infrastructure, but also by new models of urban development, and by the serious constraints imposed by geotechnical factors. Among the most important of these are the distribution of dolomitic rocks, with their associated problems of instability resulting from subsurface karst weathering, and areas of shallow undermining in which government regulations have hitherto precluded housing development. In view of the costs of assessing the risks associated with the construction of high-density housing and accompanying infrastructure on dolomite, and the fact that the risk of sinkhole development can never be completely excluded even after detailed investigation, it is proposed that the dolomitic “girdle” surroundin...

The Pretoria Saltpan is a circular crater 1130 m in diameter and is situated some 40 km N of Pretoria (lat. 25°34′30″/long. 28°04′59″E). A recent tube sampling and core drilling programme has revealed an infilling consisting of some 90 m of fine lacustrine sediments (chiefly organic muds, underlain below 30 m depth by micrites) which rest upon a further 61 m of coarse clastic debris. Granite bedrock was encountered at − 151 m. Broad sedimentary zones correspond with major phases in the evolution of the crater lake. Superimposed cyclical patterns of accumulation reflect environmental changes on millenial to seasonal timescales. 14C age determinations on algal debris from the upper 20 m of the core indicate a mean rate of sedimentation of about 1 m/2000 yr, suggesting that the lacustrine sequence may span almost 200,000 yr. Over this period major environmental changes are apparent from sedimentological, chemical, mineralogical and isotopic analyses of the core and studies of the pollen spectra and diatom assemblages present within it. This long continental sequence is therefore providing a high-resolution palaeoenvironmental record for southern mid-latitudes over much the same period as is covered by the Vostok ice-core in Antarctica.

In an article (“Great age suggested for South African hominids,” News of the Week, 25 April, p. [562][1]) published in conjunction with our announcement of new absolute dates and early hominid specimens from Sterkfontein (“Lower Pliocene hominid remains from Sterkfontein,” T. C. Partridge et al. , Research Article, 25 April, p. [607][2]), Ann Gibbons writes, “co-author Clarke says that Little Foot does not resemble A. anamensis in crucial aspects. And he says that the new Jacovec fossils, which [co-author] Granger dated to 4 million years ago, may represent two types of australopithecines—suggesting a diversity of 4-million-year-old hominids.” These statements by Gibbons are incorrect. Clarke told Gibbons that it was not possible at this stage to compare the australopithecines at Jacovec Cavern with Australopithecus anamensis because the most diagnostic part of A. anamensis , the mandible, was not represented in the Jacovec fossil sample. Furthermore, the Little Foot skeleton, including the mandible, is still embedded in breccia and thus cannot yet be compared directly to A. anamensis or any other Australopithecus species. In the text of our paper, we observed that there are two forms of femur represented in the Member 4 breccia of Sterkfontein and that one of these, the long-necked form, is present in Jacovec. We state, “This suggests that two different forms of Australopithecus might be represented by the Sterkfontein femurs.” We did not say, and do not even consider, that two forms are currently represented in the Jacovec sample. We take this opportunity to correct other misconceptions about the dating. The stratigraphy at Sterkfontein is not particularly complex and is well documented in numerous surface and underground exposures, as well as by five stratigraphic boreholes [see ( 2 , 5 ) in our Research Article]. The validity of our results is, however, constrained by local relationships and not by overall stratigraphy. The hominid-bearing deposits that we dated were the first to accumulate after the cave opened to the surface via two vertical shafts. The sampling sites are in deep chambers whose dolomite roofs remain intact and exceed 20 m in thickness. These deposits overlie a basal sequence (Member 1) made up of roof-collapse blocks and insoluble components of the dolomite bedrock (mainly manganese and iron oxides) that accumulated as a fine residue during phreatic solution (i.e., below the water table); no extracavernous elements have been found within Member 1. Careful examination of the surface of the Sterkfontein hill, which consists largely of outcropping dolomite bedrock, as well as the shaft conduits themselves, has failed to reveal any infill deposits that could have contaminated soil entering the cave from the hill slopes outside. The shafts themselves are dolomite-walled and vertical and are not a source of quartz particles. It must also be pointed out that contamination from infills at depths shallower than 20 m would result in a reduction in apparent age, as such deposits would, regardless of their true age, have accumulated recent 26Al and 10Be. The sequence within the Silberberg Grotto that contains the skeleton is well layered and includes four thick and laterally persistent layers of hard calcite flowstone that occur within a vertical interval of 3 m; after each of the intervening soil layers fell from above, it was sealed off by the next flowstone, precluding vertical mixing. The skeleton is sandwiched between the second and third flowstones, both of which were intact when our excavations began. # Response {#article-title-2} The article should have said that there were two types of australopithecines at Sterkfontein rather than in the Jacovec caverns, and I regret the error. On the question of hominid diversity in Africa, I asked co-author Ron Clarke if the skeleton called Little Foot (Stw 573) was a member of Australopithecus anamensis , which lived in East Africa at the same time, and he replied in a telephone interview: “No, we cannot say it is like anamensis .” He added that he did not have the “right parts” to settle the taxonomic question, but then continued, “This was another indication that there were many species of australopithecines ranging all over Africa, just as there were multiple species of Miocene apes. There were multiple species of ape-men.” I gave all the authors an opportunity to check facts in the final draft of the article. Granger made minor corrections on the dating, Partridge did not respond to e-mail or a telephone message for 4 days, which was after deadline, and Clarke was unavailable. [1]: /lookup/doi/10.1126/science.300.5619.562 [2]: /lookup/doi/10.1126/science.1081651

(1967). Gravels and Terraces of the Lower Vaal River Basin. South African Geographical Journal: Vol. 49, No. 1, pp. 21-38.

Cave opening at several of the South African hominid sites occurred through incision and valley widening in one current erosion cycle. Measurements of rates of cyclic nickpoint migration and valley flank recession make possible time-place transpositions, and the approximate date of cavern opening can be determined for each site. In each case this date represents a terminus post quem for the accumulation of hominid-bearing deposits.