No abstract availablehttp://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1468-0459hb201

Holmes, Peter J.

Nel, Werner

Seely, Mary

Sumner, P.D. (Paul)

UPSpace at the University of Pretoria

1SOUTHERN AFRICAN GEOMORPHOLOGY: LOOKING BACK, MOVINGFORWARDPAUL D. SUMNER1, WERNER NEL2, PETER J. HOLMES3 AND MARY SEELY41Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Hatfield, South Africa2Department of Geography and Environmental Science, University of Fort Hare, Alice, South Africa3Department of Geography, University of the Free State, Bloemfontein, South Africa4Gobabeb Research and Training Centre, Walvis Bay, NamibiaGeomorphology in southern Africa has evolved into a unique, distinct and recognised disciplinewithin the earth science context. Since its inaugural meeting in 1988, the Southern AfricanAssociation of Geomorphologists (SAAG) has comprised of a relatively small but dynamicacademic community convening biennial conferences at locations across the sub-continent. It isundoubtedly fitting that the venue for the most recent (2012) conference of SAAG was theGobabeb Research and Training Centre in the Namibian Desert. The Centre has a long standingreputation for facilitating research excellence (see Henschel and Lancaster 2013) and it was atthis conference that the proposal for this special issue was presented. While the theme of theconference was ‘Celebrating 50 years of Namib Desert Research’ the program was by no meanslimited to papers on arid geomorphology. Southern African geomorphological research hasalways been diverse in nature but, whatever the specific context of geomorphic research, thebroader (regional) context is one of dryness. The conference also served as a platform for thelaunch of a new book entitled Southern African Geomorphology; Recent Trends and NewDirections, edited by Peter Holmes and Michael Meadows (Holmes and Meadows 2012). This isthe first new, comprehensive title devoted to southern African geomorphology since thepublication, 25 years ago, of Bernie Moon and George Dardis’ edited volume on TheGeomorphology of Southern Africa (Moon and Dardis 1988). Both books serve as definitive textson the state of southern African geomorphology and its contribution within the global arena.Over the past two decades, the ‘internationalisation’ of geomorphic research in southern Africahas been facilitated by the political developments of the early nineties that saw the end ofacademic boycotts and greater interest in conferences hosted within the region. This period hasbeen characterised by a phenomenal increase in collaborations between southern Africangeomorphologists and colleagues from international institutions, particularly those based in theUnited Kingdom, but also in Europe and America. In Holmes and Meadows (2012), 11 of the 24contributing authors, and no fewer than eight of the 13 referees are scientists based outside ofsouthern Africa. At the Gobabeb gathering, approximately half of the 35 oral and 18 posterpresentations were authored or co-authored by foreign delegates. Of the 53 delegates whopresented, 19 were emerging researchers and the Oxford group’s training programme broughtemerging geomorphologists together on the Namib dunes to learn more about ground-penetratingradar and its application. Outside of the arid theme, Southern African geomorphologists and theirco-workers embrace a number of diverse topics including weathering, cold climates and climatechange, hydro-geomorphology, coastal and karst geomorphology and degradation (seeBeckedahl et al. 2002). With the research heritage of Gobabeb presented elsewhere (Henschel2and Lancaster 2013), this special edition portrays the ongoing geomorphological research in itsbroader sense. It mostly constitutes papers presented at Gobabeb and represents the eclecticrange of geomorphological topics which reflects the diverse nature of southern Africangeomorphological research.For this issue, some authors chose a critical review approach as their focus while other paperspresent primary data and interpretation from the field and laboratory. Eckardt et al. (2013) providean overview of the surface geology and geomorphology around Gobabeb in the Central NamibDesert. The paper introduces the major lithologies associated with the Damara Orogen ofPrecambrian and Cambrian age, followed by Tertiary sandstones and conglomerates andQuaternary Kuiseb valley conglomerates, silts and gravels. To commemorate the 50thanniversary of the Gobabeb research station and to pay tribute to the recent designation of theNamib Sand Sea as a world heritage site, Eckardt et al. (2013) also present a map to inform andguide future research and educational activities around Gobabeb.Boelhouwers and Jonsson (2013) assess the temporal threshold for thermal shock weathering.This discussion paper questions the role of thermal shock weathering in cold regions and placesrenewed emphasis on the importance of absolute temperature and measurement of strain, as wellas spatial temperature gradients. In a laboratory study, Loubser (2013) applies wetting and dryingcycles to sandstone and basalt from South Africa and Marion Island respectively. Small changesin internal rock structure are noted to have an effect on the nature of weathering and the numberof wetting and drying cycles is found to be more important than the degree to which saturationoccurs. In Antarctica, Hansen et al. (2013) show that aspect exerts a control on weathering ofblocks in a blockfield in Dronning Maud Land. The authors argue that a higher radiation budgetassociated with slope aspect and angle could drive thermal regimes and subsequent weatheringof clast faces. In the absence of abundant precipitation, ice and snow become the moisturesource in this high latitude Antarctic environment.Hedding and Sumner (2013) review and refine the diagnostic criteria for pronival ramparts. Theirpaper emanates in part from some of the controversial relict features in southern Africa andcollates rampart characteristics from active field sites near the South African research bases inthe sub- and continental Antarctic, amongst others. Le Roux and Sumner (2013) draw fromseveral multi-scale studies on soil erosion in South Africa and propose a methodologicalframework for water erosion risk assessment. Three hierarchical levels are presented that rangefrom a small catchment to a national scale. While the assessment levels broadly match thoseproposed elsewhere in the globe, the framework emphasises the most feasible erosionassessment techniques and input datasets for a developing country where data are inherentlymore limited. Nel et al. (2013) assess the temporal attributes of rainfall and compare twocommonly used erosivity indexes on the tropical island of Mauritius. For the computation oferosivity, the authors find that rainfall data with the highest possible resolution should be utilisedand that the application of annual and monthly rainfall totals to assess absolute soil erosion riskwithin such an environment should be used cautiously.Reinwarth et al. (2013) present a 700-year record on the effects of climate and human impact onthe southern Cape coast inferred from lake sediments. The data show that changes in theseasonal distribution of rainfall during the Little Ice Age may have altered river discharge andincreased erosion rates and fluvial sediment transport in pre-colonial times. Enhancedsedimentation rates, increasing carbon, nitrogen, phosphorous and biogenic silica concentrations,3as well as high concentrations of proxies for allochthonous sediment input point to increasingsediment and nutrient flux into Eilandvlei from the late nineteenth century onwards. It is suggestedthat the most likely factor involved in these recent changes is land-use change and other forms ofhuman impact. This special issue also includes a paper by friends and colleagues of the lateHelga Besler (Besler et al. 2013). As a tribute to her life and work at Gobabeb, 40 years of dataon dynamics are presented on what fondly is known as Helga’s Dune. The data show changes indune behavior that appear to be related to changes in wind regime and vegetation cover of theinterdune area as a result of increased rainfall in recent years. The study demonstrates thedynamic nature of the dune tip and its sensitivity to changes in wind and sand supply.Southern African geomorphological research has increased exponentially over the last twodecades. This is reflected in recent titles (Holmes and Meadows 2012), the volume and quality ofresearch published in local and international journals, the number of collaborative projectsbetween South Africans and their colleagues abroad and the increasing proportion of foreignmembership of SAAG. This issue represents a cross-section of work being undertaken by SouthAfricans and their collaborators and substantiates our confident assertion that academicgeomorphology in our country is diverse, alive and well. The international interest in southernAfrica is demonstrated in the author profiles but of equal or possibly greater significance for thefuture are the number of contributors who are emerging researchers in the discipline. We trustthat, from this foundation, local and international interest in the geomorphology of thesubcontinent will continue to thrive into the future.AcknowledgementsWe wish to thank all the contributing authors for their efforts in ensuring quality papers and thereviewers who’s time and efforts under stringent deadlines have significantly helped to improvethe papers. We are grateful for the opportunity to collectively publish the work of southern Africangeomorphologists in a thematic issue of Geografiska Annaler: Series A, Physical Geography anda special thank you is extended to the editors-in-chief Jan Boelhouwers, for sowing the seed ofthis issue at the Gobabeb conference, and Peter Jansson and for his dedicated and professionalassistance in guiding us through the process.BiographiesPaul D Sumner, Department of Geography, Geoinformatics and Meteorology, University ofPretoria, Private Bag X20, Hatfield, 0028, South AfricaE-mail: paul.sumner@up.ac.zaWerner Nel, Department of Geography and Environmental Science, University of Fort Hare,Private Bag X1314, Alice, 5700, South AfricaE-mail: WNel@ufh.ac.za4Peter J Holmes, Department of Geography, University of the Free State, PO Box 339,Bloemfontein, 9300, South Africa,E-mail: holmespj@ufs.ac.zaMary Seely, Gobabeb Research and Training Centre, P O Box 953, Walvis Bay, NamibiaE-mail: Mary.Seely@drfn.org.naReferencesBeckedahl, H.R., Sumner P.D. and Garland, G. 2002. Southern African geomorphology: criticalchoices for the future. South African Geographical Journal, 84, 145–152.Besler, H., Lancaster, N., Bristow, C., Henschel, J., Livingstone, I., Seely, M. and White, K. 2013.Helga's Dune: 40 years of dune dynamics in the Namib Desert. Geografiska Annaler: SeriesA, Physical Geography, 95, 285-293,  doi: 10.1111/geoa.12013Boelhouwers, J.C. and Jonsson, M. 2013. Critical assessment of the 2°C min-1 threshold forthermal stress weathering Geografiska Annaler: Series A, Physical Geography, 95, 285-293.doi: 10.1111/geoa.12026Eckardt, F.D, Livingstone, I. and Seely, M., Von Holdt, J.R.C 20xx. An introduction to the surfacegeology and geomorphology around Gobabeb, Namib Desert, Namibia. GeografiskaAnnaler: Series A, Physical Geography, 95, 271-284, doi: 10.1111/geoa.12028Hansen, C.D., Meiklejohn, K.I., Nel, W., Loubser, M.J. and  Van der Merwe, B.J. 2013. Aspect-controlled weathering observed on a blockfield in Dronning Maud Land, AnGeografiskaAnnaler: Series A, Physical Geography, 95, 305-313, doi: 10.1111/geoa.12025Hedding, D.W. and Sumner, P.D. 2013. Diagnostic criteria for pronival ramparts: site,morphological and sedimentological characteristics. Geografiska Annaler: Series A, PhysicalGeography, 95, 315-322. doi: 10.1111/geoa.12021Henschel, J.R. and Lancaster, N. 2013. Gobabeb - 50 years of Namib Desert research. Journal ofArid Environments, 93, 1–6.Holmes P.J. and Meadows M.E. 2012. Southern African Geomorphology; Recent Trends andNew Directions. Sun, Bloemfontein.Le Roux, J.J. and Sumner, P.D. 2013. Water erosion risk assessment in South Africa: a proposedmethodological framework. Geografiska Annaler: Series A, Physical Geography, 95, 323-336, doi: 10.1111/geoa.12018Loubser, M.J. 2013. Wetting and drying weathering of basalt and sandstone: a process isolationstudy. Geografiska Annaler: Series A,Physical Geography, 95, 295-304, doi:10.1111/geoa.120235Moon, B.P. and Dardis, G.F. 1988. The Geomorphology of Southern Africa. Southern,Johannesburg.Nel, W., Anderson, R.L., Sumner, P.D., Boojhawon, R., Rughooputh, S.D.D.V. and Dunputh,B.H.J., 2013. Temporal sensitivity analysis of erosivity estimations in a high rainfall tropicalisland environment. Geografiska Annaler: Series A,Physical Geography, 95, 337-343 ,doi:10.1111/geoa.12017Reinwarth, B., Franz, S., Baade, J., Haberzettl, T., Kasper, T., Daut, G., Helmschrot, J., Kirsten,K. L., Quick, L. J., Meadows, M. E. and Mäusbacher, R. 2013. A 700-year record on theeffects of climate and human impact on the southern Cape coast inferred from lakesediments of Eilandvlei, Wilderness Embayment, South Africa. Geografiska Annaler: SeriesA, Physical Geography, 95, 345-360, doi: 10.1111/geoa.12015

Southern African geomorphology : looking back, moving forward

https://repository.up.ac.za/bitstream/2263/37179/1/Sumner_Southern_2013.pdf

Southern African geomorphology : looking back, moving forward

Abstract

Similar works

Full text

Available Versions

UPSpace at the University of Pretoria