Rural women and technology in South Africa: Case studies from KwaZulu-Natal Province

This article contributes to a greater understanding of the linkages between women's roles, responsibilities and their use of technology in poor rural communities. The ways in which poor rural women conceptualize technology is examined. Furthermore, how they use their knowledge and skills to develop, modify and adapt the techniques and technical processes in which they are involved are also explored. Additionally, the links between indigenous and modern technologies in relation to gender considerations in poor rural contexts are examined. This article draws from findings of primary research undertaken in two marginalized rural communities in Kwazulu-Natal, South Africa. The study reveals that the use of technologies are highly gendered and differentiated among women. Poor rural women utilize a range of technologies in both productive and reproductive activities which are central to their livelihood strategies, especially at the household level. Furthermore, although women are adapting and innovating technologies their expertise remains largely unrecognized. A range of problems and constraints exist which limit women's access to and use of technologies. A key tension identified in the study is that between the use of locally-based, indigenous technologies and modern, external technologies. This revised version was published online in July 2006 with corrections to the Cover Date.     

The West Waterberg tonstein,South Africa

What is thought to be the first recorded occurrence of a tonstein in the coalfields of South Africa is described from the Volkrust Shale Formation of the Permain Karoo Sequence in the West Waterberg Coalfield. Now, virtually pure kaolin, petrological, mineralogical and geochemical evidence points to its origin being an airfall tuff of acid composition. The concentrations of Ba, Sr, and Pb in the tonstein are unusually high. It is thought the elements were released from the ash and precipitated as phosphates of mixed composition. The phosphate distribution is not uniform and is apparently related to the fragmental texture of the rock.     

Crustal lineaments and shear zones in Africa: Their relationship to plate movements

Many of the major lineaments in southern Africa are major ductile shear zones with large displacement, occurring within, though often bounding orogenic belts. An example is the boundary to the Limpopo belt in Botswana and Zimbabwe. However, some of these shear zones only record slight displacement when considered on a crustal scale; they are merely planes recording differential movement on much larger, flat to gently dipping, shear zones where the boundary to the orogenic belt is a low-angle thrust zone. These different types of shear zones are clearly shown in the Pan-African belt of Zambia where large ENE-trending lineaments have been recorded. Recent work has shown the northern group of shears to be large lateral ramps; for example, the rocks of the copper belt are part of an ENE-verging thrust package, the southern boundary of which is a major, oblique to lateral ramp. In southern Zambia shears are more analogous to major transform faults; they form as tear faults separating zones of different thrust vergence. A possible plate tectonic model is given for this part of Africa, showing the different relative plate movement vectors estimated from the geometry of the Pan-African shear zones.     

Study on the relationship between lineaments and borehole specific capacity in a fractured and karstified limestone area in Vietnam

For a karstified limestone area in NW Vietnam, the relationship between the distribution of lineaments and borehole specific capacity is determined, resulting in the conclusion that not only the borehole geomorphological-hydrogeological position but also the lineament distribution influences the specific capacity.No significant spatial well yield patterns are evident in this highly fractured-karstified region. The supposition is that lineaments caused by geotectonic activities affect the local variability in borehole specific capacity. Sixteen pumping tests in conjunction with a comprehensive lineament analysis are used to prove this relationship. The boreholes and lineaments are classified into two groups according to their similarity in geomorphological-hydrogeological features. Lineaments tend to be less detectable in discharge areas (lowland, wide and flat valleys) in contrast to the high density in recharge areas (highland narrow-mountainous ravines). In addition, the presence of a stream network in the former can act as a recharge source to the underlain karstic groundwater system. Consequently, boreholes that are in the discharge areas with a lower density of lineaments often produce high yield. For recharge areas with a high density of lineaments, a good correlation is found between lineament density and borehole specific capacity.

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Resumen El resultado ha sido la conclusión de que tanto la distribución de lineamientos como el nivel base local de erosión, i. e. la red de arroyos, influyen el rendimiento de los pozos. No hay ningún patrón evidente significativo de rendimiento de pozos según parámetros espaciales en esta región altamente karstificada y fracturada. La suposición es que los lineamientos causados por actividad geotectónica afectan la variabilidad local de rendimiento de los pozos. Se han utilizado dieciséis pruebas de bombeo en conjunción con un análisis de lineamientos amplio para descubrir la relación. Los pozos y lineamientos se han clasificado en dos grupos de acuerdo con sus similitudes en rasgos geomorfológicos-hidrogeológicos. Se tiende a detectar menos lineamientos en valles anchos y planos en contraste con la alta densidad en áreas de valles montaosos angostos. Adicionalmente, la presencia de una red de arroyos en estos últimos puede actuar como fuente de recarga del sistema de aguas subterráneas kárstico subyacente. En consecuencia, los pozos que se encuentran en el área con una menor densidad de lineamientos pero cercanos a un nivel local base de erosión frecuentemente tienen un rendimiento alto. En el caso de los valles angostos con una alta densidad de lineamientos, se ha encontrado una correlación alta entre densidad de lineamientos y rendimiento de pozos.

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Résumé La relation entre la distribution des linéaments et le rendement des puits est déterminée pour une région dans le nord ouest du Vietnam composée de calcaires karstiques. La conclusion qui résulte de lanalyse de cette relation est que la distribution des linéaments ainsi que leur niveau local dérosion affectent le rendement des puits. Aucune tendance na été observée dans la distribution spatiale des puits selon leur rendement au sein de cette région karstique grandement fracturée. On suppose que les linéaments produits par lactivité géotectonique ont une influence sur la variabilité locale du rendement des puits. Les résultats de seize essais de pompage et une analyse complète des linéaments sont utilisés pour établir la relation. Les puits et les linéaments sont classés en deux groupes selon la similarité de leur caractéristiques géomorphologiques et hydrogéologiques. Les linéaments sont plus difficilement repérables dans les grandes vallées plates que dans les étroites vallées de montagne, qui présentent une densité élevée de linéaments. De plus, la présence de rivières dans les premières peut contribuer à la recharge du système découlement souterrain karstique sous-jacent. Par conséquent, les puits situés dans les régions à faible densité en linéaments, mais qui se trouvent près de linéaments à niveau local dérosion élevé présentent souvent un rendement élevé. Dans les vallées étroites ayant une grande densité de linéaments, il y a généralement une corrélation élevée entre la densité des linéaments et le rendement des puits.

     

Late-Precambrian correlation and the relationship between the Damara and Nama Systems of South West Africa

Recent findings about the late-Precambrian stratigraphic succession in the areas between the Orange River and the Klinghardt Mountains and south of Windhoek throw new light on the relationship between the Damara and Nama Systems.In the Orange River area the formations of the Gariep Group are unconformably or pseudo-conformably overlain by the Nama System. In central and northern South West Africa a similar relationship is exhibited by the Nosib Group and overlying Damara System.Pronounced similarities between the sedimentation and deformational history of both Nosib and Gariep indicate a probable correlation of the two groups and this result is also supported by radiometric ages.It follows that Damara and Nama are most likely either completely or partly coeval. The latter may represent a shelf facies of the former geosynclinal succession.The Gariep and Nosib deformation apparently started with the subsidence of their respective troughs and may have lasted from approximately 850 m. y. to 600 m. y. This tectonic event is older than the Damara Orogeny (550 to 450 m. y.) and may be time-equivalent to the Katanga Episode.Two late-Precambrian glaciations were widespread in South West Africa and their sedimentary deposits are important for the correlation of Gariep/Nama with Nosib/Damara.

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Zusammenfassung Neue Ergebnisse über die spätpräkambrische Gesteinsabfolge im Gebiet des Orange-Flusses und im Rehoboth-Distrikt südlich von Windhoek sind von großer Bedeutung für das Altersverhältnis zwischen Damara- und Nama-System.Im Orange-Gebiet werden die Formationen der Gariep-Gruppe diskordant oder pseudo-konkordant vom Nama-System überlagert, während in Zentral- und Nord-Südwest-Afrika das Damara-System ebenfalls diskordant oder pseudokonkordant auf die Nosib-Gruppe folgt. Sedimentations- und deformationsgeschichtliche Ähnlichkeiten deuten auf eine Korrelation zwischen Nosib und Gariep hin, und diese Interpretation wird durch radiometrische Altersbestimmungen unterstützt. Daraus folgt, daß Damara und Nama wahrscheinlich einander entsprechen, wobei die Nama-Sedimente als Plattform-Fazies der geosynklinalen Damara-Serien anzusehen sind.Die Gariep-Deformation begann schon mit dem Einsinken des Gariep-Ablagerungstroges und dürfte von ca 850-600 M. J. angedauert haben, wobei es stellenweise zur Granitisation geeigneter Sedimente und Laven kam. Diese Orogenese ist älter als die von ca. 550-450 M. J. dauernde Damara-Phase und scheint zeitlich der auch im Kaokoveld nachgewiesenen Katanga-Episode zu entsprechen.Zwei spätpräkambrische Vereisungsperioden sind weit verbreitet in Südwest-Afrika, und ihre Glazialablagerungen sind ein wichtiges Hilfsmittel für die Korrelation der Gariep-Nama-Abfolge mit der Nosib-Damara-Stratigraphie.

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Résumé De nouveaux résultats concernant la série de roches du Précambrien récent de la région de l'Orange et du district de Rehoboth au sud de Windhoek se sont révélés de haute importance pour l'étude de relation d'âge entre les systèmes Damara et Nama.Dans la région de l'Orange, le système Nama repose de façon discordante ou pseudo-concordante sur les formations du groupe Gariep; de même, en Afrique Sud-Ouest, centrale et le système Damara prend une position analogue par rapport au groupe Nosib. Des analogies dans l'histoire de la sédimentation et de la déformation permettent de réaliser une corrélation entre le Nosib et le Garieb; des déterminations de l'âge par méthodes radio-électriques appuient cette interprétation. Par conséquent, le Damara et la Nama sont vraisemblablement en rapport de conformité et les sédiments du Nama sont à considérer comme les faciès des séries géosynclinales du Damara.La déformation du groupe Gariep commença déjà avec l'affaissement des auges de dépôt et a probablement duré de 850-600 m. a.; à cette occasion se produisit, par endroit, la granitisation des sédiments et des laves appropriés. Cette orogénèse est plus ancienne que la phase du Damara qui dura de 550-450 m. a. et semble correspondre dans le temps à l'épisode Katanga également dans le Kaokoveld.Deux périodes de glaciation du précambrien récent sont très largement répandues en Afrique du Sud-Ouest et leurs dépôts glacières sont des moyens très importants pour la corrélation de la série Gariep-Nama avec la stratigraphie du Nosib-Damara.

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Damara Nama Rehoboth Windhoek. Gariep , - , , - Damara , Nosib. Nosib Gariep . , Damara Nama, , , Nama , Damara. Gariep Gariep , , 850 600 . . Damara, 550-450 , , , Katanga, Kaokoveld. - Gariep-Nama — Nosib-Damara.

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Expanded and slightly modified English version of a paper read for the author by Prof. H.Martin at the 61st Annual Congress of the Geologische Vereinigung and entitled: Spätpräkambrische Orogenesen und das Verhältnis zwischen Damara und Nama System in Südwest Afrika.     

Karibibite,a new FeAs mineral from South West Africa

Karibibite (ideally, Fe₂As₄O₉) occurs in vugs in massive loellingite of the Karibib pegmatite area, South West Africa. It is brownish yellow and finely fibrous. The thickness of the soft, single fibers is less than 1 micron, unsuitable for single-crystal X-ray study. Electron diffraction and X-ray powder pattern indicate that the mineral is orthorhombic, with $\text{a}{}_0\text{= 27.91}\text{A}\text{?}\text{, b}{}_0\text{= 6.53}\text{A}\text{?}\text{and c}{}_0\text{(}\text{fiber axis}\text{) = 7.20}\text{A}\text{?}$. The space group cannot be given. The mineral is paramagnetic with yellow fluorescence and is pleochroic with γ > 2.10, α = 1.96, 2V_α large, d = 4.07. It is soluble in acids and alkali hydroxide. Decomposition starts around 320 °C. The infra-red absorption spectrum indicates absence of AsO₄ groups. The mineral is classified tentatively as an oxide or arsenite.     

Evaluation of geologic and geomorphologic influences on borehole productivity in crystalline bedrock aquifers of Limpopo Province, South Africa

Geologically complex crystalline aquifers underlie large parts of the semi-arid Limpopo Province where some of the greatest groundwater needs in South Africa occur. It is important to identify potentially high-yielding zones that can be targeted for water supply. The study covered four distinct geologic and morpho-structural domains within Limpopo Province, together covering about 23,500?km². Results from over 2,500 pumping test analyses indicate that bedrock type (e.g. pegmatite), lithological setting (e.g. aureole of granitoids), proximity and orientation of dykes and lineaments, topographic setting (e.g. slopes or valleys) and proximity of surface-water drainages may exert an influence on borehole productivity. No correlation between borehole productivity and weathering depth was found. Lineaments and dykes striking perpendicular to the current maximum horizontal stress seem to be more favourable targets, which is inconsistent with the predicted regime. Due to the complex geologic history, it is difficult to link open discontinuities to a distinct recent or past tectonic event. Regional stress-field data, as in this case, may not account for local, possibly highly significant, stress-field variations. The hydrogeologic importance of several factors related to groundwater occurrence, here presented, can be used as a working reference for future groundwater development programmes.     

花岗岩演化与铀钍元素富集的关系:以粤北贵东岩体为例

对粤北贵东岩体铀钍丰度变化特征的研究表明,原地重熔过程导致铀钍元素向花岗岩体的上方汇聚富集,并造成铀、钍元素在空间上的分离,即在花岗岩体中,铀的丰度带位处钍丰度带之上。陆壳多次原地熔融(重熔)不但导致复式花岗岩体形成,同时造成铀元素在晚期岩体中的富集。贵东岩体内燕山早期岩体铀钍含量的东西差异被认为与卷入熔融的铀源层(寒武-震旦系)的初始埋深有关,而复式岩体铀含量的南北差异,则被解释为与晚期重熔界面倾斜方向所导致的晚期岩体的剥蚀深度有关。高铀含量和高铀钍比值并存往往是晚期岩体埋深较浅的表现,对于深部隐伏矿床的寻找有重要指示作用。     

Primary anhydrite in Precambrian gneisses from the swakopmund district,South West Africa

Anhydrite occurs as a primary rock-forming mineral in late-Precambrian gneisses from the Rössing area, South West Africa. Studies on critical mineral associations in the area indicate that temperatures during metamorphism approached or exceeded 700° C. Textural relations in the anhydrite-bearing gneisses show that the mineral remained in equilibrium with its associated phases during metamorphism.     

Granite intruding into Granodiorite: An example from the Damara Belt,South West Africa

Until now (Smith, 1965) it was thought that in the central Damara Belt, South West Africa, the Red Granite and the Salem Granodiorite are two magmatic bodies separated by (essentially) marbles. Three places were discovered, where the marbles are missing; in all three places the Red Granite intrudes the Salem Granodiorite. Experimental melting done with samples from two of these localities allows to appraise the likely conditions during the intrusion of the Red Granite (680° C, 4 kb H₂O-pressure).The White Granites — until now thought to be late or post kinematic — are a geologically heterogeneous group, at least in one place such an intrusion precedes that of the Red Granite.

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Zusammenfassung Bis jetzt dachte man (Smith, 1965) daß im Zentralbereich des Damara-Orogens, Südwest Afrika, der Rote Granit und der Salem Granodiorit zwei magmatische Körper wären, die überall von (im wesentlichen) Marmoren getrennt seien. Es wurden drei Gegenden entdeckt, an denen die Marmore fehlen; an allen drei Stellen intrudiert der Rote Granit in den Salem Granodiorit. Schmelz-Experimente mit Proben von zwei dieser Lokalitäten erlauben die Bedingungen abzuschätzen, die während der Intrusion des Roten Granites geherrscht haben (680° C, 4 kb H₂O-Druck).Die Weißen Granite — von denen man bis jetzt glaubte, sie seien spät-oder nachkinematisch — sind eine geologisch heterogene Gruppe. Mindestens an einer Stelle geht eine Intrusion der Weißen Granite derjenigen der Roten Granite voraus.

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Résumé Jusqu'à présent (Smith, 1965) on a pensé que dans la zone centrale de l'orogène de Damara (Sud-Ouest Africain) le Granite Rouge et la Granodiorite de Salem étaient deux plutonites séparées partout par des couches de marbres. On a découvert trois endroits où les marbres n'existent pas et où le Granite Rouge forme des intrusions recoupant la Granodiorite de Salem.Des essais de fusibilité sur des échantillons provenant de deux de ces localité permettent d'estimer les conditions d'intrusion du Granite Rouge (680° C avec des pressions H₂O de 4–5 kb).Les Granites blancs (acceptés jusqu'à présent comme tardi orogéniques) forment géologiquement une groupe hétérogène. En un endroit au moins, une intrusion de Granite blanc est recoupée par une intrusion du Granite Rouge, plus jeune.

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(SMITH, 1965), , , - , , . 3 , , . , , , (680° C, 4 ). , , -, , . , - , .

     

Aeromagnetic study of buried basement structures and lineaments of Sahel region (Eastern Tunisia,North Africa)

This study presents original results regarding the use of aeromagnetic to explore deep subsurface structuring in southern part of Tunisian Sahel petroleum province (Eastern Tunisia, North Africa). Several filters and techniques were applied to the total magnetic intensity (TMI) grid. First, an adequate reduce to the pole (RTP) grid was generated. The RTP map shows 17 positive and negative anomalies associated with short- and long-wavelength amplitude anomalies. Positive anomalies correspond to high magnetic basement structures estimated from seismic lines in the area. Circular anomalies are also distinguished locally and can be explained by Cretaceous magmatic rocks recognized in numerous petroleum wells. Second, specific qualitative and quantitative filters (e.g., residual-regional separation, horizontal tilt angle (TDX), tilt angle (TILT), total horizontal derivative of tilt angle (THDTILT)) were applied to elucidate the form and the extent of buried magnetic anomalies and lineaments. The resulting deep structural map revealed the presence of NW-SE, N-S, and E-W regional magnetic basement structures and lineaments and a regional tectonic node surrounding Henchir Keskes-Agareb-Mahres-Hachichina area. Two magnetic inversion models calculated across the study area highlight west to east crustal thinning trend and permit depth to basement estimation. These results are valuable for future conventional and unconventional petroleum exploration in this underexplored southern part of Sahel plain.     

The relationship between the lineaments and tectonics of the Kandalaksha Gulf in the White Sea

The regularities of the evolution of the lineaments and weakened zones within the water area and coasts of the Kandalaksha Gulf are considered. Morphostructural analysis of the territory is made and the radial diagrams of lineaments in different parts of the study area are compared. An attempt to connect the structure of the lineament system in the study area with the tectonic evolution of the major regional structure, viz., the Kandalaksha Gulf, is made.     

The alleged kimberlite-carbonatite relationship: evidence from ilmenite and spinel from Premier and Wesselton mines and the Benfontein sill,South Africa

Carbonate-rich, SiO₂-poor residua are developed in some kimberlites solidifying as ocelli, layers, or discrete dikes which satisfy petrographic definitions of carbonatite. Arguments that these rocks have mineralogies, antecedents, and comagmatic rocks differing from those of the carbonatites in alkaline rock complexes, including the specific observation that kimberlites and carbonatites contain ilmenites and spinels of different composition, have been used to refute the alleged kimberlite-carbonatite relationship. New microprobe analyses of ilmenites and spinels from carbonate-rich rocks associated with kimberlites in three South African localities correspond to spinels and ilmenites of carbonatites from alkalic complexes, or have characteristics intermediate between those of carbonatites and kimberlites. The ilmenites are distinguished from kimberlite ilmenites by higher MnO, FeTiO₃, and Nb₂O₅, and by negligible Cr₂O₃. The spinels are distinguished from kimberlite spinels by their Al₂O₃ and Cr₂O₃ contents. There is clearly a genetic relationship between the kimberlites and the carbonate-rich rocks, despite the observation that their ilmenites and spinels are distinctly different, which indicates that the same observation is not a valid argument against a petrogenetic relationship between kimberlites and carbonatites. These rocks are among the diverse products from mantle processes influenced by CO₂, and we believe that the petrogenetic links among them are forged in the upper mantle. We see insufficient justification to deny the name carbonatite to carbonate-rich rocks associated with kimberlites if they satisfy the petrographic definition in terms of major mineralogy.     

Regolith mass balance inferred from combined mineralogical, geochemical and geophysical studies: Mule Hole gneissic watershed, South India

The aim of this study is to propose a method to assess the long-term chemical weathering mass balance for a regolith developed on a heterogeneous silicate substratum at the small experimental watershed scale by adopting a combined approach of geophysics, geochemistry and mineralogy. We initiated in 2003 a study of the steep climatic gradient and associated geomorphologic features of the edge of the rifted continental passive margin of the Karnataka Plateau, Peninsular India. In the transition sub-humid zone of this climatic gradient we have studied the pristine forested small watershed of Mule Hole (4.3 km²) mainly developed on gneissic substratum. Mineralogical, geochemical and geophysical investigations were carried out (i) in characteristic red soil profiles and (ii) in boreholes up to 60 m deep in order to take into account the effect of the weathering mantle roots. In addition, 12 Electrical Resistivity Tomography profiles (ERT), with an investigation depth of 30 m, were generated at the watershed scale to spatially characterize the information gathered in boreholes and soil profiles. The location of the ERT profiles is based on a previous electromagnetic survey, with an investigation depth of about 6 m. The soil cover thickness was inferred from the electromagnetic survey combined with a geological/pedological survey.Taking into account the parent rock heterogeneity, the degree of weathering of each of the regolith samples has been defined using both the mineralogical composition and the geochemical indices (Loss on Ignition, Weathering Index of Parker, Chemical Index of Alteration). Comparing these indices with electrical resistivity logs, it has been found that a value of 400 Ohm m delineates clearly the parent rocks and the weathered materials. Then the 12 inverted ERT profiles were constrained with this value after verifying the uncertainty due to the inversion procedure. Synthetic models based on the field data were used for this purpose. The estimated average regolith thickness at the watershed scale is 17.2 m, including 15.2 m of saprolite and 2 m of soil cover.Finally, using these estimations of the thicknesses, the long-term mass balance is calculated for the average gneiss-derived saprolite and red soil. In the saprolite, the open-system mass-transport function τ indicates that all the major elements except Ca are depleted. The chlorite and biotite crystals, the chief sources for Mg (95%), Fe (84%), Mn (86%) and K (57%, biotite only), are the first to undergo weathering and the oligoclase crystals are relatively intact within the saprolite with a loss of only 18%. The Ca accumulation can be attributed to the precipitation of CaCO₃ from the percolating solution due to the current and/or the paleoclimatic conditions. Overall, the most important losses occur for Si, Mg and Na with −286 × 10⁶ mol/ha (62% of the total mass loss), −67 × 10⁶ mol/ha (15% of the total mass loss) and −39 × 10⁶ mol/ha (9% of the total mass loss), respectively. Al, Fe and K account for 7%, 4% and 3% of the total mass loss, respectively. In the red soil profiles, the open-system mass-transport functions point out that all major elements except Mn are depleted. Most of the oligoclase crystals have broken down with a loss of 90%. The most important losses occur for Si, Na and Mg with −55 × 10⁶ mol/ha (47% of the total mass loss), −22 × 10⁶ mol/ha (19% of the total mass loss) and −16 × 10⁶ mol/ha (14% of the total mass loss), respectively. Ca, Al, K and Fe account for 8%, 6%, 4% and 2% of the total mass loss, respectively.Overall these findings confirm the immaturity of the saprolite at the watershed scale. The soil profiles are more evolved than saprolite but still contain primary minerals that can further undergo weathering and hence consume atmospheric CO₂.     

The co-production of livelihoods and land use change: Case studies from South Africa and Ghana

Land use change and livelihood systems are often analyzed separately or with one “driving” the other. This “driver-feedback” relationship has been buttressed by approaches to social process that are often far too static. Actors are confronted with a bundle of choices that they must negotiate as they create pathways of change. These choices are always bound up in relations of power and the knowledges that are the conditions for and results of these relations. We suggest that land uses and livelihood are different manifestations of the social processes by which individuals and groups negotiate the everyday conditions that shape their lives. We propose a framework that extends current understandings of the relationship between land use change and livelihoods by treating social relations of power as the entry point into this complex relationship. We underpin our arguments with empirical examples from South Africa and Ghana that locate power/knowledge relations in the context of social change in both study areas.     

The Effectiveness of Centre-Pivot Irrigation from Dolomitic Ground Water in the Northwest Province,South Africa

Because South Africa is situated in a semi-dry region, the limited water resources are placed under increasing pressure by consumers from different sectors. Irrigation consumes more than half of the available water resources in South Africa. In the Northwest Province large volumes of water are found in dolomitic aquifers. Since 1970 irrigation from these aquifers has resulted in an exponential growth in the withdrawal of groundwater. The purpose of this study is to evaluate the effectiveness of groundwater utilization with centre-pivot irrigation in the Northwest Province, as well as to identify the most important variables that influence this effectiveness. Factor Analysis and Multiple Regression Analysis were used to establish a model with which the probable effectiveness of groundwater utilization on a specific farm can be predicted. The results show that four variables have a significant effect on the net profit margin from centre-pivot irrigation in the study area, namely: • Knowledge regarding the water capacity of the soil • Adjusting irrigation according to precipitation • The use of a yield target for fertiliser application, and • Soil characteristics The above parameters were used to develop a model with which farmers in the study area can be ranked according to the effectiveness of their water usage for centre-pivot irrigation. This revised version was published online in July 2006 with corrections to the Cover Date.     

The transfer of agricultural technology and the development of small-scale farming in rural Africa: Case studies from Ghana, Sudan, Uganda, Zambia and South Africa

In many developing countries, research institutions or centres have been established to develop and/or adapt technologies that would help agricultural development. This is particularly true in Africa where national efforts have been supplemented with international research institutes. Although some modest progress has been achieved in improving agricultural technology, on the whole, the improvement record is not quite encouraging among the small-scale farmers. In many areas, either there are no improved technologies, or where they exist, are unacceptable by farmers. However, where useful technologies exist, their spread has been very limited and where they have been adapted, the benefits only accrue to a small segment of the community. The logical question posed is: why and how do we find ourselves in the current situation? This paper considers the view that to understand fully why the available technologies have remained largely at the research centres, there is need to examine the whole process of research, development, dissemination and utilization of agricultural technology. It is significant to investigate the structural constraints and prospects under which those involved in the process work, their motivations and the interactions between different groups. The traditional ‘top-down’ of development strategy should be supplemented with farmers' indigenous knowledge, and programmes encouraging transfer of agricultural technology should include institutional support. Only by the identification of farmers' environmental and resource utilisation, preferences, socio-economic circumstances and constraints can a development programme of optimum meaning to farmers be devised and implemented with success.     

New primary vanadium-, germanium-, gallium-, and tin-minerals from the Pb-Zn-Cu-deposit Tsumeb,South West Africa

Six unknown mineral species and subspecies are described. They were discovered in and nearby the Tsumeb main orebody and investigated under the ore microscope. Microprobe analysis revealed the presence of new mineral compounds with the paired elements: vanadium and gallium, vanadium and germanium, and tin and germanium, all of them sulfides. By means of diagrams their positions and their relations to minerals of known composition are shown and discussed.

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Zusammenfassung Es werden sechs unbekannte Mineralspezies und Subspezies beschrieben. Sie stammen aus dem Tsumeber Haupterzkörper und nahebei gelegenen Erzprospekten und wurden unter dem Erzmikroskop untersucht. Durch Untersuchung mit der Elektronen-Mikrosonde wurde das Vorhandensein neuer Mineralverbindungen nachgewiesen mit den Elementenpaaren: Vanadium und Gallium, Vanadium und Germanium und Zinn und Germanium sämtlich Sulfide. An Hand von Dreistoff-Diagrammen werden ihre Stellung und ihre Beziehungen zu Mineralien bekannter Art aufgezeigt und diskutiert.

     

Capital on the move: The changing relation between livestock and labor in Mali, West Africa

In dryland areas of the Africa, livestock play important economic roles as commodities, wealth stores, producers of products, and agents of environmental change. Conventional depictions of livestock economies in this region have focused (in support or against) on the need for greater engagement of livestock producers with markets supplying meat to urban areas. This paper argues this singular focus has led analysts to ignore two important aspects of livestock economies: livestock as a preferred store of wealth across a wide range of social groups and the need for specialized labor to manage these livestock across open pastures to maintain their productivity and limit their negative environmental impacts. In the West African Sahel, the capital-like nature of livestock wealth has become more clear with a growing fraction of the region’s livestock owned by investors with little connection to livestock husbandry. Livestock investments are maintained on a day-to-day basis by hired herders who facilitate access to ephemeral pastures and water. A particular concern is the changing geographies of livestock ownership and the herding labor in relationship to regional pastures (to economic and environmental ends). This relationship will be explored using the case study of the Maasina region of central Mali - a historically important livestock region, which is now undergoing significant labor emigration. Building from a long-term ethnographic engagement with local livestock owners and herders, the results of ownership surveys of livestock herds across a 14-year period and interviews of urban-based emigrants from the study area about investment decisions will be used to analyze the changing geographies of livestock investment and herding labor in the Maasina.