East Griqualand Research Articles

Historical mammal incidence in the Cape Province vol. 2: The eastern half of the Cape Province, including the Ciskei, Transkei and East Griqualand, by C.J. Skead

Historical mammal incidence in the Cape Province vol. 2: The eastern half of the Cape Province, including the Ciskei, Transkei and East Griqualand, by C.J. Skead

The origin of Patagonia revealed by Re-Os systematics of mantle xenoliths

We present mineral chemistry and whole rock major, trace, and platinum group element (PGE) concentrations, and Re-Os isotope data for eighteen mantle xenoliths carried to the surface of southern Patagonia (45°–52°S) by Paleocene to Pleistocene alkaline basalts in seven localities scattered widely across southern South America. The new data along with those previously published show that peridotites derived from the lithospheric mantle of the Deseado Massif (DM), southern Patagonia, have compositions indicative of higher degrees of partial melt extraction compared to those from surrounding regions. Re-depletion model ages (TRD) of mantle xenoliths from the DM (n=20) range from 0.5 to 2.1Ga, with an average of 1.5Ga. In contrast, samples from the surrounding areas (n=39) have a wider range of Re-depletion ages from 0.0 to 2.5Ga, with an average of 1.0Ga. Similar geochemical characteristics are recognized between the lithospheric mantle section of the DM and that beneath East Griqualand (∼1.1Ga), south-eastern Africa, which is related to the Proterozoic Namaqua-Natal Province. The Re-Os systematics of the mantle xenoliths are indicative of Meso to Paleoproterozoic ages for partial melting and stabilization processes of the lithospheric mantle of southern Patagonia, which are considerably older than the crystallization ages obtained for the scarce basement rocks of Patagonia (<0.6Ga). In addition, published elastic thickness (Te) estimates of southern South America show maximum values on the submerged continental region located between the DM and the Malvinas/Falkland Islands, where Grenville-age metamorphic rocks are exposed. These geochemical and geophysical results suggest that southern Patagonia and the Malvinas/Falkland Islands and plateau constitute an integrated and relatively rigid continental block formed mainly during the Meso to Paleoproterozoic as part of the supercontinent Rodinia.To the north, the formation of the North Patagonian Massif (NPM) seems to be contemporaneous with that of the DM. Nevertheless, its ancient lithospheric mantle and lower crust appear to have been widely eroded and replaced by relatively young convecting mantle, possibly during the Carboniferous collision between the DM and the NPM. The differences between the DM and NPM lithosphere histories apparently controlled the subsequent formation and distribution of Jurassic epithermal Au-Ag deposits.

Age, Composition and Thermal Characteristics of South African Off-Craton Mantle Lithosphere: Evidence for a Multi-Stage History

A mineral chemistry and whole-rock major element, platinum group element (PGE), and Re–Os isotope dataset is presented for a large suite of mantle xenoliths from 13 kimberlites that erupted through the Proterozoic mobile belts surrounding the Archean Kaapvaal craton of South Africa. The peridotites have compositions that are unusually infertile compared with post-Archean lithosphere outside southern Africa (e.g. mean olivine Mg-number = 91·4; mean whole-rock Al2O3 = 1·3 wt %) but are similar to xenoliths from the Gibeon kimberlites of southern Namibia, which also erupted through Proterozoic lithosphere. Rhenium depletion model ages (TRD) determined from 58 Os isotope compositions of peridotites span a range from 2·6 to 0·6 Ga, with an average of 1·67 Ga. Latest Archean TRD model ages were determined for three samples from different localities, but whether these indicate the off-craton presence of reworked Archean lithosphere or are simply artifacts of heterogeneity in the convecting mantle is unclear. Low and relatively restricted Al2O3 contents combined with variable 187Os/188Osi in the peridotites are most consistent with a two-stage melt extraction history for southern African off-craton lithosphere, with initial formation in the earliest Proterozoic by widely varying (but, on average, moderate) degrees of melting, followed by a second melt extraction episode associated with the Namaquan orogeny at 1·3–1·0 Ga. Extensive metasomatism in the lithosphere beneath East Griqualand, SE of the craton, resulted in extreme clinopyroxene enrichment and addition of ilmenite along with disturbance of PGE abundances in many samples. This is probably due to percolation of melts similar to those parental to the Cr-poor megacryst suite, and related pyroxenites, which are abundant in East Griqualand kimberlites. In other regions, there is evidence for less extensive clinopyroxene addition and cryptic metasomatism. Southern African off-craton mantle xenoliths record evidence of a Mesozoic heating episode probably brought about by mantle upwelling linked to continental break-up and/or Karoo flood basalt magmatism. Prior to this, the thermal state, and hence the thickness, of southern African off-craton and cratonic lithosphere were probably roughly similar. The mantle upwelling responsible for lithospheric heating also appears to have caused moderate (≈30 km) thermal erosion of the off-craton portions of the southern African lithosphere.

Factors influencing the long-term competitiveness of commercial milk producers: evidence from panel data in East Griqualand, South Africa

This study investigates factors influencing the long-term competitiveness of 11 commercial milk producers from East Griqualand (EG), South Africa using unbalanced panel data for the period 1990 to 2006. Results of a ridge regression analysis show that dairy herd size, the level of farm debt, annual production per cow, technology and policy changes over time, and the ratio of trading income to total milk income influence the long-term competitiveness of these milk producers. To enhance their competitiveness in a deregulated dairy market, relatively small and profitable EG milk producers should consider increasing their herd sizes, as the importance of herd size in explaining competitiveness suggests that size economies exist. All EG milk producers should consider utilising more pasture- and forage-based production systems to lower feed costs and select dairy cattle of superior genetic merit to improve milk yields on pasture.

Impact of market deregulation on the competitiveness of commercial milk producers in East Griqualand: a unit cost ratio (UCR) analysis: 1983–2006

This study investigates the impact of dairy market deregulation on the competitiveness of milk producers who comprise the East Griqualand (EG) study group in KwaZulu-Natal and the Eastern Cape Province of South Africa. The study uses a microeconomic approach, the unit cost ratio (UCR) method of competitiveness analysis, to assess changes in the relative competitiveness of EG milk producers from 1983–2006. Findings of previous research indicate that dairy market deregulation in the 1980s and 1990s caused lower real milk producer prices, increased uncertainty and higher exit rates in the South African dairy industry. Results of the UCR analysis suggest that EG milk producers were not competitive based on the net local price received for milk but were competitive when dairy cattle trading income was included. This suggests that dairy cattle trading income played an important role in enhancing the profitability of EG dairy enterprises in the study period. Further UCR analysis revealed that the top one-third of EG milk producers were relatively competitive from 1983–2006 due to higher real milk prices and lower unit costs. A panel data study of individual EG milk producers could be used to identify other important factors affecting milk producer competitiveness over time.

Fine-grained pyroxenites from the Gansfontein kimberlite, South Africa: Evidence for megacryst magma - mantle interaction.

The Gansfontein kimberlite contains a suite of fine-grained xenoliths dominated by orthopyroxene, and containing ilmenite, phlogopite, and occasional garnet, with minor quantities of olivine and sulphide. Lamellar intergrowths of orthopyroxene and ilmenite were observed in one sample. The fine grained orthopyroxenite assemblages were observed as discrete xenoliths, as a vein in lherzolite, and as a zoned margin surrounding a megacrystic dunite. The minerals are characterized by intra- and inter-grain chemical heterogeneity, but are on the whole compositionally similar to those in the abundant, highly evolved Cr-poor megacryst suite at Gansfontein. However, they differ to varying degrees from megacrysts in the concentration of minor elements such as Cr, Al and Ti. Mineral compositions in a pyroxenite vein in lherzolite are higher Cr and Mg#, and lower in Fe3+ than in the discrete fine-grained pyroxenites, indicating chemical interaction with peridotite. A single zircon-bearing mica-clinopyroxenite has mineral compositions similar to MARID xenoliths. Fine-grained orthopyroxenites, recognized previously from the Weltevreden and Mzongwana kimberlites and interpreted as rapidly crystallized magmas, are here suggested to result from a reaction between megacryst magma and solid mantle peridotite. Mica-clinopyroxenite may represent the liquid end-product of this reaction. Chemical and modal differences of orthopyroxenites from megacrysts result from reaction with peridotitic components, lack of buffering by typical megacryst mineral assemblages, and possibly shallower origins. Textures and fine-scale chemical disequilibrium indicate that reaction postdates some episodes of megacryst formation and was probably underway when the xenoliths were sampled by ascending kimberlite. Orthopyroxene-garnet thermobarometry indicates an origin of one Gansfontein pyroxenite at ~1215°C and ~3.3 GPa, similar to the locus of megacryst crystallization under East Griqualand. The Gansfontein pyroxenites indicate interaction of magmas at shallow levels within the subcontinental lithospheric mantle and provide evidence for melt-peridotite reaction that includes a possible reaction relationship between Ti-rich melt and olivine. Similar phase relations and processes may also play a role in megacryst petrogenesis, for which these pyroxenite xenoliths could represent a small-scale, initial stage analogue. The liquid end-products of such reaction may be important components of kimberlites and mantle metasomatic fluids.

Isolation of Haemophilus somnus from dairy cattle in kwaZulu-Natal. An emerging cause of 'dirty cow syndrome' and infertility?

Haemophilus somnus was consistently isolated from vaginal discharges of dairy cows submitted from field cases of vaginitis, cervicitis and/or metritis in the KwaZulu-Natal Midlands during the period July 1995 - December 2000 and from the East Griqualand area in November/December 2000. The purulent vaginal discharges, red granular vaginitis and cervicitis, and pain on palpation described in these cases was very similar to that reported in outbreaks of H.somnus endometritis syndrome in Australia, Europe and North America. In all the herds involved in these outbreaks, natural breeding with bulls was employed. Although there was a good cure rate in clinically-affected animals treated with tetracyclines, culling rates for chronic infertility were unacceptably high. Employment of artificial insemination in these herds improved pregnancy rates in cows that had calved previously, but many cows that had formerly been infected failed to conceive.

OPTIMUM RESOURCE ALLOCATION: ESTIMATES FOR FRESH-MILK PRODUCERS IN NATAL

ABSTRACT The allocation of some of the more important inputs in the production of fresh milk in three regions of Natal is assessed with the use of production functions. The marginal rate of substitution criteria is used to establish least cost combinations of concentrates and pastures in East Griqualand and in the Natal Midlands, and concentrates and forages in the Ixopo area. Estimates of profit-maximizing combinations of inputs are also presented for the three regions. The results indicate that fresh-milk farmers need to reassess their combinations of inputs to improve profits.

The distribution, habitat requirements and conservation status of Rudd's Lark Heteromirafra ruddi in South Africa

The past and present distributions of Rudd's lark are reviewed, and recent claims concerning range reduction examined. The species occurs within a geographically and altitudinally restricted range and conforms closely to the boundaries of a restricted group of grassland vegetation types. Its presence within these is determined by local vegetation floristics and structure, and sites with moderately or heavily grazed grassland without forb invasion are preferred. Changing land-use practices have probably adversely influenced the distribution of Rudd's lark in parts of the Transvaal, but populations were discovered in Natal and rediscovered in East Griqualand, an area where the species was thought to be extinct. Distribution in the Orange Free State is reassessed, and the western limits of the species' range are redefined.

RELATIVE ABUNDANCE OF CRANES (GRUIDAE) IN THE CAPE PROVINCE

Summary Siegfried, W. R. 1985. Relative abundance of cranes (Gruidae) in the Cape Province. Ostrich 56:101-103. The results of monthly roadside counts of Crowned Cranes Balearica regulorum, Wattled Cranes Grus carunculatas and Blue Cranes Anthropoides paradisea show that Blue and Crowned cranes occurred most abundantly and densely in the eastern part of the Cape Province in 1965–1966. The Blue Crane's average relative abundance was approximately four times that of the Crowned Crane whose population occupied tend to breed in summer, the Blue Crane slightly earlier than the Crowned Crane. The population of the Wattled Crane was a small relict, occurrin in East Griqualand. Based on a rough estimate, there were about 1000–1500 Crowned Cranes and about 7000–10000 Blue Cranes in the Cape Province in the mid-1960s.

Evaluation of veld potential in east griqualand using beef cattle under two grazing management systems

Abstract Beef production from veld, in the short term, was found to be greater under a continuous grazing system than under a rotational grazing system. Average daily gains decreased from a maximum in late‐spring and the highest three‐year mean value was 0,5 kg/animal/day. Livemass gains/ha were highest at a stocking rate of 2,2 animals/ha and were 131,4 kg/ha under continuous grazing and 88,6 kg/ha under rotational grazing. Estimated mean maximum gains/ha were 0,78 kg/ha/day at a stocking rate of 2,5 animals/ha under continuous grazing and 0,55 kg/ha/day at a stocking rate of 1,7 animals/ha under rotational grazing. However, optimum economic stocking rates were estimated to occur below those where beef production/ha was maximum.

Politics and land in Matatiele 1844–1900: A report from the archives

This essay is concerned with some of the details of the history of Matatiele District, in its wider East Griqualand context, from the mid‐nineteenth century to the 1900s. The Griqua State (capital at Kokstad) is well documented as is the general history of a South African peasantry, a topic which has also inspired a number of specific regional studies. But the polity established by Nehemiah Sekhonyana Moshesh at Matatiele has not been studied and was sufficiently important and long‐lasting to deserve some attention. Section 1 attempts to show the need to consider Lesotho's influence in the Drakensberg/Matatiele area as opposed to the more obvious Griqua connection; section 2 suggests how weak the Griqua link was in day to day practice. These case studies also provide good illustrations of a number of important themes in both colonial and South African history. Nehemiah's relationship with local and imperial authorities displays well the contrast between local ‘settler’ colonialism with its ‘white settler'...

More beef from pasture 1. Veld management for a sustained increase in meat production

A description is given of the development and application of a flexible 15-camp grazing system on a sourveld farm in East Griqualand. A high stocking density is considered fundamental in achieving good herbage utilisation and high level of production per animal and per ha. The importance of not starting grazing too early in the season is stressed. Keywords: beef production|pastures|veld management|meat production|development|grazing systems|farming|sourveld|farms|East Griqualand|stocking densities|herbage|utilisations|production|animals|carrying capacities

2. Veld reinforcement for increased meat production

Abstract A programme of radical veld improvement applied on a farm in a cool, high rainfall area of East Griqualand is described. The veld was burnt in spring and fertilized with 300 kg/ha superphosphate and 45 to 60 kg/ha N. It was then heavily grazed with cattle and sheep during summer, using an eight‐camp rotational system, and in February it was oversown with cocksfoot and given a further 45 kg/N/ha. Grazing, with cattle only, continued into autumn. In the second year clover was sod‐seeded into part of the area. With the eight‐camp grazing system, the number of MLU grazing days per ha increased from 161 on unimproved veld to 411 in the third year after improvement. In addition, the conception rate of cows increased from 85% to 97% and lambs could be run on the area which previously would support only mature, dry sheep.

THE STATUS OF THE WHISTLING DUCKS IN SOUTH AFRICA

Summary Clark, A. 1974. The status of the whistling ducks in South Africa. Ostrich 45:1-4. Since the 1920's the status of Dendrocygna viduata and D. bicolor has changed from that of an irregular to that of a regular species in the Transvaal, Zululand, Natal and Orange Free State. In more recent years their numbers have shown a steady increase and breeding has been established. D. viduata numbers built up more quickly than D. bicolor and it has become an established resident whereas D. bicolor is primarily a summer visitor. In the Western Cape Province there has been little change in the status of either species but there are indications that D. viduata is appearing mote regularly in the Eastern Cape Province. The position in East Griqualand and the Transkei is obscure. In South West Africa, excluding the north east corner, D. viduata remains irregular and D. bicolor rare. The preference shown by both species for areas where sewage effluent is disposed of and for new storage dams inevitably links their spread and increase with that of the human population.

Reactions to Rinderpest in Southern Africa 1896–97

Rinderpest, a highly contagious cattle disease which swept through southern Africa in 1896–7, has attracted little interest from historians. A more detailed consideration of its effect on a cattle-keeping peasantry within the context of an industrializing economy assists in illuminating some of the socio-economic and political forces operative in the 1890s.The spread of rinderpest was acompanied by widespread suspicion and rumour. Some Europeans thought that the disease was spread by Africans. Many Africans, for their part, were convinced that rinderpest was a product of the white man's malice. Over large areas rinderpest was accepted with an attitude of fatalism and resignation. In Basutoland and East Griqualand, however, local leaders emerged who were willing to utilize grievances and rumours stemming from rinderpest for attempts at mobilization for the wider objective of revolt.The loss of large numbers of cattle caused considerable social and economic distress in African communities. The transport system was paralysed in an economy dependent on the extensive use of the ox-wagon, and this resulted in price rises and profiteering in more remote areas. With the disappearance of the source of meat and milk Africans experienced considerable hardship and in some cases starvation. Forced into taking contingency action, activities ranged from planting vegetables to stock-thieving. Generally, however, the impoverishment of Africans caused by rinderpest contributed to the growing proletarianization of Africans and the process of labour migration. Rinderpest did not produce fundamental structural changes in Southern African society, but it did emphasize the processes which were to characterize industrial South Africa of the twentieth century.

Sea Breeze Studies In Natal

Abstract On the Natal coast maximum onshore components in .the sea breeze circulation are shown to occur below 1,000 f.t. The sea hreeze is shown on occasions to penetrate inland along a shear line for at least 40 miles and possibly even further. Characteristics of the depth, velocity and surging within this onshore air layer are examined and the relative contribution to the wind by the sea breeze circulation and by the gradient wind is discus.sed. It is suggested that on many occasions the inland penetration of the onshore wind, possibly with modified marine air properties, takes place in response to lowered pressures in adjacent inland areas in Southern Natal and East Griqualand.

The initiation of a Baca isangoma diviner

SYNOPSIS The activities and social function of the Nguni diviner (Zulu, Baca isangoma; Xhosa igqira) has been described by a number of writers, notably Hunter and Kohler. This article gives an account of an initiation ceremony observed among the Baca of the Mount Frere district, East Griqualand and, as such, fills a gap in the published data on the subject. A person is “called” to the profession by the ancestral spirits and a diviner is conceived to be in a special relationship towards them. The initiation takes place after a year's preliminary training with an established doctor, during which time the novice attends seances (iintlombe) and acquires an extensive knowledge of medicinal plants. Food and social taboos are observed and dreams play an important part in directing personal life. The initiation consists of seances, through which rapport is established with the spirits, and the ritual killing of a white goat (umthul’ entaeni) and a beast .(inkomo yokuphuma), the latter revealed to the novice in a ...

A Fishing Scene from East Griqualand

A Fishing Scene from East Griqualand

THE PETROLOGY OF THE MOUNT ARTHUR DOLERITE COMPLEX, EAST GRIQUALAND

Abstract A plug-like mass of Karroo dolerite, situate in the Mount Currie district of East Griqualand, is described in detail. By collapse of the roof, large blocks of sediments, belonging to the Stormberg series, were immersed in the magma. Three phases of igneous activity contributed to the formation of the complex. The first magma was tholeiitic, rich in iron oxides, and intruded along an outer ring-dike. Cauldron subsidence within the ring-dike led to the intrusion of a large volume of olivine-dolerite magma. The final phase consisted of a magma which was relatively poor in olivine. It is represented by a few narrow dikes and thin sheets. Interaction of the olivine-dolerite magma with the enveloped sediments produced tholeiites, in which pigeonite occurs instead of olivine.