Central Zimbabwe Research Articles

The role of ancient human settlements in creating nutrient hotspots in a savanna ecosystem, central Zimbabwe

Ancient human settlements play an important role in creating heterogeneous African savanna ecosystems through forming nutrient hotspots with increased biodiversity and improved forage quality. However, plant community development and herbivore utilization of these sites after abandonment remain poorly understood. We compared plant and soil parameters in ancient human settlements with off-sites locations. In addition, we set camera traps in ancient settlements and surrounding vegetation to determine their use by herbivores. Grass basal cover, height, biomass and species diversity in ancient settlements had recovered to similar levels with the surrounding landscape. Ancient settlements had small trees (in terms of height and canopy volume), lower tree density and lower species diversity than the surrounding landscape. Soil phosphorus and calcium were higher in ancient settlements than surrounding landscape, while pH, nitrogen, potassium, magnesium and sodium were similar between the two sites. Impala and greater kudu camera sightings were higher in ancient settlements than surrounding vegetation, while warthogs showed no preferential foraging between ancient settlements and surrounding vegetation. We conclude that ancient settlements created functional heterogeneity through altering the structure of savanna vegetation influencing foraging patterns of herbivores such as impala.

Geochemistry of extremely modified chromites from the chrysotile asbestos-bearing Zvishavane Ultramafic Complex, south central Zimbabwe

ABSTRACT The Zvishavane Ultramafic Complex (ZUC) is a metamorphosed ultramafic-mafic body exposed within the Zvishavane gneiss complex in south central Zimbabwe. The complex hosts Africa's largest mine and reserves of high-grade chrysotile asbestos. Rock types of the ZUC range from serpentinites, metadunites, and metagabbros. Accessory chromites, which are altered to ferrian chromites, are hosted in metadunites and serpentinites. Chromium number, Cr# (100*Cr/(Cr + Al)), is extremely high, and ranges from 90.6 to 99.5. Low magnesium number, Mg# 100*Mg/(Mg + Fe2+), ranges from 5.1 to 8.4. Most ZUC ferrian chromites occur as inclusions or marking the outlines of relict olivine crystals, and in veinlets traversing the serpentinites. On 100*Fe3+/(Al + Fe3+) versus 100*Fe2+/(Mg + Fe2+) diagram, the chromites all plot in the magnesioferrite field, and in the ferrian chromite field on a Fe3+-Cr-Al ternary diagram. On wt% Al2O3 versus wt% Cr2O3 and 100*Cr/(Cr + Al) versus 100*Mg/(Mg + Fe2+) plots, chromites all plot in the modified trend fields. The bulk of the chromites were metamorphosed at temperatures of ≤500°C, and no samples experienced temperatures exceeding 550°C. A plot of Fe3+/(Fe3++ Fe2+) versus wt% MnO is indicative of hydrous metamorphism of ZUC chromites. It is interpreted that extensive modification of the ZUC chromites occurred during hydrothermal alteration, under conditions more oxidising than quartz-fayalite-magnetite but less than magnetite-hematite, which accompanied the formation of high-grade chrysotile asbestos for which the ZUC is famous. Four granitic plutons exposed within 50km of ZUC were likely the source of hydrothermal fluids responsible for extensive hydrothermal alteration, which likely led to the formation of high-grade chrysotile asbestos, and almost completely modifying the chromites in the process. Compositions of accessory chromites in chrysotile asbestos meta-ultramafic bodies elsewhere are likely to be extremely modified.

Effects of Covid-19 on urban and peri-urban farmers in Central Zimbabwe

The COVID-19 pandemic has affected the global economy since its advent in 2020. The agricultural sector is among the sectors that have been significantly affected by the pandemic. The effect of the pandemic in the agriculture sector is cutting across all the value chains inclusive of production, marketing and input supply, among others. In addition, both small-scale and large-scale producers have been affected. This study looks at the effects of the COVID-19 pandemic on urban and peri-urban agriculture in Gweru, Zimbabwe with a view to derive lessons that can inform discussion on how the urban and peri-urban farmers can circumvent economic shocks such as COVID-19 in the future. Agriculture in and around urban areas is practised by a significant number of people in some continents including Africa. Urban and peri-urban agriculture has a noticeable contribution to food and nutrition security and has a potential to reduce poverty. Face -to -face interviews were conducted with a total of 40 individual farmers using a structured questionnaire and three virtual focus group discussions were held with a total of 24 farmers. Simple random sampling was used to select participants from a list of farmers provided by the Department of Agricultural Technical and Extension Services. Each member of the population had an equal chance of being selected. The study established that the pandemic has had several effects on these urban and peri-urban farmers including limited access to markets, loss of income, increased cost of farming, competition from non-traditional farmers, adoption of innovative delivery mechanisms, difficulty in accessing inputs and reduced farm labour. Farmers were forced to adopt information technology to enhance communication among themselves and other stakeholders. To protect and safeguard livelihoods within the agricultural system, the study recommends that the government increases spending on social safety nets for urban and peri-urban farmers, reform agricultural finance and improve financial support to smallholder farmers. Key words: COVID-19, Agriculture, Urban, Peri-Urban, Food Security, Information Technology, Safety Nets

Petrographic and mineral chemistry investigation of the high-grade chrysotile asbestos-bearing Zvishavane Ultramafic Complex, south central Zimbabwe

The Zvishavane Ultramafic Complex (ZUC) in the south central part of the Zimbabwe craton is comprised of coarse-grained serpentinites, metadunites and metagabbros and hosts Africa's largest reserves, and largest mine, of high-grade chrysotile asbestos. Magnesiohornblende, actinolite, plagioclase (An0.6–41.9), augite, diopside and clinozoisite constitute the mineralogy of the ZUC. Forsteritic olivine (>Fo90) was altered to form chrysotile and antigorite minerals, although some primary olivines are preserved. Contents of Al2O3 range from <1 to >2.5 wt% at TiO2 values of <0.7 wt% consistent with an island arc setting for the ZUC that originated from tholeiitic magmas. The Zvishavane Ultramafic Complex was metamorphosed at relatively high temperatures (542-779 °C) and low pressures (1.2-2kbars), consistent with contact metamorphism. Intrusion of several granitic batholiths relatively close to the ZUC likely triggered hydrothermal fluid migration which metamorphosed the ZUC. The associated asbestos deposits likely formed during hydrothermal circulation events. Zoned amphiboles, the occurrence of magnesiohornblende and actinolite, as well as cross-cutting serpentine veins are consistent with at least two stages of alteration and/or metamorphism of the ZUC. The lack of a thrust contact between the ZUC and its country rocks is consistent with the ZUC having intruded into the host Zvishavane Gneiss Complex and possibly acted as a feeder to the nearby Mberengwa greenstone belt (MGB). However, the occurrence of near end-member forsteritic olivine, the presence of zoned amphiboles, and faulting within the ZUC are all suggestive of an ophiolitic origin although forsteritic olivines also occur in intrusive layered complexes. Metamorphism of the ZUC, ascribed to intrusion of multiple batholiths and possibly the MGB, likely led to the formation of ZUC chrysotile asbestos deposits.

Challenges and Opportunities in Communicating Weather and Climate Information to Rural Farming Communities in Central Zimbabwe

Abstract Sustainability of rain-fed agriculture in semiarid regions is being threatened by climate variability and change. Weather and climate information (WCI) can be used to reduce the effects of this threat on agricultural production. WCI may be available, but is it readily accessible and communicated/disseminated efficiently to intended end users? Are stakeholders able to interpret the information to correctly inform decision-making? To answer these questions, in view of intermediate stakeholders (service providers to farmers), a study was carried out in two districts of the Midlands Province of Zimbabwe to identify the type and sources of WCI received by these stakeholders as well as constraints and opportunities to access, interpretation, and use of WCI. The study sample was drawn from the Midlands Provincial Drought Relief Committee, a link between the sources of WCI and the smallholder farmers. A questionnaire pretested for clarity and checked for internal consistency of themes using the standardized Cronbach’s alpha was used to collect data. Descriptive statistics were generated using SPSS (version 20.0). Findings were that WCI was sometimes not readily available or was received late. Approximately 36% of the intermediate stakeholders (service providers) passed on WCI to farmers in its original form, from the main source the Meteorological Services Department. It was also unfortunate to discover that 36% of the respondents had challenges interpreting WCI. Impediments to the use of WCI by farmers included scientific information not aligning with indigenous information, which is better understood by farmers, and lack of trust in WCI. It is imperative to improve access to WCI and to train stakeholders on interpretation and dissemination of WCI. Significance Statement Weather and climate information—if accurate, accessible, provided in a timely manner, and well understood—can be helpful in the farm decision-making process. Its usefulness is becoming more important with increased climatic variability and change. This paper highlights the challenges and opportunities for service providers in communicating and disseminating WCI. We believe that findings from the study will give direction to efficient utilization of the information by the various end users, for which smallholder farmers are the majority in most developing countries.

Disjunct resident population of Melodious Lark Mirafra cheniana discovered in East Africa

We describe the discovery of a previously unknown population of Melodious Lark Mirafra cheniana from northern Tanzania and southern Kenya, some 2000 km north of what was previously thought to be its northern limit in central Zimbabwe. The identification of this population as M. cheniana is based primarily on analyses of mitochondrial DNA and song. We also clarify relationships within this genus by sequencing material of White-tailed Lark Mirafra albicauda for the first time; although its relationships with other species in the group remain unclear, our analyses clearly show it to be different from M. cheniana in the newly discovered population. The discovery of a population of M. cheniana in East Africa conforms to a known pattern for closely related lark species to have disjunct distributions in southern and eastern Africa.

Indigenous knowledge on wild mushrooms in communities bordering miombo woodlands of central Zimbabwe

ABSTRACT Apart from timber, fruits, honey, firewood and other benefits from forests, mushrooms are an important forest food resource whose gathering has largely relied on indigenous knowledge systems (IKS). We surveyed five miombo woodland rural communities in central Zimbabwe with respondents of at least 16 years old, focusing on wild mushroom identification criteria used, ethnomycological knowledge transmission mechanisms, known mushroom foragers, known woody species associated with gathered mushrooms, and indigenous mushroom nomenclature systems used. Mushroom cap colour (99.52 %) was of similar importance to use of cap texture (95.78%) but more important (p ≤ .05) than cap shape, or other attributes. Women (69.04%) were more important (p ≤ .05) knowledge transmitters than other family members. Millipedes (91.79%) and insects (83.55%) constituted higher (p ≤ .05) mushroom foraging mention than other invertebrates. Julbernardia globiflora (84.16%) was more favourably mentioned (p ≤ .05) to associate with most mushrooms than other woody species. Mushroom nomenclature largely derived from their morphological traits, texture and habitat. The study demonstrates prevalence of moderately strong IKS and mushroom links to vegetation. These findings will help in ethnomycological research on aspects of miombo mushrooms and any relevant forest policy to benefit rural communities.

Climate change diminishes the potential habitat of the bont tick (Amblyomma hebraeum): evidence from Mashonaland Central Province, Zimbabwe

BackgroundUnderstanding the response of vector habitats to climate change is essential for vector management. Increasingly, there is fear that climate change may cause vectors to be more important for animal husbandry in the future. Therefore, knowledge about the current and future spatial distribution of vectors, including ticks (Ixodida), is progressively becoming more critical to animal disease control.MethodsOur study produced present (2018) and future (2050) bont tick (Amblyomma hebraeum) niche models for Mashonaland Central Province, Zimbabwe. Specifically, our approach used the Ensemble algorithm in Biomod2 package in R 3.4.4 with a suite of physical and anthropogenic covariates against the tick’s presence-only location data obtained from cattle dipping facilities.ResultsOur models showed that currently (the year 2018) the bont tick potentially occurs in 17,008 km2, which is 60% of Mashonaland Central Province. However, the models showed that in the future (the year 2050), the bont tick will occur in 13,323 km2, which is 47% of Mashonaland Central Province. Thus, the models predicted an ~ 13% reduction in the potential habitat, about 3685 km2 of the study area. Temperature, elevation and rainfall were the most important variables explaining the present and future potential habitat of the bont tick.ConclusionResults of our study are essential in informing programmes that seek to control the bont tick in Mashonaland Central Province, Zimbabwe and similar environments.Graphical

(Re)Presenting the role of iconography in African Christian liturgy: A case study of Serima Mission in the Catholic Diocese of Gweru in Zimbabwe (1948–2021)

This article examines the role of iconography in African Christian liturgy with a particular focus on Serima Mission in the now Catholic Diocese of Gweru in Central Zimbabwe. Of all Catholic missions in Zimbabwe, Serima Mission is perhaps the most popular in iconography with innumerable sets of wood and stone carvings portraying mostly religious scenes based on African designs and patterns. The atmosphere at Serima Mission, particularly the church interior, presents an expression of the power of African art, visual language, summation of the Catholic faith, and the otherness and transcendental nature of the omniscient, omnipotent, and omnibenevolent Christian God. This article firstly presents the history and impact of Serima African School of iconography under the tutelage of Fr John Groeber. Furthermore, it explores the role of iconography in African Christian liturgy on the Roman Catholic Church. The article critically examines iconography in African religion and spirituality, Sacred Scripture and celebrated traditional Christian practices. This article argues that, whilst religious symbols are on the physical realm, in reality, they symbolise and represent the metaphysical and transcendental realities. Although, they are often associated with religious formalism, exaggerated spirituality, and idol worship, icons and images have conveyed unprecedented allegorical messages across time and cultures.Contribution: This article expands the studies of iconography and semiology in theological landscapes and texts, allowing for the recognition and repositioning of art interpretation from an African experience.

Short duration overnight cattle kraaling in natural rangelands leads to increased tree damage by elephants

AbstractElephants are attracted to nutrient hotspots created through short duration overnight cattle corralling (hereafter kraaling) in natural rangelands at Debshan, a mixed cattle-wildlife private ranch in central Zimbabwe, causing severe tree damage. We determined the effect of age of nutrient hotspot (i.e., time after kraal use) on elephant use and the extent of tree damage. Elephant use and tree damage were assessed in nutrient hotspots of varying ages (6, 12, 24, 36 and 48 months after kraal use) and in surrounding landscape. We also compared Acacia karroo bark nutrient and soil nutrient concentration between nutrient hotspots (24 months after kraal use) and the surrounding landscape. Elephant use of nutrient hotspots was highest at 12 and 24 months after kraaling. The most severely damaged trees were in the 12-, 24- and 36-month-old nutrient hotspots. Acacia karroo bark nutrient concentrations (nitrogen, potassium, calcium, magnesium and iron) were higher in nutrient hotspots than surrounding vegetation, while soil nutrients (nitrogen, phosphorus, calcium and potassium) were higher in nutrient hotspots than surrounding landscape. We concluded that elephants mostly used nutrient hotspots 12 and 24 months after kraaling, while severe tree damage occurred 12, 24 and 36 months after kraal use.

Effects of nitrogen fertilizer application rate and time to first harvest on leaf area index; leaf nitrate content and yield of irrigated leaf rape (Brassica napus L. var. Giant)

In Zimbabwe, smallholder cultivation of leaf rape is of considerable importance due to the increasing demand for the leaf vegetable from the rapidly increasing urban populations. A two-season field trial was conducted in the Agricultural Practice Experimental Plots of the Midlands State University in central Zimbabwe. The objective of the study was to establish selected biometric responses of leaf rape to N fertilizer rates and time to first harvesting. Increasing the rate of N fertilizer application considerably improves the yield of fresh rape leaf; LAI and concentration of leaf nitrate. Delaying rape leaf harvest after N fertilizer side dressing can be used as a strategy to boost rape leaf yield for vegetable markets with high single delivery demand. When harvesting is deliberately delayed after N fertilizer application rape LAI are significantly increased. Delaying the first leaf harvests by 7; 14 and 21 days after N fertilizer side dressing amendments increases the content of nitrate in fresh rape leaves. Fresh rape yield can be more accurately predicted by values of rape LAI. Nitrate concentrations in fresh rape leaf is a poor predictor of rape yield under field conditions.

Characteristics of herbaceous vegetation on abandoned fallow fields in south central Zimbabwe

Fields abandoned to fallow, due to biophysical and socio-economic factors in communal areas of Zimbabwe, are used for livestock grazing. A study was conducted to characterise vegetation from such fields, and assess its grazing suitability across four agroecological regions (AER II – AER V) characterised by annual rainfall ranging from 750 mm to 400 mm, and five categories of fallow age groups (0-5; 6-10; 11-20, > 20 years and normal rangeland). Most fallow fields did not mature into woodlands but remained grasslands with or without sparse shrubs regardless of the period of fallowing and AER because of high stocking rates. There were no variations in palatability, ecological value, diversity, biomass and grazing capacity across fallow age groups. However, significant differences were observed across AERs. The quality of vegetation from fallows in AER II and III was poor but good in AER IV and V. The quantity of vegetation from fallows in AER II was higher than from other AERs. However, all fallow fields from the four AERs had low grazing capacity than expected from literature. We conclude that using fallow fields for uncontrolled grazing is unsustainable. There is need to investigate better management strategies for livestock production in fallow fields.

Clustering time trends of breast cancer incidence in Africa: a 27-year longitudinal study in 53 countries

Breast cancer is the most common, frequently diagnosed cancer with the highest incidence among female worldwide. Although the incidence is decreasing in developed countries, it is on increase in most of the African countries. This study aimed to identify different time trends of breast cancer incidence among African countries using latent mixture approach. The information includes newly diagnosed breast cancer patients per 100,000 women for 53 African countries in a period of 1990-2016. Latent mixture modeling was performed in Mplus 7.4 software. The overall trend of breast cancer in Africa was increasing. Latent mixture model with 5 clusters was estimated as the best using fit indices and linear growth trajectories were specified for each cluster. Nigeria was the only country which belongs to a cluster with negative slope indicating a slow decrease in the breast cancer incidence; also, Seychelles was the only country that showed a sharp increase over time. 31 countries belonged to a cluster with a slope of 0.08, indicating that the incidence of breast cancer is almost constant over time. Cluster 3 including Algeria, Angola, Botswana, Central African Republic, Cote d'lvoire, Equatorial Guinea, Lesotho, Libya, Namibia, Somalia, Sudan, Swaziland, Uganda and Zimbabwe and cluster 2 including Gabon, Mauritius, Morocco, South Africa, Tunisia and Congo showed a slow and moderate increase in the incidence of breast cancer, respectively. Providing health education programs is essential in African countries with rising trend of breast cancer during the last decades.

New geochronological constraints on the middle Archean Shurugwi greenstone belt toward an understanding of the crustal evolution of the Zimbabwe Craton

The Shurugwi greenstone belt (SGB) in the central Zimbabwe Craton is one of the major volcano-sedimentary belts in the craton, but its formation age and tectonic history have not been well constrained. For revealing the evolution of SGB, this study performed in-situ U–Pb dating of zircons from meta-sedimentary rocks of the Wanderer and Mont d’Or formations in SGB, granitoids/orthogneisses around SGB, and also whole-rock Re–Os isotopic analysis of chromitite in an ultramafic unit in SGB. Igneous zircons from granitoids which intruded into SGB were dated ca. 2.91 Ga, whereas those from the orthogneiss were dated ca. 3.01 Ga. The Re–Os isotopic analysis provided an intrusive age of ca. 3.0 Ga for the ultramafic unit that is unconformably covered by the Wanderer Formation. These ages indicate that the Wanderer Formation was deposited between 3.0 and 2.91 Ga and the SGB was tectonically emplaced over the basement with 3.01 Ga orthogneiss. By ca. 2.91 Ga. The depositional age of the Mont d’Or Formation is constrained between ca. 3.59 Ga and 3.0 Ga nonetheless the age range is still large. The age spectrum of the detrital zircons from the Mont d’Or Formation resembles that of the Wanderer Formation, sharing a dominant age cluster at ca. 3.59 Ga. For the Wanderer Formation, a significant time gap of nearly 600 million years between the depositional age and the 3.59 Ga major cluster in detrital zircon age spectra suggests that the SGB had a remarkable provenance which prevented large-scale supply of young detrital grains from tectono-magmatically active region.

Soil fertility status of abandoned fields in smallholder agriculture in South Central Zimbabwe

In Zimbabwe, because of shortages of land, there is need to establish whether soil fertility improves over time in abandoned fields. A study was undertaken in 2015 to characterize fertility status of abandoned fields in smallholder farming areas located in Buhera and Hwedza districts in Zimbabwe. Abandoned fields were divided into four categories based on years of being abandoned (0–5, 6–10, 11–20 and ≥ 20 years) across two soil types and agroecological gradient made up of four regions (AER II to V) where annual rainfall decreases from AER II to V. Soil samples were analysed for pH, N, P and K using standard laboratory methods. A survey was conducted to determine adequacy of nutrient resources used. Soil nutrients did not significantly vary (p > 0.05) with period of abandonment but varied with soil type and agroecological regions. Clay soils and soils from AER V had significantly high N, P and K content. In terms of adequacy of nutrients across all the three factors, N and P content were below required recommendations for crop production whilst K was adequate and soil pH was too acidic. With regards to fertilizer use, majority of the farmers failed to purchase mineral fertilizers because their annual cash earnings were far below money required. As a result 91% of the farmers were failing to apply recommended fertilizers for sustainable yields. In conclusion, abandoned fields in Zimbabwe's communal areas do not restore soil fertility regardless of period to which a field has been abandoned, soil texture or agroecological region. The fertility of these abandoned soils remains poor and too low for crop growth. Farmers are financially unable to meet soil nutrient requirements to improve fertility of their abandoned soils. These findings are important in determining appropriate measures to restore soil fertility and in determining efficient land use policing and planning measures.

Mobility, temporary migration and changing livelihoods in Zimbabwe's artisanal mining sector

This article examines mobility and trans-local livelihood practices linked to artisanal mining, exploring how movement in diverse socio-economic circumstances has profoundly shaped development dynamics in Zimbabwe. Following the fast-track land reforms in Zimbabwe, mobility across resettled large-scale (formerly white-owned) commercial farms created space for reshaping livelihoods across the country, and opened up mineral access to local populations. Beyond understanding mobility linked directly to land reform, we stress the need to appreciate diverse subsequent, interlinking and highly dynamic influences on mobility – as well as what mobility enables. We draw on ethnographic data gathered in three research sites in Mhondoro Ngezi district, in central Zimbabwe, analysing some of the changing socio-economic relations, exploitation concerns and opportunities linked to mobility and artisanal mining activities. As economic challenges have continued to multiply, the importance of artisanal mining – in many regions of the country – has intensified. Understanding mobility requires attention to both temporary and less temporary migration patterns and differentiated ways in which social networks and economic labour arrangements, including risks of mistreatment and new economic possibilities play out. We especially argue for more attention to varied forms of youth mobility and domestic migration around gold mining amid Zimbabwe's deep economic challenges.

Conservation agriculture as a climate change mitigation strategy in Zimbabwe

ABSTRACT There is a need to quantify agriculture’s potential to sequester carbon (C) to inform global approaches aimed at mitigating climate change effects. Many factors including climate, crop, soil management practices, and soil type can influence the contribution of agriculture to the global carbon cycle. The objective of this study was to investigate the C sequestration potential of conservation agriculture (CA) (defined by minimal soil disturbance, maintaining permanent soil cover, and crop rotations). This study used micrometeorological methods to measure carbon dioxide (CO2) flux from several alternative CA practices in Harare, central Zimbabwe. Micrometeorological methods can detect differences in total CO2 emissions of agricultural management practices; our results show that CA practices produce less CO2 emissions. Over three years of measurement, the mean and standard error (SE) of CO2 emissions for the plot with the most consistent CA practices was 0.564 ± 0.0122 g CO2 m−2 h−1, significantly less than 0.928 ± 0.00859 g CO2 m−2 h−1 for the conventional tillage practice. Overall CA practices of no-till with the use of cover crops produced fewer CO2 emissions than conventional tillage and fallow.

New land, old claims and the politics of belonging during a changing agrarian situation in central Zimbabwe

This article examines the way discourses of autochthony and belonging were deployed by various groups of people to make claims over land during the implementation of Zimbabwe’s Fast Track Land Reform Programme (FTLRP) in 2000. Although the FTLRP was not officially restitutive, people who occupied farms in Mhondoro Ngezi in central Zimbabwe claimed they were recovering their ancestral lands lost during colonial-era forced removals. As a result, discourses of autochthony and belonging became salient during land occupations. The paper concludes by arguing that claims of autochthony and belonging remain hugely contested and that such claims have underpinned the way various groups of people who occupied a former white-owned conservancy made claims over land and how they sought to legitimise such claims.

Supervision of Teachers in Mbire District Primary Schools in Zimbabwe: Working With Teachers for Effective Schools

Supervision is the process of working with teachers to improve their performance in their professional chores. This study sought to assess the impact of supervision of teachers by heads of schools in Mbire District in Central Zimbabwe. The study was quantitative and utilised a descriptive survey design. The population comprised of all primary school heads and teachers in Mbire District. The sample consisted of 200 teachers and 20 heads of schools. Of the sample respondents, 120 were males and 100 females. All the information was collected through a questionnaire which had both close-ended and open-ended questions. The study revealed that both teachers and heads concurred that supervision as it obtained in their schools needed more time and resources. It also revealed that heads were using models of supervision that did not promote teacher growth and motivation. The study recommends that heads of schools should not be allocated a class to teach if they are to effectively carry out their supervisory roles. The study also recommends that the Ministry of Primary and Secondary Education should organise workshops and in-service training sessions to help heads acquire better skills for supervising teachers.

Evolution of the North West Arm and the Central Sector of Mashava Igneous Complex in south central Zimbabwe from an investigation of its silicate minerals compositions

An investigation of the economically important Mashava Igneous Complex (MIC) in Zimbabwe was conducted using petrographic and silicate mineral compositions to gain some insights into its origin. The MIC, an ultramafic-mafic complex located in the western extremity of the Masvingo greenstone belt (MGSB), is composed of amphibole, serpentine, epidote, chlorite, clinopyroxene, orthopyroxene, plagioclase, and olivine. Spinel, sulfide minerals, and minor quartz as well as other opaque minerals are also present.The dominant mineral is serpentine, which displays a wide range in both FeO and SiO2 compositions, and the majority of this mineral belongs to the lizardite, chrysotile, and antigorite varieties. Amphiboles display a wide range in composition from tremolite and actinolite which are both consistent with greenschist facies metamorphism, through magnesiohornblende to tschermakite which are both consistent with amphibolite facies metamorphism. Clinozoisite is the only epidote type occurring in the MIC, whereas chlorite varies widely in composition which reflects the varying concentrations in iron and silica in this mineral. Chlorite types range from talc chlorite through penninite, diabantite, pycnochlorite, brunsvigite, ripidolite, and pseudothuringite.Plagioclase shows a wide compositional range from high albite to bytownite, with only two samples plotting in the alkali feldspar anorthoclase field. Pyroxene ranges in composition from enstatite through pigeonite and augite to diopside whereas olivine is rich in MgO with forsterite contents ranging from 80 to 89. Application of the chlorite geothermometry equation of Kranidiotis and MacLean (1987) yields temperatures ranging from ∼200–320 °C whereas temperatures ranging from 130 to 445 °C are obtained using equations of Lanari et al. (2014) for the formation of this mineral, generally consistent with low- to medium-grade metamorphic conditions.Chlorites in the North West Arm were formed at relatively lower temperatures (97–234 °C) than those at which chlorites in the Central Sector were formed (204–445 °C). Pressure estimates for the metamorphism of the MIC range from 3.8 to 7.3 kbars, which corresponds to depths of ∼13–25 km, respectively. Based on the different silicate mineral compositions of the North West Arm and the Central Sector, it is inferred that these two blocks underwent different petrogenetic and evolutionary histories but they were later juxtaposed, possibly during thrusting of the former onto its present position.