Browsing by Author "Msabi, Michael"

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    Analogue sandbox scaled modelling of oblique and orthogonal extension rifting in Rukwa rift basin, Tanzania
    (University of Dar es Salaam, 2021) Ojok, Tonny; Duot, John BK; Namaganda, Majorine; Sadiki, Nasra; Msabi, Michael
    Fault evolution in oblique and orthogonal rift systems in the brittle upper crust of the Rukwa rift basin was simulated using scaled sandbox modelling by varying the angle between the rift axis and the extension direction, α, through 45° and 90°, over a 10 cm displacement. The 45° oblique model exhibits a half-graben architecture bounded by a planar fault, intra-rift faults and a conjugate fault in some vertical sections. The map view of the model’s basin trends in the NW-SE direction, and is comparable with the Rukwa rift basin orientation. The 90° oblique model forms a basin structure which is orthogonal to the extension direction of the model in aerial photos. Its linear fault remains orthogonal to the extension direction, while the flexural side of the model segments into sinuous normal faults. Planar to slightly curved intra-rift faults are observed in vertical sections. The half-grabens have similar geometries in vertical sections for both models, while intra-rift faults elongate in vertical sections. The results of the oblique model are similar to natural examples of rift fault systems like the Rukwa rift. The fault geometries of the sandbox models can serve as examples for recognizing fault styles in oblique rift systems.
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    Data schemas for multiple hazards, exposure and vulnerability
    (Emerald Publishing Limited, 2019) Murnane, Richard J.; Allegri, Giovanni; Bushi, Alphonce; Dabbeek, Jamal; Moel, Hans de; Duncan, Melanie; Fraser, Stuart; Galasso, Carmine; Giovando, Cristiano; Henshaw, Paul; Horsburgh, Kevin; Huyck, Charles; Jenkins, Susanna; Johnson, Cassidy; Kamihanda, Godson; Kijazi, Justice; Kikwasi, Wilberforce; Kombe, Wilbard; Loughlin, Susan; Løvholt, Finn; Masanja, Alex; Mbongoni, Gabriel; Minas, Stelios; Msabi, Michael; Msechu, Maruvuko; Mtongori, Habiba; Nadim, Farrokh; O’Hara, Mhairi; Pagani, Marco; Phillips, Emma; Rossetto, Tiziana; Rudari, Roberto; Sangana, Peter; Silva, Vitor; Twigg, John; Uhinga, Guido; Verrucci, Enrica
    Purpose: Using risk-related data often require a significant amount of upfront work to collect, extract and transform data. In addition, the lack of a consistent data structure hinders the development of tools that can be used with more than one set of data. The purpose of this paper is to report on an effort to solve these problems through the development of extensible, internally consistent schemas for risk-related data. Method: The consortia coordinated their efforts so the hazard, exposure and vulnerability schemas are compatible. Hazard data can be provided as either event footprints or stochastic catalogs. Exposure classes include buildings, infrastructure, agriculture, livestock, forestry and socio-economic data. The vulnerability component includes fragility and vulnerability functions and indicators for physical and social vulnerability. The schemas also provide the ability to define uncertainties and allow the scoring of vulnerability data for relevance and quality. Findings: As a proof of concept, the schemas were populated with data for Tanzania and with exposure data for several other countries. Research limitations/implications: The data schema and data exploration tool are open sources and, if widely accepted, could become widely used by practitioners. Practical implications: A single set of hazard, exposure and vulnerability schemas will not fit all purposes. Tools will be needed to transform the data into other formats.
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    Mineralogy and Geochemistry of shale-hosted copper of the middle Buanji group, Chimala area, South-Western Tanzania
    (College of Natural and Applied Sciences, University of Dar es Salaam, 2021) Mutasingwa, Almachius; Msabi, Michael; Jackson, Neema; Jagarlamudi, Seetharamaiah
    The mineralogical and geochemical assessments are presented in this paper to constrain the mineralogy and copper concentrations of the shale-hosted copper in the Middle Buanji Group of the Upper Paleoproterozoic (1.67 Ga). The XRD analysis revealed that illite and chamosite are the major clay minerals present in the shales together with pseudomalachite, quartz, and muscovite that constitute over 95% by proportion of the sample. The minerals biotite, birnessite, ferroselite, bearsite, chloritoid, and anatase are present in association with shale-hosted copper in low amounts (i.e., <5% by proportion of the sample). The pseudomalachite [Cu5(PO4)2(OH)4] is considered as ore mineral of copper in the shales of the Middle Buanji Group. Field observations revealed the presence of different shale layers within the Middle Buanji Group such as red, grey and green/blue in which copper mineral is distributed. On average, the copper concentrations in the shale layers were unevenly distributed throughout the red-grey-green shales layers with values of 0.31 wt%, 5.2 wt% and 13.19 wt%, respectively. A noticeable amount of copper mineralization up to 25.7 wt% was restricted within the green shale layer as compared to red (0.31 wt%) and grey (10.9 wt%) layers.
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    Potential landfill sites selection using GIS-based multi-criteria decision analysis in Dodoma capital city, central Tanzania
    (Springer Nature, 2021) Makonyo, Michael; Msabi, Michael
    Solid waste management is a global challenge, especially in developing countries due to the rapid increase in population and urbanization where the availability of sanitary landfills is inevitable. Determining suitable landfill sites is a fundamental aspect for new and rapidly growing cities. The current study is aimed at selecting potential landfill sites using GIS-based multi-criteria decision analysis in Dodoma capital city. Fifteen criteria including proximity from built-up areas, surface water, boreholes, sensitive sites including social service areas, episodic water channels, protected areas including historical sites, faults, land use/land cover, geology, soil type, elevation, slopes, airport, roads, and earthquake epicentres were integrated with the help of analytical hierarchy process (AHP). The landfill sites’ suitability map was produced based on the weighted linear combination method and assigned suitability classes as highly suitable, suitable, moderately suitable, less suitable, and unsuitable. The overall suitability results show that 41,177 ha (14.7%) of the study area is determined as highly suitable for landfills site location. The remaining 83,930 ha (30%), 84,305 ha (30.2%), and 53,508 ha (19.1%) of the area are suitable, moderately suitable, and less suitable respectively while 16,683 ha (6%) is under the unsuitable zone. From the highly suitable area, eleven candidate landfill sites were selected and prioritized using the AHP technique. The final results show landfill site 3 (10,361.94 ha), 5 (3717.85 ha), and 2 (3535.86 ha) were found to be the most highly suitable sites with eigenvector weight of 0.147, 0.122, and 0.121 respectively. Landfill sites 8, 7, and 6 were lastly considered. Field observation involving expertise from geology, hydrogeology, geophysical, and environment confirmed the suitability of selected sites. Thus, these techniques can be employed in developing countries to locate suitable landfill sites to minimize health and environmental impacts.
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    Sedimentology and compositional characteristics of siliciclastic and associated sediments in Ruvu basin: implication on paleo-depositional environment, provenance, and tectonic setting
    (Informa UK Limited, 2021) Godfray, Godson; Kabohola, Joyna; Msabi, Michael
    The paleo-depositional environment of theRuvu basin ranges from alluvial,floodplain, low- and high-energy fluvial channels, and deltaic sub-environments of Ngerengere beds, Tanga beds, and Jurassic Msata formations. Amboni limestones that overlap the Karoo sequences, Bagamoyo Formation and Sakura Formation were probably deposited in a shallow marineenvironment. Trace elements show that the sediments were deposited in oxic environments with a V/Cr ratio of 0.85 and Ni/Co ratio of 2.9 to anoxic environments with a V/Cr ratio >4.3.Low Cr, Ni, Co, and V, high Y/Ni and Zr/Crratios of up to 0.83 and 3.6, respectively, and low Ti/Zr ratios ranging from 0.004 to 0.01 indicate a contribution from afelsic source, and few ratios >1show some contribution from a mafic source. This is supported by the diverse enrichment inlight rare earth elements (LREEs), small negative Eu anomaliesand modest heavy REEs reflecting a dominantly granitic source. Theprovenance is probably from the Usagaran mobile belt and Proterozoic Mozambiquemobile belt. The cross-plot between Th and Ta from midJurassic to Cretaceoussediments indicates that the basin was essentially developed as a passivecontinental margin; however, discriminant factor plots of the Karoo indicatethe existence of a rift setting.
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    Unconventional hydrocarbon resources in Tanzania: insight from geology and previous exploration of conventional resources
    (Springer, 2021) Godfray, Godson; Msabi, Michael
    Unconventional oil and gas exploration has been developing rapidly in recent decades, while Tanzania has been paid very little consideration. This review aimed to infer these unconventional hydrocarbon resources in some basins, mostly the intracratonic Karoo basins and one coastal basin (Ruvu basin), from a piece of the very limited information available from the previous exploration of conventional resources. The presence of thick dark carbonaceous shales of Makarawe formation at Ruvu basin with TOC% 2.4–4.0% and a thickness between 107 and 698 m capped with non-porous oncolitic limestone and the gas shows encountered at an interval of 107 m of Makarawe shales at Makarawe-1 well makes Ruvu basin as important play for unconventional shale gas. The intracratonic Karoo basins have a thick deposit of Karoo sediments interbedded with coal deposits. Coal bedded methane has been encountered in a deep coal exploration borehole at Songwe-Kiwira coalfield. Geochemical analysis of outcrop samples from Namwele, Mbamba Bay, Njuga, and Mhukuru coalfields shows that the interbeds of coal-carbonaceous shales/mudstone have the rich organic matter of type III or both II and III and trace of oil on samples from Ketewaka and Ngaka coalfield make these sub-basins to be considered as potential plays for shale oil/gas. The presence of probable shale gas resources ranging from 50 to 200 trillion cubic feet at the Selous basin increases Karoo basins’ potentiality in exploring unconventional gas resources. In addition to the discovered conventional gas resource in offshore Tanzania, any unconventional resources will impact the country’s economic growth.