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Engineering Geological Mapping Of Dar Es Salaam City, Tanzania, K. A. Msindai
Engineering Geological Mapping Of Dar Es Salaam City, Tanzania, K. A. Msindai
Tanzania Journal of Science
Engineering geological mapping of Dar es Salaam city in Tanzania has been carried out using desk studies supplemented by field reconnaissance as well as limited laboratory tests. Desk studies involved interpretation of medium to large-scale topographical maps, Landsat imagery and sequential aerial photographs from 1953-1990. These studies also evaluated small to medium scale geological, pedological maps together with ground water data from 50 boreholes. Two basic maps were prepared, namely, geomorphological and geological map depicts the spatial extent of the Neogene geological formations. Three distinct sandstone terraces could be distinguished in Dar es Salaam region at 0-15 m and 30 …
Comparison Of Various Methods For Estimating Wave Incident Angles In The Nearshore Zone, As Ngusaru
Comparison Of Various Methods For Estimating Wave Incident Angles In The Nearshore Zone, As Ngusaru
Tanzania Journal of Science
Five different methods were examined for their suitability in estimating the inshore wave incident angles on a nearshore zone with a complex topography. Visual observation provided preliminary estimates. Two frequency independent methods and one frequency dependent method based on current meter measurements were examined. Another frequency dependent method based on collocated bottom pressure and current meter measurements was also examined. The results from all the methods provided a reasonably consistent estimate of the inshore wave incident angles. The frequency independent methods gave exactly the same results while the frequency dependent methods had a 5% relative error among themselves. Between frequency …
The Polarising Effects In Sintered Kaolin, Fm D'Ujanga, Y Kaahwa, L Atteraas
The Polarising Effects In Sintered Kaolin, Fm D'Ujanga, Y Kaahwa, L Atteraas
Tanzania Journal of Science
The polarizing effects in sintered kaolin samples were analysed in terms of the sample density (or porosity) using direct current (dc) techniques. More porous samples exhibited higher polarizing effects than the less porous ones. The conduction carriers in kaolin samples at room temperature were found to be mainly electrons, with ionic conduction being enhanced by the moisture content with the pores. The influence of the uniaxial pressure and particle-size on the compacted and sintered density of the ceramic have been studied, and a density-pressure relationship before- and after-sintering conditions obtained
Studies On Benthic Denitrification In The Chwaka Bay Mangrove Sediments, Zanzibar, Sm Mahommed, Rw Johnstone
Studies On Benthic Denitrification In The Chwaka Bay Mangrove Sediments, Zanzibar, Sm Mahommed, Rw Johnstone
Tanzania Journal of Science
Denitrification was measured at three sites in a narrow tidal creek in the Chwaka mangrove ecosystem. Denitrification arising from water column nitrate (Dw) was low (< 0.1μM Nm-2h-1) and there was little spatial and seasonal variation in Dw rates in the creek. Coupled nitrification-denitrification (Dn) was found to be low, but within the range measured in other mangrove sediments. Average values ranged from 0.01 to 0.45 μM Nm-2h-1 and showed strong spatial variations. The low denitrifcation rates observed in the creek were possibly as a result of the low availability of NO3 and high C:N values of the organic matter in the sediment. Spatial variations in denitrification rates were due to variations in concentration levels of organic matter and possibly to disproportionate competition for inorganic nitrogen between denitrifiers and benthic autotrophs among sites. There were no seasonal differences in denitrification rates. Results from the present study suggest that sediment denitrification does not play a major role as a sink for N in this ecosystem
Interpretation Of Refelction Seismic Data From The Usangu Basin, East African Rift System, Ei Mbede
Interpretation Of Refelction Seismic Data From The Usangu Basin, East African Rift System, Ei Mbede
Tanzania Journal of Science
Reflection seismic data collected by AMOCO Tanzania Oil Company in the 80s, are herin used to correlate the main Usangu Basin parameters to those estimated from outcrop, gravity and aeromagnetic data. The seismic data are further used to constrain the geometry of crustal extension in this south-western sector of the East African Rift System (EARS) in Tanzania. Three distinct sedimentary packages on top of the basement reflector are interpreted and correlated to the Permo-Carboniferous Karoo rocks, the Jurassic/Cretaceous and Miocene Red Sandstone Group and Miocene to recent Lake Beds in the adjacent Rukwa basin, where the ages of the sedimentary …
Tectonic Setting Of Gabbroic Rocks In The Western Part Of The Lupa Gold Field, South-West Tanzania, Sr Mnali
Tectonic Setting Of Gabbroic Rocks In The Western Part Of The Lupa Gold Field, South-West Tanzania, Sr Mnali
Tanzania Journal of Science
There is a pronounced occurrence of gabbroic rocks in the western part of the Lupa gold field, SW Tanzania. These rocks occur in the peripheral part around the Saza-Chuya granodiorite with which it makes a gradiational, unchilled contact. The rocks have been altered or metamorphosed to low-grade greenschist facies as indicated by the presence of secondary epidote, penninite, chlorite, sericite and calcite. The majority of major-element oxides show scattered variation trends against immobile elements such as Zr, indicating some degree of element mobility during post-crystallization processes of alteration or metamorphism. Major-trace-element data show that the gabbroic rocks in the study …
Tectonic Setting And Uplift Analysis Of The Pangani Rift Basin In Northern Tanzania Using Apatite Fission Track Thermochronology, E. I. Mbede
Tanzania Journal of Science
Thirty four new Apatite Fission Track (AFT) ages and 32 track length distributions from samples of basement rocks flanking the Pangani rift, East African Rift System (EARS) are presented, in an attempt to elucidate the uplift and erosion of the rift flanks. The ages fall in the range of 207±15 to 48±4 Ma, spanning from Early Jurassic to Early Tertiary. These ages are much younger than the last termal event in the Mozambique belt that form the basement complex and are interpreted to represent the most recent tectonic events. Track length (TL) distributions suggest that uplift and erosion of the …
The Emplacement Age Of Gabbroic Rocks And Associated Granitoids Of The Liganga-Msanyo Complex, South Eastern Tanzania, M. A. H. Maboko
The Emplacement Age Of Gabbroic Rocks And Associated Granitoids Of The Liganga-Msanyo Complex, South Eastern Tanzania, M. A. H. Maboko
Tanzania Journal of Science
The Msanyo Gabbro and the associated Mdando granitoids, which intrude Paleoproterozoic high-grade metamorphic rocks of the Ubendian Belt in southern Tanzania, yield imprecise Sm-Nd whole rock isochron ages of 1608±134 Ma (ε (Nd) = 2.1) and 1642±100 Ma (ε (Nd) = 1.6), respectively. These ages are indistinguishable at the 95% confidence level, indicating that the two rock suites were intruded at the same time. A more precise estimate of the time of emplacement is provided by a 5-point mineral isochron age of 1505±42 obtained from one of the gabbro samples. Calculated initial ε (Nd) values and mean crustal residence ages …
Subsidence History Of The Rukwa Rift In South West Tanzania Analysed From Ivuna Well, E I Mbede
Subsidence History Of The Rukwa Rift In South West Tanzania Analysed From Ivuna Well, E I Mbede
Tanzania Journal of Science
The variation in subsidence rate during rift basin development is a good indication for the Geodynamic history of a sedimentary basin. The sedimentary section of Ivuna Well is herein used to explain the structural evolution of Rukwa Basin within the Western Rift of the East African Rift System. The sedimentary record of Ivuna Well is extracted from published information. The effects of sedimentary load, corrected for compaction and variation in water depth, and lake-level have been removed to obtain the "tectonic subsidence." Curves show two phases of accelerated subsidence related to the fault controlled rifting phases: The Karoo rifting and …
Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo
Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo
Tanzania Journal of Science
Time series data of currents and sea current levels recorded by current meter and tide gauges, respectively from Chwaka Bay, Zanzibar were obtained from the entrance near to Mapopwe Creek and at the middle of the bay. The analysis of the data reveals that the tidal currents had an asymmetry near the entrance to Mapopwe Creek where the ebb currents were stronger than flood currents although the ebb periods were considerably longer than flood periods.
Facies Analysis Of Limestones At Songo Songo Island In South East Tanzania, S Kapilima, Ka Msindai
Facies Analysis Of Limestones At Songo Songo Island In South East Tanzania, S Kapilima, Ka Msindai
Tanzania Journal of Science
Songo Songo Island is situated at close proximity of the continental slope of the coastal sedimentary basin of Tanzania. Its rich varieties of marine organisms and carbonate sediments provide a classic example of island emergence with the development of successive detrital and organic reefs as well as lime sand. Facies analysis at the Island was done through mapping, logging, faces and microfacies analysis. Results show that Songo Songo Island can be classified into three faces; the detrital reefs, organic reef and lime sand. The fossil assemblage reveals that most of the fauna and flora are frame-building organisms in organic reef. …
Application Of Multivariate Analysis In The Exploration For Tin In Granites: A Study Of Granites From Northwestern Tanzania Using Discriminant Function And Factor Analysis, J.R. Ikingura
Tanzania Journal of Science
Variations in major and trace element Composition of granites from Karagwe-Ankolean (NE Kibaran) belt in northwestern Tanzania have been investigated by factor analysis and discriminant function statistical methods, The variations are attributed to three main factors. Factor 1 is positively loaded with CaO, MgO, Fe2O3 (Fe total), TiO2, MnO, Ba, Sr, Zr and Y, and negatively loaded with P2O5, SiO2, B and Rb. Factor 2 is positively loaded with Na2O, P2O5 Mno, Sn, Li, Rb and Y, and negatively loaded with TiO2, K2 …
Uplift And Erosion Of The Livingstone Basin Rift Flanks, Malawi (Nyasa) Rift, East Africa: Apatite Fission Track Analysis, Mbede E. I
Tanzania Journal of Science
Apatite fission track (AFT) dating is a method applied in neotectonic studies of sedimentary basin and in constraining uplift histories of rift flanks. Dating of 20 AFT samples of basement rocks flanking the Livingstone (Karonga/Tukuyu) basin on the northern edge of the Malawi (Nyasa) rift is used to analyse the uplift and erosionofthe basin flanks. Results suggest that in the Livingstone basin, rift-related uplift and erosion of the flanks has modified the topographic patterns. The high elevation of the Livingstone Mountains is related to regionally distributed isostatic rebound, whereas the topography of the hanging wall flank has probably been severely …
Gravity Data Interpretation Of The Usangu Baisin Tanzania, I.M. Marobhe, E.I. Mbede
Gravity Data Interpretation Of The Usangu Baisin Tanzania, I.M. Marobhe, E.I. Mbede
Tanzania Journal of Science
The shape and geometry of Rift of basins is best expressed by looking at the depth to basement maps. It is now an accepted idea that the Rift basins are spoon shaped bounded on one side by a border fault (BF) which is normally the side of maximum sediment deposition. Gravity data from Usangu Basin collected by Amoco in 1985 are here interpreted to decipher the shape and the geometry of the Basin. Results suggest that the Usangu basin shape is similar to the other Rift Basins within the East African Rift System (EARS). The basin, is however, traversed by …
Natural Zeolites For Pollution Control An Overview, M.M. Makweba
Natural Zeolites For Pollution Control An Overview, M.M. Makweba
Tanzania Journal of Science
Natural zeolites are minerals characterized by a framework of alumino-silicate whose structure contains channels occupied by water and exchangeable cations. The common known zeolites which occur in sedimentary rocks of volcanic origin include analcime, clinoptilolite, heulandite laumontite, philipsite, chabazite, erionite and mordenite. The zeolites have been studied in detail on their physical and chemical propertied. The ability of zeolite minerals like clinoptilolite to remove Cs-137 and Sr-90 from radioactive waste waters and to remove ammonium ions from municipal waste waters has been a milestone for zeolites to be applicable in pollution control. In Tanzania, zeolites occurrences have been reported in …
Algal Stromatolites From The Late Permian Lacustrine Sediments Of Tanzania, C.Z. Kaaya
Algal Stromatolites From The Late Permian Lacustrine Sediments Of Tanzania, C.Z. Kaaya
Tanzania Journal of Science
Thin bed of algal stromatolites and oolites occur within a distinct stratigraphic unit (60-120 m thick) in the Late Permian (Karoo) lacustrine sedimetns of the Ruhuhu Basin in SW Tanzania. The stromatolites vary from a few centimeters to 50 cm high and exhibit 4 morphotypes: 1) bulbous or domal 2) columnar. Branching and non-branching varieties are common in the two morphotypes. The other two are : 3) laminated mats and 4) oncolites. All four types may occur in one bed. Filamentous algae were responsible for the building up of the stromatolites in which there was more precipitation of calcite than …
Determination Of Tine In Geological Samples By Energy Dispersive X-Ray Fluorescence With A Secondary Target, J. M. J. Kahatano, M. Mwambeule
Determination Of Tine In Geological Samples By Energy Dispersive X-Ray Fluorescence With A Secondary Target, J. M. J. Kahatano, M. Mwambeule
Tanzania Journal of Science
Tin has been determined in seven international geochemical reference samples with energy-dispersive X-Ray Fluorescence using an X-ray tube with a secondary target, after optimization of the working parameters and instrument settings. The tin values obtained in this work quite satisfactorily lie within ranges reported in the literature or recommended by the suppliers of the reference samples. The method can therefore be applied to supplement other analytical techniques in the elemental analysis of geochemical samples.
Physical Controls Of Mud Deposition In A Backbarrier System, Spiekeroog Island German Wadden Sea, N. Nyandwi
Physical Controls Of Mud Deposition In A Backbarrier System, Spiekeroog Island German Wadden Sea, N. Nyandwi
Tanzania Journal of Science
The areal distribution of the mean grain size of the sand fraction indicates presence of a shore-normal energy gradient with a shoreward fining from a mean grain size of 2.0 phi (0.25 mm) on Spiekeroog island to 3.5 phi (0.09) mm) near the dyke which forms the landward boundary of the tidal flat. This energy gradient is also reflected by the shoreward increase in the mud content of the sediment. Until recently, the relation of the mud distribution to the energy level variation in the Wadden Sea was not clearly known. Purely mud zones (˃ 50% mud) occur in the …
Stratigraphy And Tectonic Evolution Of The Palaeoproterozoic Usagaran Belt In South-Eastern Tanzania, A.H. Mruma
Stratigraphy And Tectonic Evolution Of The Palaeoproterozoic Usagaran Belt In South-Eastern Tanzania, A.H. Mruma
Tanzania Journal of Science
The palaeoproterzoic Usagaran Belt is bordered by the Archaean Tanzanian Craton to the NW and the Mozambique Belt to the east. It is made up of the following three stratigraphic units:- (i) The lithodemic sillimanite, kyanite and cordierite gneiss lithodemes and pyroxene-garnet amphibolite lithodemes (ii) The lithostratigraphic Konse Group : greenschist to lower amphibolite facies metasedimentary and metavolcanic formations. (iii) The metavolcanic Ndembera Group; a possible lateral equivalent of the konse. Furthermore, the belt contains a post-tectonic gabbro-granitoid suite. The mutual stratigraphic relationship of the konse and Isimani has been a matter of dispute. However, the field observations described in …
The Mozambique Of Eastern Tanzania: Evidence For Pan-African Reactivation Of Early Proterozoic Usagaran Basement, M.A.H. Maboko
The Mozambique Of Eastern Tanzania: Evidence For Pan-African Reactivation Of Early Proterozoic Usagaran Basement, M.A.H. Maboko
Tanzania Journal of Science
The high grade metamorphic rocks of Eastern Tanzania belong to two distinct tectonothermal belts; the early Proterozoic Usagaran Belt and the late Proterozoic (Pan–African) Mozambique Belt. Rocks of the Usagaran Belt, which locally sow evidence of eclogite facies metamorphism, experienced peak metamorphic conditions at ⁓ 2000 Ma. Tectonic activity in the Usagaran added at ⁓ 1800 Ma with the emplacement of post-organic granites. In contrast, the Mozambique Belt, which is characterized by extensive granulite complexes, experienced peak metamorphic conditions at about 700 Ma. Due to the similarity of both structural trends and metamorphic grade, the boundary between the two belts …
Weathering On The Alkaline Rocks Of The Mbozi Gabbro Syenite Complex Sw–Tanzanian, East Africa, M.K.D. Mutakyahwa
Weathering On The Alkaline Rocks Of The Mbozi Gabbro Syenite Complex Sw–Tanzanian, East Africa, M.K.D. Mutakyahwa
Tanzania Journal of Science
The Mbozi gabbro syenite complex is about 800 Ma and is associated with the Bukoban tectonic episode. Tectonically it follows the regional strike direction of the Ubendian System, which is a part of the polycyclic Mozambique mobile belt. The complex is a typical ring structure with the central part down-faulted. Deep weathering profiles on the ring structure were developed on a peneplain and as a result of uplift intersected hilly landscape of early tertiary times. The truncated 5-15m thick weathering profiles occur on three rock types, olivine gabbro, pyroxenite and nepheline perthite syenite (pethoste). The chemical and mineralogical processes of …
Palynostratigraphy Of Cretaceous Sediments, Rufiji Basin, Tanzania, E. Msaky
Palynostratigraphy Of Cretaceous Sediments, Rufiji Basin, Tanzania, E. Msaky
Tanzania Journal of Science
Cretaceous sediments from Luhio - 1 borehole drilled in the Rufiji basin yielded a palynomorph assemblage of spromorphs and dinoflagellate cyst species. The age of the sediments penetrated ranges from Early Cretaceous (Albian) to Late Cretaceous (Senonian). The Early Cretaceous is characterized by presence of the following dinocyst key species: Litosphaeridium arundum, Dinopterygium tuberculatum, Florentinia Cooksoniae, Systematophora cretacea and Oligosphaeridium pulcherrimum. The Late Cretaceous (Senonian) is characterized by the presence of the following dinocyst key species: Cannosphaeropsis utinensis, Dionogymnium pustulicostatum, Florentinia ferox, Odontochitina porifera, Odontochitina operculata, Xenascus sarjeantii and Xiphophoridium asteriforme …
Silica Spherules In Chrysoprase From Haneti-Itiso Area, Cental Tanzania, E.P. Malisa
Silica Spherules In Chrysoprase From Haneti-Itiso Area, Cental Tanzania, E.P. Malisa
Tanzania Journal of Science
Apple green gem quality chrysoprase from haneti-Itiso area, central Tanzania was studied. Under the microscope the chrysoprase shows highly disordered spherules which are concentric. Composed of bipyramidal quartz, chalcedony quartzite and opal-A. The spherules were classified into four main types according to the shell arrangement. The diameter of the spherules ranged from 40 μm 77 μm. Fluid inclusion types in bipyramidal quartz were monophasic low temperature type. Mineralogical properties indicated refractive indices to be 1.548 to 1.553 (±0.002), mean specific gravity 2.56, hardness about 7 on Moho’s scale, inert to ultraviolet radiation, green though Chelsea filter, and absorption in the …
Trials With Trickle Irrigation Equipment At Morogoro Preliminary Report, M.E. Parkes, M. E. Madata
Trials With Trickle Irrigation Equipment At Morogoro Preliminary Report, M.E. Parkes, M. E. Madata
Tanzania Journal of Science
The use of trickle irrigation is discussed with reference to Tanzania. A split-split plot design experiment is described in which yields of tomato, onion, and cabbage are compared for trickle and hand-irrigated plots, with different levels of fertiliser treatment. Yields for trickle-irrigated plots were significantly greater only for tomatoes. These results were achieved during July to October and a second attempt to grow the same vegetables during December to March was unsuccessful. Further trials are required to obtain a suitable rotation of vegetable crops from both a nutritional and agronomic point of view. Experience with the trickle irrigation equipment is …
Theoretical Evaluation Of Selective Radiation–Absorbing Surface, K.R. O’Shea
Theoretical Evaluation Of Selective Radiation–Absorbing Surface, K.R. O’Shea
Tanzania Journal of Science
An algol computer program is described, by means of which the spectral reflectivity for any angle of incidence may be calculated for a surface consisting of up to two thin absorbing films on a bulk substrate. The values of optical constant, n and k, for the materials used and also the thickness of the films, are the only data required. Calculated reflectivities have been shown to be consistent with experimental results.
The Separation And Analysis Of Titanium And Iron In The Mineral Ilmenite, Adolf M Mulokozi
The Separation And Analysis Of Titanium And Iron In The Mineral Ilmenite, Adolf M Mulokozi
Tanzania Journal of Science
Since the location of extensive *ilmenite-bearing beach sands in Australia, and now in Tanzania, the separation and analysis of the mineral has become more important than ever. This is particularly because ilmenite has now become the principal source of rutile, an important product in the manufacture of pigments and ceramic materials. Ion exchange separation using a mixture of HCI and HF is described in the literature. The method has serious limitations especially when the use of glassware cannot be avoided. The author has successfully applied exclusively HCI solution for the anion exchange separation. The mineral was first brought in solution …
The Kunduchi Mangrove Basin, Alison Mccusker
The Kunduchi Mangrove Basin, Alison Mccusker
Tanzania Journal of Science
The pattern of tidal submergence and exposure in the Kunduchi mangrove basin is determined by contour mapping and by relating the contours to published tide predictions. Salinity of the creek effluent is measured at spring and neap tides in both wet and dry seasons. The vegetation of the basin, up to the highest high water level, is described briefly.