Despite Lolgorien being one of the most active gold mining areas in Kenya, it is one of the most ... more Despite Lolgorien being one of the most active gold mining areas in Kenya, it is one of the most geologically understudied areas. To the best knowledge of the authors, Lolgorien geological map was last updated in the 1940s. Current technologies such as remote sensing allow new structural features such as faults to be easily identified. In this regard, this study employed remote sensed data to map structural features found in and around Lolgorien Subcounty, Narok, Kenya. This was done to identify any new structural features that might have been missed in the past. Shuttle Radar 152 Topography Mission Digital Elevation Model (SRTM-DEM) image was downloaded and analysed using hillshade technique. From this analysis, the research identified new structural features which were not included in the current geological map but exist on the ground. One such structural feature (fault) is located approximately at 9866237, 703601 (Universal Transverse Mercator, UTM coordinates) and trends in NW–S...
The largest segment of the Neoproterozoic Mozambique orogenic belt in Kenya occurs east of the no... more The largest segment of the Neoproterozoic Mozambique orogenic belt in Kenya occurs east of the north-south oriented rift system. Geological investigations carried out in the country during the last few decades have revealed the complexity of the geology, structures and tectonics of the Mozambique Belt in the region. Important high-grade tectonothermal events in the belt took place between ca. 845
Nairobi City is underlain by volcanic materials that resulted from the formation of the rift vall... more Nairobi City is underlain by volcanic materials that resulted from the formation of the rift valley. Some of the challenges that face design of structures in the city include: the need to develop structures in areas with poor site conditions; distress in structures that could be related to foundation conditions; encounter of unexpected subsoil conditions even after carrying out some geotechnical investigations, and; development of defects related to adjacent deep excavation. The objectives of this study were: to investigate the qualitative and quantitative properties of subsurface materials, to establish the engineering property variations and to provide properties that represent the best estimates. Information available for this study included; Atterberg limits, grading, consolidation, swell and collapse, triaxial shear and direct shear, point load and unconfined compressive strength. Failure investigation and resistivity survey were carried out to fill the gaps in the available in...
Nairobi City is mainly underlain by pyroclastic volcanic rocks that were deposited during the for... more Nairobi City is mainly underlain by pyroclastic volcanic rocks that were deposited during the formation of the East African Rift Valley. Some of the volcanic rocks were deposited in aqueous conditions over a long period of time and are intercalated with lacustrine sediments. River valleys and other depressions that existed during the periods of intermittent inactivity were filled with alluvium and clays. At building sites, the alluvium, clays as well as decomposed volcanic tuffs are found to have variable thicknesses and sensitive to moisture. The objectives of this research were: to identify localities covered by the sensitive and variable soils; to determine the geotechnical properties of the soils and to examine the methods and processes that make for a successful construction program. Geotechnical test results and reports from fifty seven sites underlain by these soils were analysed. The results show that structures with defects exist side by side with those in sound condition. ...
Explosive volcanic eruptions affect climate by injecting gases and aerosol particles into the tro... more Explosive volcanic eruptions affect climate by injecting gases and aerosol particles into the troposphere and stratosphere. Only if the eruption cloud is rich in SO2 will the eruption produce a long -lived aerosol cloud, in response to the sulfate aerosols that form over the next few weeks. The eruption of OlDoinyo Lengai Tanzania, July 2007 and March 2008, injected pollutants into the atmosphere with potential impacts on the air quality and climate over East Africa. This work simulated the spatial and temporal distribution of the volcanic gases and particulate matter emitted after the eruption. The Hybrid Single -Particle Lagrangian Integrated Trajectory (HYSPLIT) model, which is a complete system for computing simple air parcel trajectories to complex dispersion and deposition simulations, was used for the analysis . The dispersion of pollutant was calculated by assuming either puff or particle dispersion. The results indicated that the effluents were largely spread and eventually...
In the Voi Area of Southern Kenya, the granulite facies rocks of the Taita Hills and the Tsavo Ea... more In the Voi Area of Southern Kenya, the granulite facies rocks of the Taita Hills and the Tsavo East National Park (Galana River) can be divided into three structural domains: The Galana-East unit consists of an intercalation of flat lying metapelites and marbles of continental margin origin. These metasediments can be traced further east to the Umba Steppe (Between Mombasa and Tanga). Galana-West consists of a N-S oriented wrench fault zone with vertical foliation planes and horizontal stretching lineation. Numerous shear sense indicators always show sinistral shear sense. Amphibolites of MORB affinity are involved in this wrench fault zone. To the west, this zone is bordered by calc-alkaline metatonalites of the Sagala Hills. The westernmost unit consists of the Taita Hills. They form an imbricated pile of southwestward thrusted nappe sheets containing metapelites, marbles, and ultramafics. The Taita Hills may be explained as part of an accretionary wedge. Southwestward nappe thrus...
Two different Pan-African tectono-metamorphic events are recognised in the Taita Hill Tsavo East ... more Two different Pan-African tectono-metamorphic events are recognised in the Taita Hill Tsavo East National Park/Galana river area, SE-Kenya (Mozambique belt) based on petrographic and geothermobarometric evidence. Structurally, this area can be subdivided into four units: (1) the easternmost part of the basement along the Galana river is characterized by subhorizontal slightly to the west and east dipping foliation planes. Migmatic paragneisses with intercalated marbles, calcsilicates and metapelites and bands of amphibolites are the dominant rock type. (2) The western part of the Galana river within the Tsavo East National Park is a ca. 25km wide shear zone with subvertical foliation planes. The eastern part shows similar rocks as observed in unit 1, while towards west, metasedimentary units become rare and the main rock types are tonalitic gneisses with intercalated amphibolites. (3) A 10km wide zone (Sagala Hills zone) between the strike slip zone (unit 2) and the Taita Hills (unit 4) is developed. This zone is characterized by elongated and folded felsic migmatic amphibole and garnet bearing orthogneiss bodies with intercalated bands of mafic rocks. (4) The Taita Hills are a slightly to the N dipping nappe stack. The main rock type in the Taita Hills are amphibole–biotite–plagioclase–quartz±garnet±clinopyroxene±scapolite bearing migmatic gneisses with mafic bands. In the southern part, metapelites, marbles and some amphibolites are common.Although the geological structures are different in units 1 and 2, the calculated PT conditions are similar with peak PT of 760–820°C and 7.5–9.5kbar. Temperatures in unit 3 (Sagalla Hills zone) and unit 4 (Taita Hills) are slightly higher ca. 760–840°C, but pressure is significantly higher, ranging from 10 to 12kbar. Sillimanite growth around kyanite, garnet zonation pattern, mineral reaction textures, and PT calculations constrain a “clock-wise” PT-path with near isobaric cooling following the peak of metamorphism. The different PT conditions, tectonic setting, and a different age of metamorphism are evidence that units 1 and 2 (Galana river) belong to a different tectono-metamorphic event than unit 3 (Sagala Hills zone) and 4 (Taita Hills). The major shear zone (unit 2) marks a tectonic suture dividing the two different tectono-metamorphic domains. It is also likely that it played an important role during exhumation of the granulite facies rocks from units 3 and 4.
Kenya is in a unique environmental setting by virtue of its geographical location, range of altit... more Kenya is in a unique environmental setting by virtue of its geographical location, range of altitudes and perhaps most importantly, the Great Rift System that traverses it. The country displays virtually every facet of environmental geological phenonmena seismicity, volcanism, mass-...
A micaceous mineral (MicaM) available locally in Kenya was utilized as an inexpensive and effecti... more A micaceous mineral (MicaM) available locally in Kenya was utilized as an inexpensive and effective adsorbent for the removal of Cu2+ ions from aqueous solution. The effects of contact time, pH, temperature, adsorbate and adsorbent concentrations, and the concentration of electrolyte on the removal of Cu2+ ions were studied. Maximum removal of Cu2+ ions occurred over the pH range 4.0–7.0. The adsorption of Cu2+ ions increased with an increase in the dose ratio of mineral to Cu2+ ion concentration and decreased with adsorbent particle size. Isotherm analysis of the adsorption data obtained at 25°C showed that the adsorption of Cu2+ ions on MicaM followed both the Langmuir and Freundlich isotherms. The uptake of Cu2+ ions increased on increasing the pH of the solution from 1.5 to 7.0 as well as on increasing the temperature from 25°C to 60°C. An adsorption capacity of 0.850 g/g was achieved for MicaM towards the Cu2+ ion. This study has demonstrated that locally abundant micaceous min...
Kirtlandia, a publication of The Cleveland Museum of Natural History, is named in honor of Jared ... more Kirtlandia, a publication of The Cleveland Museum of Natural History, is named in honor of Jared Potter Kirtland, a noted nineteenth-century naturalist who lived in the Cleveland, Ohio area. It began publication in 1967 and is a continuation of the earlier series Scientific Publications volumes 1 to 10 (1928–1950), and new series volumes 1 to 4 (1962–1965).
The largest segment of the Neoproterozoic Mozambique belt in Kenya occurs east of the north-south... more The largest segment of the Neoproterozoic Mozambique belt in Kenya occurs east of the north-south oriented Rift system. Geological works carried out in the country during the last few decades have progressively revealed the complexity of the geology, structures and tectonics of the Mozambique belt in the region. Important high grade tectono-thermal events in the belt took place between about 845 and 715 Ma. The tectonothermal events attained P/T conditions of 5.5 - 7.1 kbars and 500 - 750o C. The subsequent cooling and uplift of the basement has been traced by K-Ar dates on biotites, which range between 528 and 438 Ma. New lithological units established in the last two decades include widespread granitoid, anorthositic, gabbroic to ultramafic intrusions and limited andesitic volcanics in the central region of this eastern segment of the Mozambique belt (EMBS). Previously the geology of this central region had been considered to consist predominantly of pelitic and semi-pelitic schis...
Despite Lolgorien being one of the most active gold mining areas in Kenya, it is one of the most ... more Despite Lolgorien being one of the most active gold mining areas in Kenya, it is one of the most geologically understudied areas. To the best knowledge of the authors, Lolgorien geological map was last updated in the 1940s. Current technologies such as remote sensing allow new structural features such as faults to be easily identified. In this regard, this study employed remote sensed data to map structural features found in and around Lolgorien Subcounty, Narok, Kenya. This was done to identify any new structural features that might have been missed in the past. Shuttle Radar 152 Topography Mission Digital Elevation Model (SRTM-DEM) image was downloaded and analysed using hillshade technique. From this analysis, the research identified new structural features which were not included in the current geological map but exist on the ground. One such structural feature (fault) is located approximately at 9866237, 703601 (Universal Transverse Mercator, UTM coordinates) and trends in NW–S...
The largest segment of the Neoproterozoic Mozambique orogenic belt in Kenya occurs east of the no... more The largest segment of the Neoproterozoic Mozambique orogenic belt in Kenya occurs east of the north-south oriented rift system. Geological investigations carried out in the country during the last few decades have revealed the complexity of the geology, structures and tectonics of the Mozambique Belt in the region. Important high-grade tectonothermal events in the belt took place between ca. 845
Nairobi City is underlain by volcanic materials that resulted from the formation of the rift vall... more Nairobi City is underlain by volcanic materials that resulted from the formation of the rift valley. Some of the challenges that face design of structures in the city include: the need to develop structures in areas with poor site conditions; distress in structures that could be related to foundation conditions; encounter of unexpected subsoil conditions even after carrying out some geotechnical investigations, and; development of defects related to adjacent deep excavation. The objectives of this study were: to investigate the qualitative and quantitative properties of subsurface materials, to establish the engineering property variations and to provide properties that represent the best estimates. Information available for this study included; Atterberg limits, grading, consolidation, swell and collapse, triaxial shear and direct shear, point load and unconfined compressive strength. Failure investigation and resistivity survey were carried out to fill the gaps in the available in...
Nairobi City is mainly underlain by pyroclastic volcanic rocks that were deposited during the for... more Nairobi City is mainly underlain by pyroclastic volcanic rocks that were deposited during the formation of the East African Rift Valley. Some of the volcanic rocks were deposited in aqueous conditions over a long period of time and are intercalated with lacustrine sediments. River valleys and other depressions that existed during the periods of intermittent inactivity were filled with alluvium and clays. At building sites, the alluvium, clays as well as decomposed volcanic tuffs are found to have variable thicknesses and sensitive to moisture. The objectives of this research were: to identify localities covered by the sensitive and variable soils; to determine the geotechnical properties of the soils and to examine the methods and processes that make for a successful construction program. Geotechnical test results and reports from fifty seven sites underlain by these soils were analysed. The results show that structures with defects exist side by side with those in sound condition. ...
Explosive volcanic eruptions affect climate by injecting gases and aerosol particles into the tro... more Explosive volcanic eruptions affect climate by injecting gases and aerosol particles into the troposphere and stratosphere. Only if the eruption cloud is rich in SO2 will the eruption produce a long -lived aerosol cloud, in response to the sulfate aerosols that form over the next few weeks. The eruption of OlDoinyo Lengai Tanzania, July 2007 and March 2008, injected pollutants into the atmosphere with potential impacts on the air quality and climate over East Africa. This work simulated the spatial and temporal distribution of the volcanic gases and particulate matter emitted after the eruption. The Hybrid Single -Particle Lagrangian Integrated Trajectory (HYSPLIT) model, which is a complete system for computing simple air parcel trajectories to complex dispersion and deposition simulations, was used for the analysis . The dispersion of pollutant was calculated by assuming either puff or particle dispersion. The results indicated that the effluents were largely spread and eventually...
In the Voi Area of Southern Kenya, the granulite facies rocks of the Taita Hills and the Tsavo Ea... more In the Voi Area of Southern Kenya, the granulite facies rocks of the Taita Hills and the Tsavo East National Park (Galana River) can be divided into three structural domains: The Galana-East unit consists of an intercalation of flat lying metapelites and marbles of continental margin origin. These metasediments can be traced further east to the Umba Steppe (Between Mombasa and Tanga). Galana-West consists of a N-S oriented wrench fault zone with vertical foliation planes and horizontal stretching lineation. Numerous shear sense indicators always show sinistral shear sense. Amphibolites of MORB affinity are involved in this wrench fault zone. To the west, this zone is bordered by calc-alkaline metatonalites of the Sagala Hills. The westernmost unit consists of the Taita Hills. They form an imbricated pile of southwestward thrusted nappe sheets containing metapelites, marbles, and ultramafics. The Taita Hills may be explained as part of an accretionary wedge. Southwestward nappe thrus...
Two different Pan-African tectono-metamorphic events are recognised in the Taita Hill Tsavo East ... more Two different Pan-African tectono-metamorphic events are recognised in the Taita Hill Tsavo East National Park/Galana river area, SE-Kenya (Mozambique belt) based on petrographic and geothermobarometric evidence. Structurally, this area can be subdivided into four units: (1) the easternmost part of the basement along the Galana river is characterized by subhorizontal slightly to the west and east dipping foliation planes. Migmatic paragneisses with intercalated marbles, calcsilicates and metapelites and bands of amphibolites are the dominant rock type. (2) The western part of the Galana river within the Tsavo East National Park is a ca. 25km wide shear zone with subvertical foliation planes. The eastern part shows similar rocks as observed in unit 1, while towards west, metasedimentary units become rare and the main rock types are tonalitic gneisses with intercalated amphibolites. (3) A 10km wide zone (Sagala Hills zone) between the strike slip zone (unit 2) and the Taita Hills (unit 4) is developed. This zone is characterized by elongated and folded felsic migmatic amphibole and garnet bearing orthogneiss bodies with intercalated bands of mafic rocks. (4) The Taita Hills are a slightly to the N dipping nappe stack. The main rock type in the Taita Hills are amphibole–biotite–plagioclase–quartz±garnet±clinopyroxene±scapolite bearing migmatic gneisses with mafic bands. In the southern part, metapelites, marbles and some amphibolites are common.Although the geological structures are different in units 1 and 2, the calculated PT conditions are similar with peak PT of 760–820°C and 7.5–9.5kbar. Temperatures in unit 3 (Sagalla Hills zone) and unit 4 (Taita Hills) are slightly higher ca. 760–840°C, but pressure is significantly higher, ranging from 10 to 12kbar. Sillimanite growth around kyanite, garnet zonation pattern, mineral reaction textures, and PT calculations constrain a “clock-wise” PT-path with near isobaric cooling following the peak of metamorphism. The different PT conditions, tectonic setting, and a different age of metamorphism are evidence that units 1 and 2 (Galana river) belong to a different tectono-metamorphic event than unit 3 (Sagala Hills zone) and 4 (Taita Hills). The major shear zone (unit 2) marks a tectonic suture dividing the two different tectono-metamorphic domains. It is also likely that it played an important role during exhumation of the granulite facies rocks from units 3 and 4.
Kenya is in a unique environmental setting by virtue of its geographical location, range of altit... more Kenya is in a unique environmental setting by virtue of its geographical location, range of altitudes and perhaps most importantly, the Great Rift System that traverses it. The country displays virtually every facet of environmental geological phenonmena seismicity, volcanism, mass-...
A micaceous mineral (MicaM) available locally in Kenya was utilized as an inexpensive and effecti... more A micaceous mineral (MicaM) available locally in Kenya was utilized as an inexpensive and effective adsorbent for the removal of Cu2+ ions from aqueous solution. The effects of contact time, pH, temperature, adsorbate and adsorbent concentrations, and the concentration of electrolyte on the removal of Cu2+ ions were studied. Maximum removal of Cu2+ ions occurred over the pH range 4.0–7.0. The adsorption of Cu2+ ions increased with an increase in the dose ratio of mineral to Cu2+ ion concentration and decreased with adsorbent particle size. Isotherm analysis of the adsorption data obtained at 25°C showed that the adsorption of Cu2+ ions on MicaM followed both the Langmuir and Freundlich isotherms. The uptake of Cu2+ ions increased on increasing the pH of the solution from 1.5 to 7.0 as well as on increasing the temperature from 25°C to 60°C. An adsorption capacity of 0.850 g/g was achieved for MicaM towards the Cu2+ ion. This study has demonstrated that locally abundant micaceous min...
Kirtlandia, a publication of The Cleveland Museum of Natural History, is named in honor of Jared ... more Kirtlandia, a publication of The Cleveland Museum of Natural History, is named in honor of Jared Potter Kirtland, a noted nineteenth-century naturalist who lived in the Cleveland, Ohio area. It began publication in 1967 and is a continuation of the earlier series Scientific Publications volumes 1 to 10 (1928–1950), and new series volumes 1 to 4 (1962–1965).
The largest segment of the Neoproterozoic Mozambique belt in Kenya occurs east of the north-south... more The largest segment of the Neoproterozoic Mozambique belt in Kenya occurs east of the north-south oriented Rift system. Geological works carried out in the country during the last few decades have progressively revealed the complexity of the geology, structures and tectonics of the Mozambique belt in the region. Important high grade tectono-thermal events in the belt took place between about 845 and 715 Ma. The tectonothermal events attained P/T conditions of 5.5 - 7.1 kbars and 500 - 750o C. The subsequent cooling and uplift of the basement has been traced by K-Ar dates on biotites, which range between 528 and 438 Ma. New lithological units established in the last two decades include widespread granitoid, anorthositic, gabbroic to ultramafic intrusions and limited andesitic volcanics in the central region of this eastern segment of the Mozambique belt (EMBS). Previously the geology of this central region had been considered to consist predominantly of pelitic and semi-pelitic schis...
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