Bio

Publications


2013

Nyamai, C.M. in Feneyrol J., GOFMLGPISGDAE.  2013.  New aspects and perspectives on Tsavorite Deposits. Ore Geology Reviews 53 (2013) pp 1–25.. Ore Geology Reviews . 53 (2013):pp1–25.. Abstractsciencedirect

ABSTRACT

Tsavorite, the vanadian variety of green grossular, is a high value economic gemstone. It is hosted exclusively in the metasedimentary formations from the Neoproterozoic Metamorphic Mozambique Belt. The deposits are mined in Kenya, Tanzania and Madagascar and other occurrences are located in Pakistan and East Antarctica.

They are located within metasomatized graphitic rocks such as graphitic gneiss and calc-silicates, intercalated with meta-evaporites. Tsavorite is found as primary deposits either in nodule (type I) or in quartz vein (type II), and in placers (type III). The primary mineralizations (types I and II) are controlled by lithostratigraphy and/or structure. For the African occurrences, the protoliths of the host-rocks were deposited at the beginning of the Neoproterozoic within a marine coastal sabkha environment, located at the margin of the Congo–Kalahari cratons in the Mozambique Ocean. During the East African–Antarctican Orogeny, the rocks underwent high amphibolite to granulite facies metamorphism and the formation of tsavorite deposits occurred between 650 and 550 Ma. The nodules of tsavorite were formed during prograde metamorphism, calcium coming from sulphates and carbonates, whereas alumina, silicates, vanadium and chromium probably came from clays and chlorite. The veins were formed during the deformation of the metasedimentary platform units which experienced shearing, leading to the formation of fault-filled veins.

Metasomatism developed during retrograde metamorphism. The metasedimentary sequences are characterized by the presence of evaporitic minerals such as gypsum and anhydrite, and scapolite. Evaporites are essential as they provide calcium and permit the mobilization of all the chemical elements for tsavorite formation. The H2S–S8 metamorphic fluids characterized in primary fluid inclusions of tsavorites and the δ11B values of coeval dravite confirm the evaporitic origin of the fluids. The V2O3 and Cr2O3 contents of tsavorite range respectively from 0.05 to 7.5 wt.%, while their δ18O values are in the range of 9.5–21.1‰.

The genetic model proposed for tsavorite is metamorphic, based on chemical reactions developed between an initial assemblage composed of gypsum and anhydrite, carbonates and organic matter deposited in a sabkha-like sedimentary basin.

2010

Nyamai, C.M., Ngecu WM, Kianji G.  2010.  SGL 308: Introduction to Geological Mapping (Lecture series).

2009

MUNYAO, DRNYAMAICHRISTOPHER.  2009.  Nyamai, C.M., Mingala, O.J., and Phillips, C. 2009. Sub-regional/Regional Organizations and Popular Social Engineering in Africa: Empowering young people and the spirit of volunteerism (civic service). In: A. Amuwo, H. Pul and I.O. Adadevoh (Eds.) Civil S. Proceedings of the XIIth International Anatomical Congress: London 764 A.. Abstract

One of the critical issues for Community Development, Civil Society action and Governance anywhere and specifically in Africa is to create leaders at the fastest possible rate, at all levels of the society/ community. Such levels of leadership revolve round - skilled, ethical, effective and unifying leadership. Young people are most eager to play a leadership role in these efforts. The values/ benefits of the African young people involvement in Civil Society in the African states will bring energy, catalyze other group members to rethink their priorities, commitment and remove invisible barriers that have kept them from moving forward. Typically and traditionally in many cultures, young people have been excluded from efforts to rebuild their communities. This marginalization of our youth not only harms them and endangers our future, but it also cheats the world of a valuable resource. If we are to function effectively as local and even global communities then we must incorporate all significant voices. This paper argues that an enduring and positive community renewal is possible only if all members are involved and feel a sense of ownership. On the other hand, the spirit of volunteerism by young people helps to create a stable and cohesive society and as a result add value to the services that governments provide. Voluntary action creates bonds of trust and encourages cooperation; in other words it creates social capital. Volunteerism draws people of different ethnic origins, religion and economic status. This compositional aspect enhances social harmony. Voluntary participation in public affairs can also help to create a politically literate public, which is important for the preservation of democratic principles. Volunteer effort is essential to Civil Society action as a way that would enhance community policing and conflict resolution. Service For Peace (SFP) Kenya Chapter as an organization, through its young people empowerment program has the aim to integrate service learning and volunteerism in the processes of capacity development/ building, creating appropriate awareness, dissemination and networking of the youth in the sub-regional and region areas. The Kenyan Chapter serves as a knowledge resource base for periodic value-based training programs on volunteerism.

2008

MUNYAO, DRNYAMAICHRISTOPHER.  2008.  SGL 308: Introduction to Geological Mapping, Lecture series. Proceedings of the XIIth International Anatomical Congress: London 764 A.. , Nairobi: Nairobi University Press. Abstract

One of the critical issues for Community Development, Civil Society action and Governance anywhere and specifically in Africa is to create leaders at the fastest possible rate, at all levels of the society/ community. Such levels of leadership revolve round - skilled, ethical, effective and unifying leadership. Young people are most eager to play a leadership role in these efforts. The values/ benefits of the African young people involvement in Civil Society in the African states will bring energy, catalyze other group members to rethink their priorities, commitment and remove invisible barriers that have kept them from moving forward. Typically and traditionally in many cultures, young people have been excluded from efforts to rebuild their communities. This marginalization of our youth not only harms them and endangers our future, but it also cheats the world of a valuable resource. If we are to function effectively as local and even global communities then we must incorporate all significant voices. This paper argues that an enduring and positive community renewal is possible only if all members are involved and feel a sense of ownership. On the other hand, the spirit of volunteerism by young people helps to create a stable and cohesive society and as a result add value to the services that governments provide. Voluntary action creates bonds of trust and encourages cooperation; in other words it creates social capital. Volunteerism draws people of different ethnic origins, religion and economic status. This compositional aspect enhances social harmony. Voluntary participation in public affairs can also help to create a politically literate public, which is important for the preservation of democratic principles. Volunteer effort is essential to Civil Society action as a way that would enhance community policing and conflict resolution. Service For Peace (SFP) Kenya Chapter as an organization, through its young people empowerment program has the aim to integrate service learning and volunteerism in the processes of capacity development/ building, creating appropriate awareness, dissemination and networking of the youth in the sub-regional and region areas. The Kenyan Chapter serves as a knowledge resource base for periodic value-based training programs on volunteerism.

2007

MUNYAO, DRNYAMAICHRISTOPHER, Ambrose SH, MATHU ELIUDM, Williams MAJ.  2007.  GEOLOGY, GEOCHEMISTRY, AND STRATIGRAPHY OF THE LEMUDONG’O FORMATION, KENYA RIFT VALLEY, December. Kitlandia Vol.56:53-64. : The Cleveland Museum of Natural History Abstract

ABSTRACT
The Lemudong’o Formation is defined here as part of a late Miocene to Late Pleistocene sequence of stratified lavas, air-fall and waterlain tuffs, lacustrine, alluvial, and fluvial sediments, and paleosols, that crop out over an approximately 25*50 km area on the western margin of the southern Kenyan Rift Valley, approximately 100 km west of Nairobi. The study area is deeply incised by three major permanent river systems that expose sediments of three late Neogene lake basins. The Lemudong’o Formation comprises deposits of the second paleolake basin, which formed during the late Miocene. Stratigraphic sections in several localities are described and correlated in this report, the Lemudong’o Formation is defined, and a basin sedimentary history and environmental reconstruction is proposed.

The Lemudong’o Formation has three main phases of sedimentation with a total thickness of 135 m. Phase 1 is represented by predominantly lacustrine and lake-margin siltstones, mudstones,and sandstones. Phase 2 comprises paleosols in the basin center, and fluvial and alluvial sediments on the eastern basin margin. Phase 3 comprises mainly waterlain tuffs and silts, capped by a welded tuff. Phase 2 may reflect a more arid climate, or a lower basin-overflow elevation. Four tuffs in upper phase-1 mudstones in Lemudong’o Gorge are dated to 6.12 – 6.08 Ma. The main fossil-bearing horizons at Lemudong’o Gorge Locality 1 lie between, and immediately above, the dated tuffs. Fossils are associated with beach and/or deltaic sands and fine gravels, and silty and sandy claystones representative of an intermittently flooded lake margin

MUNYAO, DRNYAMAICHRISTOPHER.  2007.  Nyamai C.M. et al. 2007. The Paleoecology and Paleogeographic Context of Lemudong. Kirtlandia Vol. 56:38-52. : The Cleveland Museum of Natural History

2005

MUNYAO, DRNYAMAICHRISTOPHER.  2005.  E.M Mathu and C.M Nyamai - Recent Findings of the geology, tectonics and economic resources of the Neoproterozoic Mozambique Belt in East African and the way forward. - 2005. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History

2004

MUNYAO, DRNYAMAICHRISTOPHER.  2004.  Ngecu, W.M., Nyamai, C.M. and Erima, G. 2004. The extent and Significance of mass-movements in Eastern Africa: Case studies of some major landslides in Uganda and Kenya. Environmental Geology, Vol. 46, pp 1123-1133.. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History
MUNYAO, DRNYAMAICHRISTOPHER.  2004.  Nyamai, C.M. 2004. SGL 201: Principles of Mineralogy, Lecture series. Nairobi University Press, pp 119.. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History

2003

MUNYAO, DRNYAMAICHRISTOPHER.  2003.  Nyamai, C.M., Mathu, E.M., Wallbrecher, E. and Opiyo-Akech. 2003. A reappraisal of the geology, structures and tectonics of the Mozambique Belt in Kenya, east of the rift system. African Journal of Science and Technology (AJST), Vol. 4, No.2, pp 51-71. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History
MUNYAO, DRNYAMAICHRISTOPHER.  2003.  Nyamai, C.M. 2003. SGL 101: Materials of the Earth, Lecture series. Nairobi University Press, pp 110.. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History

2002

Nyamai, CM, Surapunt S, Itagaki K.  2002.  Phase relations in the Cu2S-FeS-ZnS and Cu2S-PbS-ZnS Ternary Systems at 1473 K: Extraction of Zinc from sulfide ore using liquid copper as a reagent. AbstractPhase relations in the Cu2S-FeS-ZnS and Cu2S-PbS-ZnS Ternary Systems at 1473 K: Extraction of Zinc from sulfide ore using liquid

The use of liquid copper as a medium for zinc extraction has been used in the Warner Process as a method of processing zinc-lead sulphide ore. The recovery of zinc metal is based on the reaction: ZnS(s) + 2Cu(l) = Zn(g) + Cu2S(l) In this method, thermodynamic and phase equilibria investigations of the Cu2S-FeS-ZnS and Cu2S-PbS-ZnS systems are of importance and form the basis for the liquid sulphide phase which appears as a product and is used as a solvent in the Warner Process. Phase relations in the Cu2S-FeS-ZnS and Cu2S-PbS-ZnS ternary systems were determined experimentally at 1473°K to provide a fundamental basis for the new zinc smelting process. The results show that the solid solubility of ZnS in the two systems is very small (2 wt% to 3 wt% ZnS in FeS, 4 wt% ZnS in Cu2S for the Cu2S-FeS-ZnS system; less than 0.5 wt% ZnS in both PbS and Cu2S for the Cu2S-PbS-ZnS system). The Raoultian Activity Coefficient of ZnS in the liquid mixtures and the vapour pressure of zinc over the matte in both systems is relatively large (γ° = 7.7 - 15.8, Pzn(atm) = 0.088 - 1.026 for the Cu2S-FeS-ZnS system; γ° = 8.9 - 12.9, PZn(atm) = 0.075 - 0.214 for the Cu2S-PbS-ZnS system). On the FeS-ZnS join, the only phases detected are FeS and iron-rich sphalerite (Zn, Fe)S. The binary join mixture occurs at about 92 wt% FeS-8 wt% ZnS at 1473°K. Electron microprobe examination of the quenched samples indicate about 47 wt% to 48 wt% FeS in sphalerite and about 2 wt% to 3 wt% ZnS in the iron sulphide phase. On the Cu2S-ZnS join, microprobe analysis reveals that the maximum solubility is 4 wt% Zn in liquid Cu2S and 3.6 wt% Cu in solid ZnS. In the Cu2S-PbS-ZnS ternary system, microprobe analysis of the quenched samples indicate on average, 5 wt% ZnS in the liquid phase region. The only phases detected on the PbS- ZnS join are ZnS and PbS. The eutectic phase contains, on average, 13 wt% ZnS. The phase relationships, very low solid solubilities of zinc sulphide in the liquid mixtures of both Cu2S-FeS-ZnS and Cu2S-PbS-ZnS systems, coupled with the high Raoultian Activity Coefficient of ZnS as well as the high vapour pressure of zinc over matte all favour the partitioning of zinc metal into the vapour phase. This new process is cost effective and bypasses the expensive and tedious conventional technique of zinc production involving oxidation of the sulphide ore by roasting followed by a reduction process to extract the zinc. The results indicate that a new zinc smelting technology using the Warner Process would be more efficient and preferable over the traditional methods of zinc extraction.

MUNYAO, DRNYAMAICHRISTOPHER.  2002.  Nyamai, C.M 2002. University-Industry Collaboration: a strategy for Rapid Development. In: L. Vasconcelos (Ed.) Regional workshop on Tertiary Sector Geoscience Education in Southern Africa. Building Regional Networks on local expertise. University Press o. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History
MUNYAO, DRNYAMAICHRISTOPHER.  2002.  Mathu, E.M., Nyamai, C.M. and W.M. Ngecu. 2002. Environmental degradation through quarrying: a case study in Tala-Kangaundo area, central Kenya. Africa Geoscience Review, Vol. 9, No. 4, pp. 385-395.. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History
MUNYAO, DRNYAMAICHRISTOPHER.  2002.  Phase relations in the Cu2S-FeS-ZnS and Cu2S-PbS-ZnS Ternary Systems at 1473 K: Extraction of Zinc from sulfide ore using liquid copper as a reagent. Canadian Mining and Metallurgical Bulletin (CIM) Vol, 95 pp. 129-132.. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History

2001

Nyamai, CM, Mathu EM, Wallbrecher E, Opiyo-Akech..  2001.  A Reappraisal of the Geology, Structures and Tectonics of the Mozambique Belt in Kenya East of the Rift System. Gondwana Research. Vol. 4(No.4)CLICK HERE FOR THE ABSTRACT
MUNYAO, DRNYAMAICHRISTOPHER, MATHU PROFMUTHUMBIELIUD.  2001.  New fossilferous sites in Gatarakwa, central Kenya : Their geological setting, stratigraphy, and contribution to palaeontological research in East Africa. Journal of The Geoscience Society of Camerron, Vo. 1, No.1A, pp. 80-81. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History
MUNYAO, DRNYAMAICHRISTOPHER.  2001.  A comparison of the uncomphagrite and turjaite mineralogy (phlogopite, melilite, etc.) of the south Nyanza district, western Kenya with similar rock complexes in Asia, Australia and America. Gondwana Research, Vol. 4, No.4, p.719. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History

2000

Nyamai, CM, Njenga FG.  2000.  Post-traumatic stress disorder: Case report. AbstractPost-traumatic stress disorder: Case report

Following exposure to a major traumatic event like the August seventh 1998 Nairobi bomb blast various reactions occur, some of which result in stress-related psychiatric disorders. We have described one such case, and used it to illustrate the salient features of posttraumatic stress disorder. We have outlined the diagnostic categories of the post-traumatic disorders and discussed the different treatment modalities applicable

MUNYAO, DRNYAMAICHRISTOPHER, OPIYO PROFAKECHNOBERT.  2000.  Structures, Metamorphism and Geochronology of the Mozambique belt metamorphic and intrusive rocks from Matuu-Masinga area, central Kenya. African Journal of Science and Technology (AJST), Science and Engineering Series, Vol. 1, No.1, pp 47-55.. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History
MUNYAO, DRNYAMAICHRISTOPHER.  2000.  Petrography, mineral chemistry and thermobarometry of the Neoporoterozoic Mozambique belt rocks of Matuu-Masinga area, central Kenya. Proceedings of the International seminar UNESCO-IUGS-IGCP-368, Geological Survey of India Special Publication No. 57,pp.2. Ist intern. Geol. Field conf. on Oban-Odudu Massif, S.E Nigeria Calabar Univer., Scientific Programme and Abstracts pp17-18. : The Cleveland Museum of Natural History

1999

MUNYAO, DRNYAMAICHRISTOPHER, OPIYO PROFAKECHNOBERT.  1999.  Geochemistry and Tectonomagmatic affinities of the Mozambique belt intrusive rocks in Matuu-Masinga area, central Kenya. Gondwana Research, Vol.2, pp. 387-399.. Ph.D Degree Thesis, University of Nairobi Kenya. : The Cleveland Museum of Natural History
MUNYAO, DRNYAMAICHRISTOPHER.  1999.  Crustal evolution of the Neoproterozoic Mozambique belt rocks in Matuu-Masinga area, central Kenya: Implications to their tectonic setting and potential mineralization.. Ph.D Degree Thesis, University of Nairobi Kenya. : The Cleveland Museum of Natural History

1995

Surapunt, S, Nyamai CM, Hino M, Itagaki K.  1995.   Phase relations and Distributions of minor elements in the Cu-Zn-S, Cu- Fe-S and Cu-Pb-S Systems at 1473K. . Metallurgical Review of MMIJ. 12(2):84-97.

1993

Gaciri, SJ, Altherr R, Nyamai CM, Mathu EM.  1993.  Distribution of elements in mineral pairs from Mozambique belt rocks of Matuu a rea, central Kenya. Geology for Sustainable Development. :57-62., Nairobi - Kenya: UNEP/UNESCO
Nyamai, CM, Mathu EM, Ngecu WM.  1993.  A review of the geology of the Mozambique Belt in Kenya. In: Peters, J.W., Kesse, G.O. and Acquah, P.C., (Eds.). Regional trends in African Geology. :334-347., Accra, Ghana: Geological Society of Africa

1991

Mathu, EM, Ngecu WM, Nyamai CM, Mathu, E. M; Ngecu NDWM; CM;.  1991.  Proterozoic island tectonism in the Kenyan Mozambique belt east of Nairobi.
  1991.  Structures and tectonics of the Mozambique belt in Kenya. Geology for Sustainable Development. Newsletter/Bulletin 8 (IGCP Project 348)

1989

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