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The Central Kenya Peralkaline Province: Insights Into the Evolution of Peralkaline Salic Magmas
The central Kenya peralkaline province: Insights into the evolution of peralkaline salic magmas. Ray Macdonald, Bruno Scaillet To cite this version: Ray Macdonald, Bruno Scaillet. The central Kenya peralkaline province: Insights into the evolution of peralkaline salic magmas.. Lithos, Elsevier, 2006, 91, pp.1-4, 59-73. 10.1016/j.lithos.2006.03.009. hal-00077416 HAL Id: hal-00077416 https://hal-insu.archives-ouvertes.fr/hal-00077416 Submitted on 10 Jul 2006 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. The central Kenya peralkaline province: Insights into the evolution of peralkaline salic magmas R. Macdonalda, and B. Scailletb aEnvironment Centre, Lancaster University, Lancaster LA1 4YQ, UK bISTO-CNRS, 1a rue de la Férollerie, 45071 Orléans cedex 2, France Abstract The central Kenya peralkaline province comprises five young (< 1 Ma) volcanic complexes dominated by peralkaline trachytes and rhyolites. The geological and geochemical evolution of each complex is described and issues related to the development of peralkalinity in salic magmas are highlighted. The peralkaline trachytes may have formed by fractionation of basaltic magma via metaluminous trachyte and in turn generated pantellerite by the same mechanism. Comenditic rhyolites are thought to have formed by volatile-induced crustal anatexis and may themselves have been parental to pantelleritic melts by crystal fractionation. -
PROF. GEORGE OKOYE KRHODA, CBS Department of Geography and Environmental Studies University of Nairobi P.O
PROF. GEORGE OKOYE KRHODA, CBS Department of Geography and Environmental Studies University of Nairobi P.O. Box 30197, 00100 Nairobi, KENYA Tel: +254 720 204 305; +254 733 454 216; +254 20-2017213 Fax: +254 020-2017213 Email: [email protected] PROFILE Prof. George Okoye Krhoda, CBS, is Associate Professor of Geography and Environmental Studies and Vice Chairman of the Daystar University Council. He is a Hydrologist/Water Resources Management specialist and has B.Ed.(Hons), M.A and Ph.D on River Hydraulics And Water Resources Planning. Krhoda is also the Managing Director of Research on Environment and Development Planning (REDPLAN) Consultants Ltd. Until December 2006, he was the Permanent Secretary, Ministry of Environment and Natural Resources and Chairman of the Negotiation Committee on the Nile Basin Cooperative Framework, and earlier Permanent Secretary in the Ministry of Water and Irrigation where most of the water sector reforms were carried under his watch. Currently finalizing “Environmental and social impact assessment (ESIA) for Akiira One Geothermal Power Energy in Rift Valley, having completed ESIA for Mount Suswa Geothermal Energy, Formulation of Kenya’s national Groundwater Policy; National Transboundary Water Resources Policy, and Outcome Evaluation of UNDP Rwanda Environment Programme”. Recently, Prof. Krhoda has been involved in “Development of the Mau Forest Complex Investment Programme”, “Lake Naivasha Conservation and Integrated Water Resources Management (IWRM) Programme” in developing, managing and evaluating -
The Cave Exploration Group of East Africa and Volcanic Caves in Kenya
21 Int. J. Speleol., 27 B (1/4), (1998); 21-31. THE CAVE EXPLORATION GROUP OF EAST AFRICA AND VOLCANIC CAVES IN KENYA Michael Declan Kennedy ABSTRACT This paper looks at the history of the Cave Exploration Group of East Africa with special reference to the exploration of volcanic caves. It demonstrates that the group has concentrated on two main areas, the Chyulu Hills and Mt. Suswa, although other areas have also been studied. The Cave Exploration Group of East Africa has had to cope with various problems. The most important of which are related to the socio-economic condi- tions of a developing country. These problems have not prevented the group from making a valuable contribu- tion to vulcanospeleology. Keywords: Caving Club, vulcanospeleology, Kenya FORMATION OF THE CAVE EXPLORATION GROUP OF EAST AFRICA The history of cave exploration in Kenya goes back at least 5,000 years. Dr. L.S.B. Leakey found evidence of human habitation at Gamble's Cave at Elmentaita. This dated from the Upper Kenya Capsian period (5,000-10,000 b.p.) (Clarke, 1996). Various Kenyan communities used caves as refuges, burial centres, for minerals and as religious centres (Mwaniki, 1973). The first published account of caves in Kenya is Joseph Thomson's account of the Mt. Elgon caves, although he mistakenly decided that these were formed by an ancient superior civilization mining for "precious stones or possible some precious metal" (Thomson, 1885). The caves are formed by water erosion in solu- ble pyroclastics, but have been extended by mining (Bristow, 1961). Although the Cave Exploration Group of East Africa was formed during April and May 1964, its origins lie slightly earlier. -
Simon Mang'erere Onywere
Onywere Summer School 2005 Morphological Structure and the Anthropogenic Dynamics in the Lake Naivasha Drainage Basin and its Implications to Water Flows Simon Mang’erere Onywere Department of Environmental Planning and Management, Kenyatta University P.O. Box 43844 Nairobi 00100, Kenya E-mail: [email protected] Abstract Throughout its length, the Kenyan Rift Valley is characterized by Quaternary volcanoes. At Lake Naivasha drainage basin, the Eburru (2830m) and Olkaria (2434m) volcanic complexes and Kipipiri (3349m), Il Kinangop (3906m) and Longonot (2777m) volcanoes mark the terrain. Remote sensing data and field survey were used to make morphostructural maps and to determine the structural control and the land use impacts on the drainage systems in the basin. Lake Naivasha is located at the southern part of the highest part of Kenya’s Rift Valley floor in a trough marked to the south and north by Quaternary normal faults and extensional fractures striking in a N18°W direction. The structure of the rift floor influences the axial geometry and the surface process. Simiyu and Keller (2001) interpret the rift floor structure as due to thickening related to the pre-rift crustal type and modification by magmatic processes. The rift marginal escarpments of Sattima and Mau form the main watershed areas. From the marginal escarpments the Rift Valley is formed by a series of down-stepped fault scraps. These influence the nature of the soils and the rainfall regime. The drainage is also influenced by the fault trends. At the Malewa fault line for example the drainage is south-easterly influenced by the trend of the Malewa fault line (Thompson and Dodson, 1963). -
Influence of Regional Tectonics and Pre-Existing Structures on the Formation of Elliptical Calderas in the Kenyan Rift
Downloaded from http://sp.lyellcollection.org/ by guest on September 23, 2021 Influence of regional tectonics and pre-existing structures on the formation of elliptical calderas in the Kenyan Rift E. A. M. ROBERTSON1*, J. BIGGS1, K. V. CASHMAN1, M. A. FLOYD2 & C. VYE-BROWN3 1School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen’s Road, Bristol BS8 2JN, UK 2Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA 3British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK *Corresponding author (e-mail: [email protected]) Abstract: Calderas are formed by the collapse of large magma reservoirs and are commonly ellip- tical in map view. The orientation of elliptical calderas is often used as an indicator of the local stress regime; but, in some rift settings, pre-existing structural trends may also influence the orien- tation. We investigated whether either of these two mechanisms controls the orientation of calderas in the Kenyan Rift. Satellite-based mapping was used to identify the rift border faults, intra-rift faults and orientation of the calderas to measure the stress orientations and pre-existing structural trends and to determine the extensional regime at each volcano. We found that extension in north- ern Kenya is orthogonal, whereas that in southern Kenya is oblique. Elliptical calderas in northern Kenya are orientated NW–SE, aligned with pre-existing structures and perpendicular to recent rift faults. In southern Kenya, the calderas are aligned NE–SW and lie oblique to recent rift faults, but are aligned with pre-existing structures. -
Geology of the Suswa Area
--- - Report No. 97 REPUBLIC OF KENYA I MINISTRY OF ENVIRONMENT AND NATURAL RESOURCES t MINES AND GEOLOGICAL DEPARTMENTDEPARTMENT' \ GEOLOGY OF THE SUSWA AREA DEGREE SHEET 51, NW QUARTER (with coloured geological map) 1 by R.P. RANDEL, BA, FGS and R.W. JOHNSON, BSc, PhD, ARCS Geologists 1991 ~ - -- - ,~- ~ ;;I £3@ Government of Kenya, 1991 Published by the Mines & Geological Dept., P.().P.O. Box 30009, Nairobi, Kenya Produced in Kenya by the Editorial Section, Mines & Geological Dept., P.O. Box 30009, Nairobi, Kenya Printed by AMREF, P.O. Box 30125, Nairobi, Kenya I I Cataloguing-in~publicationCataloguing-in-publication data: Geology Geology of [hethe Suswa area-“RP.area/R.P. Randel and R. W. Johnson.JohRson. - Nairobi, Kenya: Rep. 97, Mines & Geological Dept. 1991 . I Bibliography: p. 38 I Coloured geological map I ~ iSBNISBN 9966-875-04-2 I I I I ' I """1 . CONTENTS Pag‘ Preface ............................................................. .'. .. Pageiii Editors‘Editors' notenote. ........................................................ .iv Abstract.Abstract ............................................................ .. v\' I. Introduction.Introduction ......................................................... .. 1 II. Previous geological work.work ............................................. .. 3 III. Physiography.Physiography ........................................................ .. 6(3 IV.I V . Summary of geology.geology ................................................. .. 9Q V. Cainozoic volcanic and associated rocks ........................... -
Republic of Kenya Nakuru County First County
REPUBLIC OF KENYA NAKURU COUNTY FIRST COUNTY INTEGRATED DEVELOPMENT PLAN (2013-2017) KENYA Towards a Globally Competitive and Prosperous Nation SEPTEMBER 2013 COUNTY VISION AND MISSION VISION A secure, cohesive and industrialized County MISSION To formulate citizen-oriented policies, promote sustainable socio-economic and technological development TABLE OF CONTENT COUNTY VISION AND MISSION ............................................................................. 1 LIST OF TABLES AND MAPS ................................................................................... 5 ABBREVIATIONS AND ACRONYMS ....................................................................... 7 FOREWORD ............................................................................................................... 10 ACKNOWLEDGEMENTS ........................................................................................ 12 EXECUTIVE SUMMARY.......................................................................................... 14 CHAPTER ONE: COUNTY BACKGROUND INFORMATION ......................... 18 1.0 INTRODUCTION ................................................................................................. 18 1.1 POSITION AND SIZE ........................................................................................... 19 1.2 PHYSIOGRAPHIC AND NATURAL CONDITIONS .................................................. 21 1.3 ADMINISTRATIVE AND POLITICAL UNITS .......................................................... 23 1.4 DEMOGRAPHIC FEATURES .............................................................................. -
Mount Longonot National Park Include Hiking, Rock Climbing, Biking and Observing Birds and Wildlife
HOW TO GET THERE The park is accessible via tarmac road from Nairobi. From Naivasha town, take the lower (old) Nairobi - Naivasha road in the direction of Nairobi until you reach the Longonot railway level crossing. Turn right after the crossing and follow the track for 4km to the Park Gate and KWS offices. Vehicles may be left in a car park 1km after the gate. Open: Daily 6.00 a.m. - 6.00 p.m. including public holidays. Entry is allowed on foot, or in vehicles up to the parking bay, starting point for hiking. Also there is a game road circuit to the lava flow 2 km road (for) small vehicles. Current entry charges: Obtainable via KWS HQs:Tel: +254(20)6000800, 6002345 Fax: 6007024· Email: [email protected] • Website: www.kws.go.ke Smartcard required: At present the park does not operate on the smartcard system. Entry is by cash only (KShs or US $) Contact: The Warden, P.O.Box 234-20117 Naivasha - Kenya, Tel: (254-050) 50407/50290· Email: [email protected] KENYA WILDLIFE SERVICE PARKS AND RESERVES • ABERDARE NATIONAL PARK. AMBOSELI NATIONAL PARK. ARABUKO SOKOKE NATIONAL RESERVE • • CENTRAL &. SOUTHERN ISLAND NATIONAL PARK. CHYULU HILLS NATIONAL PARK • • HELLS GATE NATIONAL PARK. KAKAMEGA FOREST NATIONAL RESERVE. KISITE MpUNGUTI MARINE PARK • • KISUMU IMPALA SANCTUARY. KIUNGA NATIONAL MARINE RESERVE. KORA NATIONAL PARK • • LAKE NAKURU NATIONAL PARK. MALINDI MARINE NATIONAL PARK • • MARSABIT NATIONAL PARK &. RESERVE. MERU NATIONAL PARK. MOMBASA MARINE NATIONAL PARK • • MOMBASA MARINE RESERVE. MOUNT ELGON NATIONAL PARK. ~ ! ' • MT. KENYA NATIONAL PARK. MT. LONGONOT NATIONAL PARK. MWEA NATIONAL RESERVE. -
Kajiado County Renewable Energy Atlas
KAJIADO COUNTY RENEWABLE ENERGY ATLAS KAJIADO COUNTY RENEWABLE ENERGY ATLAS ALIN (2020) Kajiado County Renewable Energy Atlas Arid Lands Information Network (ALIN) 1st floor AAYMCA Building, State House Crescent off State House Avenue P.O. Box 10098 – 00100, Nairobi - KENYA This Atlas was prepared by ALIN in close collaboration with the Kajiado County Government, as represented by the Ministry of Water, Irrigation, Environment and Natural Resources with support from the Hivos Green and Inclusive Energy Programme. Copyright ©2020 Arid Lands Information Network (ALIN) Unless otherwise stated, material in this publication may be freely used, shared, copied, reproduced, printed and/or stored for educational or non-commercial purposes provided that appropriate acknowledgement is given of ALIN as the source and copyright holder. Reproduction of the publication for resale or other commercial purposes is however strictly prohibited, except with prior written permission from the copyright holder. About ALIN The Arid Lands Information Network (ALIN) is a non-governmental organization (NGO) registered in Kenya with over 20 years’ experience working on sustainable development issues by providing a grass-root link to policy matters in addition to empowerment activities. ALIN has been championing the use of ICTs to empower communities with usable information and knowledge to improve their livelihoods. www.alin.net Cover Design and layout by: Ngugi Wathuge Printed by: Regal Press Ltd ii Table of Content List of tables and figures ....................................................................................................................................v -
Geology and Hydrothermal Alteration of the North and West Exploration Wells in the Olkaria Geothermal Field, Kenya
187 Proceedings 9th Geothermal Workshop 1987 GEOLOGY AND HYDROTHERMAL ALTERATION OF THE NORTH AND WEST EXPLORATION WELLS IN THE OLKARIA GEOTHERMAL FIELD, KENYA T.M. LEACH* AND G.G. (* Chartered Mineral Services and GENZL) (** Kenya Power Company) ABSTRACT No large intrusive body or "basement" rock was encountered, although rarely micro-to porphyritic syenites, granites and diorites Petrographic, x-ray diffraction and fluid inclusion studies were were intersected in a few wells, and are interpreted to be sub- camed out cores and selected cuttings from ten exploration wells in volcanic to surface extrusives. Tracesyenite lithic fragments the north and western sectors of the Olkaria geothermal field. The were observed in some of the pyroclastics. wells penetrated a thick volcanic pile of alkali and minor lavas and pyroclastics, with rare intersections of high level PERMEABILITY intrusives. The main permeability in the formation occurs in widely spaced faults with little fracturing occurring within the fault blocks. Fracturing in the volcanic pile is not common, with only rare thin Lithological permeability is restricted to shallow levels, with veinlets observed in a minority of the cores. Fault intersections, hydrothermal mineral deposition sealing the primary porosity at based on core shearing, fracturing, brecciation and veining, were depth. The distribution of illitic and chloritic clays helps to determine noted in only a few samples. These cores had undergone intense the extent of the bicarbonate, and the alkaline chloride fluids alteration indicative of a high fluid to rock ratio. The depths encounteredin the reservoir. The distribution of kaolinite, smectite of these fault intersections are usually zones of major production and carbonates is used to delineatethe extent of cool recharge fluids. -
The Cenozoic Magmatism of East Africa: Part V – Magma Sources and Processes in the East African Rift
1 The Cenozoic Magmatism of East Africa: Part V – Magma Sources and Processes in the East African Rift Tyrone O. Rooney Dept. of Earth and Environmental Sciences, Michigan State University, East Lansing, MI 48823, USA Abstract The generation of magmas in the East African Rift System (EARS) is largely the result of either: (A) melting of easily fusible compositions located within the lithospheric mantle due to thermobaric perturbations of the lithosphere, or (B) melting of the convecting upper mantle due to decompression caused by thinning of the plate during extension. Melt generated from amphibole- or phlogopite-bearing metasomes within the lithospheric mantle yields alkaline, silica-undersaturated lavas, while more silica-saturated lavas are primarily a function of melting material within the convecting upper mantle. Sourcing of silica-undersaturated melts within the lithospheric mantle is consistent with the observed tendency for initial melts within any given region to exhibit trace element characteristics consistent with melting of lithospheric metasomes, likely reflecting the initial destabilization and thinning of the lithospheric mantle. With continued lithospheric thinning, the trend towards more silica-saturated compositions coincides with a shift towards compositions interpreted as melting of the convecting upper mantle. Contributions from these two sources may oscillate where extension is pulsed – melts of the convecting upper mantle are favored during periods of plate thinning; melting of either existing or recently formed metasomes may be favored during periods of relative extensional quiescence. The isotopic systematics of East African magmatism reveals significant complexity 1 Figure 1 Crust lithosp. Disseminated mantle phases amphibole,amphibole Fe-Ti Oxides & other phases pyroxenites asthensp. -
Resettlement Action Plan for the Loiyangalani - Suswa 400 Kv Transmission Line
Resettlement Action Plan for the Loiyangalani - Suswa 400 kV Transmission Line Addendum to Draft RAP Report January 2012 May 2013 Addendum to Draft RAP for the Loiyangalani – Suswa 400kV Transmission Line TABLE OF CONTENTS TABLE OF CONTENTS .................................................................................................... i LIST OF TABLES ............................................................................................................... v LIST OF FIGURES ......................................................................................................... vii ABBREVIATIONS AND ACRONYMS ....................................................................... ix GLOSSARY OF TERMS ................................................................................................. xi ACKNOWLEDGEMENTS ............................................................................................ xv A: PREAMBLE ............................................................................................................. xvi Background .................................................................................................................xvii Findings of the Draft RAP Report 2012 ...................................................................xvii Changes That Have Occurred Since Submission of Draft RAP Report ........... xviii Limitation/ Challenges to Progress .......................................................................... xx B: EXECUTIVE SUMMARY ...................................................................................