The Formation and Evolution of Africa from the Archaean to Present: Introduction
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The Western Branch of the East African Rift: a Review of Tectonics, Volcanology and Geothermal Activity
Presented at SDG Short Course IV on Exploration and Development of Geothermal Resources, organized by UNU-GTP and KenGen, at Lake Bogoria and Lake Naivasha, Kenya, Nov. 13 – Dec. 3, 2019. THE WESTERN BRANCH OF THE EAST AFRICAN RIFT: A REVIEW OF TECTONICS, VOLCANOLOGY AND GEOTHERMAL ACTIVITY Björn S. Hardarson Iceland GeoSurvey (ÍSOR) Grensásvegur 9, 108 Reykjavik ICELAND [email protected] ABSTRACT The East African Rift System (EARS) is a classic example of continental rifting and provides an excellent framework to study extensional magmatism and the evolution of several central volcanic systems that have formed along the rift from the Tertiary to Recent. Many of the volcanic structures have developed substantial high-temperature geothermal systems where the heat source is magmatic and related to central volcanoes. Detailed studies indicate that the geothermal potential in Eastern Africa is in the excess of 15,000 MWe. However, despite the high geothermal potential of EARS only Kenya has installed significant capacity of about 570 MW. Magmatism along the EARS is generally believed to be associated with mantle plume activities but the number and nature of mantle plumes is still, however, controversial. EARS is divided into two main branches, the Eastern- and Western rifts, and it is well documented that significantly greater volcanism is observed in the older Eastern rift (i.e. Ethiopia and Kenya) compared to that in the younger Western rift, where eruptive activity is, in general, restricted to four spatially distinct provinces along the rift axis. These are the Toro-Ankole in western Uganda, the Virunga and Kivu provinces along the border of the DRC with Uganda, Rwanda and Burundi, and the Rungwe volcanic field in SW Tanzania. -
Durham Research Online
Durham Research Online Deposited in DRO: 13 April 2015 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: Kaislaniemi, L. and van Hunen, J. (2014) 'Dynamics of lithospheric thinning and mantle melting by edge-driven convection : application to Moroccan Atlas mountains.', Geochemistry, geophysics, geosystems., 15 (8). pp. 3175-3189. Further information on publisher's website: http://dx.doi.org/10.1002/2014GC005414 Publisher's copyright statement: c 2014. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modications or adaptations are made. Additional information: Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full DRO policy for further details. Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk PUBLICATIONS Geochemistry, -
Continental Complexities: a Multidisciplinary Introduction to Africa
Continental Complexities A Multidisciplinary Introduction to Africa By Dr. Ibigbolade Simon Aderibigbe and Dr. Akinloye Ojo Included in this preview: • Table of Contents • Chapter 1 & 2 For additional information on adopting this book for your class, please contact us at 800.200.3908 x501 or via e-mail at [email protected] Dpoujofoubm!Dpnqmfyjujft A MULTIDISCIPLINARY INTRODUCTION TO AFRICA Revised Edition Edited by Ibigbolade Aderibigbe and Akinloye Ojo University of Georgia Bassim Hamadeh, CEO and Publisher Christopher Foster, General Vice President Michael Simpson, Vice President of Acquisitions Jessica Knott, Managing Editor Kevin Fahey, Cognella Marketing Manager Jess Busch, Senior Graphic Designer Zina Craft , Acquisitions Editor Jamie Giganti, Project Editor Brian Fahey, Licensing Associate Copyright © 2013 by Cognella, Inc. All rights reserved. No part of this publication may be reprinted, reproduced, transmitted, or utilized in any form or by any electronic, mechanical, or other means, now known or hereaft er invented, including photocopying, microfi lming, and recording, or in any information retrieval system without the written permission of Cognella, Inc. First published in the United States of America in 2013 by Cognella, Inc. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identifi cation and explanation without intent to infringe. Printed in the United States of America ISBN: 978-1-62131-133-1 (pbk) Contents The Study of Africa: An Introduction 1 Ibigbolade Aderibigbe -
Africa-Arabia-Eurasia Plate Interactions and Implications for the Dynamics of Mediterranean Subduction and Red Sea Rifting
This page added by the GeoPRISMS office. Africa-Arabia-Eurasia plate interactions and implications for the dynamics of Mediterranean subduction and Red Sea rifting Authors: R. Reilinger, B. Hager, L. Royden, C. Burchfiel, R. Van der Hilst Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA, [email protected], Tel: (617)253 -7860 This page added by the GeoPRISMS office. Our proposed GeoPRISMS Initiative is based on the premise that understanding the mechanics of plate motions (i.e., the force balance on the plates) is necessary to develop realistic models for plate interactions, including processes at subduction and extensional (rifting) plate boundaries. Important advances are being made with new geologic and geophysical techniques and observations that are providing fundamental insights into the dynamics of these plate tectonic processes. Our proposed research addresses directly the following questions identified in the GeoPRISMS SCD Draft Science Plan: 4.2 (How does deformation across the subduction plate boundary evolve in space and time, through the seismic cycle and beyond?), 4.6 (What are the physical and chemical conditions that control subduction zone initiation and the development of mature arc systems?), and 4.7 (What are the critical feedbacks between surface processes and subduction zone mechanics and dynamics?). It has long been recognized that the Greater Mediterranean region provides a natural laboratory to study a wide range of geodynamic processes (Figure 1) including ocean subduction and continent- continent collision (Hellenic arc, Arabia-Eurasia collision), lithospheric delamination (E Turkey High Plateau, Alboran Sea/High Atlas), back-arc extension (Mediterranean basins, including Alboran, Central Mediterranean, Aegean), “escape” tectonics and associated continental transform faulting (Anatolia, North and East Anatolian faults), and active continental and ocean rifting (East African and northern Red Sea rifting, central Red Sea and Gulf of Aden young ocean rifting). -
Geological Evolution of the Red Sea: Historical Background, Review and Synthesis
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/277310102 Geological Evolution of the Red Sea: Historical Background, Review and Synthesis Chapter · January 2015 DOI: 10.1007/978-3-662-45201-1_3 CITATIONS READS 6 911 1 author: William Bosworth Apache Egypt Companies 70 PUBLICATIONS 2,954 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Near and Middle East and Eastern Africa: Tectonics, geodynamics, satellite gravimetry, magnetic (airborne and satellite), paleomagnetic reconstructions, thermics, seismics, seismology, 3D gravity- magnetic field modeling, GPS, different transformations and filtering, advanced integrated examination. View project Neotectonics of the Red Sea rift system View project All content following this page was uploaded by William Bosworth on 28 May 2015. The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. Geological Evolution of the Red Sea: Historical Background, Review, and Synthesis William Bosworth Abstract The Red Sea is part of an extensive rift system that includes from south to north the oceanic Sheba Ridge, the Gulf of Aden, the Afar region, the Red Sea, the Gulf of Aqaba, the Gulf of Suez, and the Cairo basalt province. Historical interest in this area has stemmed from many causes with diverse objectives, but it is best known as a potential model for how continental lithosphere first ruptures and then evolves to oceanic spreading, a key segment of the Wilson cycle and plate tectonics. -
Pan-African Orogeny 1
Encyclopedia 0f Geology (2004), vol. 1, Elsevier, Amsterdam AFRICA/Pan-African Orogeny 1 Contents Pan-African Orogeny North African Phanerozoic Rift Valley Within the Pan-African domains, two broad types of Pan-African Orogeny orogenic or mobile belts can be distinguished. One type consists predominantly of Neoproterozoic supracrustal and magmatic assemblages, many of juvenile (mantle- A Kröner, Universität Mainz, Mainz, Germany R J Stern, University of Texas-Dallas, Richardson derived) origin, with structural and metamorphic his- TX, USA tories that are similar to those in Phanerozoic collision and accretion belts. These belts expose upper to middle O 2005, Elsevier Ltd. All Rights Reserved. crustal levels and contain diagnostic features such as ophiolites, subduction- or collision-related granitoids, lntroduction island-arc or passive continental margin assemblages as well as exotic terranes that permit reconstruction of The term 'Pan-African' was coined by WQ Kennedy in their evolution in Phanerozoic-style plate tectonic scen- 1964 on the basis of an assessment of available Rb-Sr arios. Such belts include the Arabian-Nubian shield of and K-Ar ages in Africa. The Pan-African was inter- Arabia and north-east Africa (Figure 2), the Damara- preted as a tectono-thermal event, some 500 Ma ago, Kaoko-Gariep Belt and Lufilian Arc of south-central during which a number of mobile belts formed, sur- and south-western Africa, the West Congo Belt of rounding older cratons. The concept was then extended Angola and Congo Republic, the Trans-Sahara Belt of to the Gondwana continents (Figure 1) although West Africa, and the Rokelide and Mauretanian belts regional names were proposed such as Brasiliano along the western Part of the West African Craton for South America, Adelaidean for Australia, and (Figure 1). -
Insights on the Crustal Evolution of the West African (Raton from Hf Isotopes in Detrital Zircons from the Anti-Atlas Belt
Insights on the crustal evolution of the West African (raton from Hf isotopes in detrital zircons from the Anti-Atlas belt a b c d b ]acobo Abati ,., Abdel Mohsine Aghzer , 1 , Axel Gerdes , ,2, Nasser Ennih • Departamento de Petrologfa y Geoquimica and Instituto de Geologia Econ6mica, Universidad Comp!utense/Consejo Superior de Investigaciones Cientificas. 28040 Madrid, Spain b Departament Ge% gie. Faculte des Sciences, Universite Chouaib Doukkali, EIJadida. Morocco c InstitutftirGeowissenschaften. Minera/ogie, Goethe-UniversityFrankfurt (GUF),Altenhoferallee 1. D-60438 Frankfurt amMain, Gennany d Department of Earth Sciences, SteIIenbosch University.Private BagXl. Matieland 7602, South Africa ABSTRACT The Lu-Hf isotopic composition of detrital zircons has been used to investigate the crustal evolution of the northern part of the West African (raton (WAC). The zircons were separated from six samples of siliciclastic sedimentary rocks from the main Neoproterozic stratigraphic units of the Anti-Atlas belt, from the SiIWa and Zenaga inliers. The data suggest that the north part of the WAC formed during three cycles of juvenile crust formation with variable amount of reworking of older crust. The younger group of zircons, with a main population clustering around 610 Ma, has a predominant juvenile character and Keyworili: evidences of moderate mixing with Paleoproterozoic and Neoarchean crust, which supports that most Anti-Atlas belt igneous and metamorphic rocks where zircons originally crystallized were formed in an ensialic mag Morocco Hfisotopes matic arc environment. The group of zircons in the age range 1.79-2.3 Ca corresponds to the major crust Detrital zircon forming event in the WAC: the Eburnian orogeny. -
Mesozoic and Cenozoic Thermal History of the Western Reguibat Shield West African Craton)
This is a repository copy of Mesozoic and Cenozoic thermal history of the Western Reguibat Shield West African Craton). White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/124296/ Version: Accepted Version Article: Gouiza, M orcid.org/0000-0001-5438-2698, Bertotti, G and Andriessen, PAM (2018) Mesozoic and Cenozoic thermal history of the Western Reguibat Shield West African Craton). Terra Nova, 30 (2). pp. 135-145. ISSN 0954-4879 https://doi.org/10.1111/ter.12318 © 2017 John Wiley & Sons Ltd. This is the peer reviewed version of the following article: Gouiza M, Bertotti G, Andriessen PAM. Mesozoic and Cenozoic thermal history of the Western Reguibat Shield (West African Craton). Terra Nova. 2018;30:135–145. https://doi.org/10.1111/ter.12318, which has been published in final form at https://doi.org/10.1111/ter.12318. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Uploaded in accordance with the publisher's self-archiving policy. Reuse Items deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. This is indicated by the licence information on the White Rose Research Online record for the item. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. -
Black, R. & J.-P. Liegeois, Cratons, Mobile Belts, Alkaline Rocks And
Journal of the Geological Society, London, Vol. 150, 1993, pp. 89-98, 8 figs. Printed in Northern Ireland Cratons, mobile belts, alkaline rocks and continental lithospheric mantle: the Pan-African testimony R. BLACK l& J.-P. LIEGEOIS 2 1CNRS, URA 736, Laboratoire de Minkralogie, Muskum National d'Histoire Naturelle, 61 rue Buffon, 75005 Paris, France 2Dkpartement de Gkologie (Section de Gkochronologie) Muske Royal de l'Afrique Centrale, 3080 Tervuren, Belgique Abstract: Several late-collision and intraplate features are not entirely integrated in the classical plate tectonic model. The Pan-African orogeny (730-550 Ma) in Saharan Africa provides some insight into the contrasting behaviour of cratons and mobile belts. Simple geophysical considerations and geological observations indicate that rigidity and persistence of cratons are linked to the presence of a thick mechan- ical boundary layer, the upper brittle part of the continental lithospheric mantle, well attached to an ancient weakly radioactive crust. The surrounding Pan-African mobile belts, characterized by a much thinner mechanical boundary layer and more radioactive crust, were the locus of A-type granitoids, volcanism, tectonic reactivation and basin development during the Phanerozoic. During oceanic closures leading to the assembly of Gondwana, lithosphere behaviour was controlled by its mechanical boundary layer, the crust being much less rigid. We suggest that the 5000 km wide Pan-African domain of Saharan Africa, a collage of juvenile and old reactivated basement terranes, -
Sa˜O Luıs Craton and Gurupi Belt (Brazil)
Sa˜o Luı´s Craton and Gurupi Belt (Brazil): possible links with the West African Craton and surrounding Pan-African belts E. L. KLEIN1,2 & C. A. V. MOURA3 1CPRM (Companhia de Pesquisa de Recursos Minerais)/Geological Survey of Brazil, Av. Dr. Freitas, 3645, Bele´m-PA, CEP 66095-110, Brazil (e-mail: [email protected]) 2Researcher at CNPq (Conselho Nacional de Desenvolvimento Cientı´fico e Tecnolo´gico) 3Laborato´rio de Geologia Isoto´pica/Para´-Iso, Universidade Federal do Para´, Centro de Geocieˆncias, CP 1611, Bele´m-PA, Brazil, CEP 66075-900 Abstract: The Sa˜o Luı´s Craton and the Palaeoproterozoic basement rocks of the Neoproterozoic Gurupi Belt in northern Brazil are part of an orogen having an early accretionary phase at 2240– 2150 Ma and a late collisional phase at 2080 + 20 Ma. Geological, geochronological and isotopic evidence, along with palaeogeographic reconstructions, strongly suggest that these Brazilian terrains were contiguous with the West African Craton in Palaeoproterozoic times, and that this landmass apparently survived subsequent continental break-up until its incorporation in Rodinia. The Gurupi Belt is an orogen developed in the southern margin of the West African–Sa˜o Luı´s Craton at c. 750–550 Ma, after the break up of Rodinia. Factors such as present-day and possible past geographical positions, the timing of a few well-characterized events, the structural polarity and internal structure of the belt, in addition to other indirect evidence, all favour correlation between the Gurupi Belt and other Brasiliano/Pan-African belts, especially the Me´dio Coreau´ domain of the Borborema Province and the Trans-Saharan Belt of Africa, despite the lack of proven physical links between them. -
The Saharides and Continental Growth During the Final Assembly of Gondwana-Land
Reconstructing orogens without biostratigraphy: The Saharides and continental growth during the final assembly of Gondwana-Land A. M. Celâl S¸ engöra,b,1, Nalan Lomc, Cengiz Zabcıb, Gürsel Sunalb, and Tayfun Önerd aIstanbul_ Teknik Üniversitesi (ITÜ)_ Avrasya Yerbilimleri Enstitüsü, Ayazaga˘ 34469 Istanbul,_ Turkey; bITÜ_ Maden Fakültesi, Jeoloji Bölümü, Ayazaga˘ 34469 Istanbul,_ Turkey; cDepartement Aardwetenschappen, Universiteit Utrecht, 3584 CB Utrecht, The Netherlands; and dSoyak Göztepe Sitesi, Üsküdar 34700 Istanbul,_ Turkey Contributed by A. M. Celâl S¸ engör, October 3, 2020 (sent for review July 17, 2020; reviewed by Jonas Kley and Leigh H. Royden) A hitherto unknown Neoproterozoic orogenic system, the Sahar- identical to those now operating (the snowball earth and the ab- ides, is described in North Africa. It formed during the 900–500-Ma sence of land flora were the main deviating factors), yet the interval. The Saharides involved large subduction accretion com- dominantly biostratigraphy-based methods used to untangle oro- plexes occupying almost the entire Arabian Shield and much of genic evolution during the Phanerozoic are not applicable Egypt and parts of the small Precambrian inliers in the Sahara in- to them. cluding the Ahaggar mountains. These complexes consist of, at least by half, juvenile material forming some 5 million km2 new Method of Reconstructing Complex Orogenic Evolution in continental crust. Contrary to conventional wisdom in the areas the Neoproterozoic without Biostratigraphy: Example of the they occupy, -
Mineralization and Sustainable Development in the West African Craton: from field Observations to Modelling
Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 Mineralization and sustainable development in the West African Craton: from field observations to modelling Tahar Aïfa Université de Rennes, CNRS, Géosciences Rennes–UMR 6118, Bât. 15, Campus de Beaulieu, 35042 Rennes, France 0000-0002-1573-7668 [email protected] Abstract: This Special Publication combines results obtained by interdisciplinary groups from numerous aca- demic institutions working on Paleoproterozoic formations to decipher the origins of the main mineralization resources in the West African Craton (WAC) and their impacts on African economic development. Structural, geophysical, sedimentological, stratigraphical, geochemical, petrophysical and mineralogical analyses have been used to highlight the complexities involved in mineralization emplacement and its origin and evolution within the WAC. Fourteen articles, mainly of basic research carried out in the WAC and surrounding areas, contribute to new knowledge in mineral research with updated references. They show that the geodynamic evo- lution of the WAC is complex from one area to another: it involves subduction, collision and obduction during several deformation phases ranging from Birimian (2.3–2.0 Ga) to Pan-African (650–450 Ma) events. Miner- alization is mainly controlled by tectonics within shear zones, orogenic belts, basins and faulting systems occur- ring in the various corridors. Mineralized fluid circulation is stressed and injected into appropriate formations and precipitate several types of well-documented ore deposits: porphyry, metal-bearing, volcanogenic massive sulfide, sedimentary exhalative and lateritic. Various modelling techniques, when integrated, help in under- standing the mechanisms of mineralization emplacement, some of which are still a matter of debate.