•••, A v~*«^» í f >-v ,— / PER-58 THE URANIUM GEOLOGY AND TECTONIC CORRELATION BETWEEN THE AFRICAN AND LATIN AMERICAN CONTINENTS by P.D. Toens J.P. le Roux C.J.H. Hartnady W.J. van Biljon /| ATOMIC ENERGY BOARD _i, j Pelinclaha T> J! PRETORIA x | Republic of South Africa October 1980 8 .ii. ::iii!!:imi:::: gjpji, lip£.l.^....diyiii^..,».M!i» *ltji|ill I «•••*«••• •••«•If*III(**««*}«atja•*••••**•••*•***<*••••• «•(•I<>«lil«ll»»"<'->1 I.. !!::::i::!ii:J:i:: PER-58 THE URANIUM GEOLOGY AND TECTONIC CORRELATION BETWEEN THE AFRICAN AND LATIN AMERICAN CONTINENTS by P.D. Toens* J.P. le Roux* C.J.H. Hartnady** W.J. van Biljon*** *Geo1ogy Division POSTAL ADDRESS: Private Bag X256 PRETORIA 0001 **University of Cape Town ***Rand Afrikaans University PELINDABA October 1980 [OnÁQÍnaíly pfiuzntíd cu> an intoxÁm Kzpoht by thz South A^fvican Walking Gnoixp to thz IAEA Consultants' Mz&ting, Vienna, JLU.IJ 1980) ISBN 0 86960 720 0 PER-58-1 CONTINENTS, LIKE PEOPLE, CAW MO LONGER BE STUV1EV EFFECTIVELY IN/ ISOLATION. PER-58-2 MIEVATTIH8 CONTENTS Page ABSTRACT 1. GENERAL STATEMENT 7 2. INTRODUCTION 8 3. CORRELATION OF METALLOGENIC PROVINCES 11 4. PRE-DRIFT RECONSTRUCTION OF WEST GONDWANALAND 14 4.1 Accuracy and Precision of Reconstruction 14 4.2 Basic Review of Previous Reconstructions 15 4.3 Proposed New Reconstruction 16 5. RELATIONSHIP BETWEEN MAJOR URANIUM METALLOGENIC 18 PROVINCES AND GEOTECTONIC PROVINCES 6. PERMO-TRIASSIC GONDWANA BASINS 21 6.1 Tectonic Setting 21 6.2 Description of Uranium Deposits in Gondwana 30 (Karoo) Basins 6.2.1 Main Karoo Basin 30 6.2.2 Waterberg Basin 32 6.2.3 Botswana Basin 32 6.2.4 Limpopo Basin 33 6.2.5 Mozambique Basin 33 6.2.6 Etjo Basin 33 6.2.7 Ovambo Basin 33 6.2.8 Mid-Zambezi Basin 34 6.2.9 Lower-Zambezi Basin 35 6.2.10 Barotse Basin 35 6.2.11 Angola Basin 36 6.2.12 Luano-Luangwa Basin 36 6.2.13 East African Basin 36 6.2.14 Rukwa Basin 36 6.2.15 Congo Basin 37 6.2.16 Gabon Basin 37 6.2.17 Parana Basin (Southern Brazil) 37 6.2.18 Callingasta-Uspallata Basin (Argentina) 37 7. URANIUM DEPOSITS RELATED TO CARBONATITE AND 38 ALKALINE INTRUSIONS 7.1 Tectonic Setting 38 7.2 Description of Uranium Deposits 42 ) PER-58-3 Page 7.2.1 Phalaborwa, Transvaal 42 7.2.2 Pilanesberg, Transvaal 43 7.2.3 Bonga, Angola 43 7.2.4 Pocos de Caldas, Brazil 44 PAN-AFRICAN-BRASILIANO PROVINCES 44 8.1 Tectonic Setting 44 8.2 Correlations 50 8.2.1 Zaire deposits 50 8.2.2 Damara Belt (Rossing region) 53 uranium deposits PRE-PAN-AFRICAN URANIUM PROVINCES 55 9.1 Mamaqua-Natal Mobile Belt 55 9.1.1 Uranium potential 58 9.2 Eburnian Mobile Belt 59 9.3 Ancient Cratons 59 9.3.1 The Witwatersrand Triad 61 9.3.2 Other occurrences in South Africa 63 9.3.3 Brazilian quartz-pebble conglomerates 64 9.3.4 Remarks 65 CONCLUSIONS 66 REFERENCES 66 LIST OF FIGURES 1 Metallogenic provinces of Western Gondwanaland 13 (after Leube, 1976) 2 Gondwana Karoo Basins in Southern Africa and 22 South America 3 Distribution of alkaline complexes and k'.mberlite 39 in Southern Africa and South America 4 Relationship between the Ribeira Belt in South 48 America, and the Damara and Gariep Belts of Southern Africa PER-58-4 Page FIG. 5 Cratons and mobile belts of Southern Africa 56 FIG. 6 The Namaqua-Natal Mobile Belt and adjacent 57 tectonic areas (after Blignault, 1974; Joubert 1974; Jacob ei aJL 1980) FIG. 7 Precambrian cover rocks of South Africa 60 LIST OF TABLES TABLE I Mineralised areas in West Africa and Eastern 14 South America (mostly after Leube, 1S76) TABLE II Finite rotations describing the relative 16 motions of Africa and South America - Summary from 1968 to 1980 TABLE III Correlation of the Karoo sequences in 23 African Gondwana Basins TABLE IV List of Alkaline Complexes in Africa south 40 of the equator as given in Fig. 3 PER-58-5 SAMEVATTING In opvolging van ft vergadering van die Internasionale Atoomenergie= agentskap se Adviesgroep vir Uraangeologie in Latyns-Amerika wat in Desember 1978 in Lima, Peru, gehou is, is daar besluit dat Yi projek vir die korrelering van uraangeologie aan beide kante van die Atlantiese Oseaan noodsaaklik geword het. Die verteenwoordigers van die betrokke lande is versoek om in Julie 1980 in Wenen te vergader en tussentydse verslae oor die vordering wat met die projek gemaak is, in te dien. Hierdie referaat verteenwoordig tt tussentydse verslag deur die Suid-Afrikaanse Werkgroep. Aspekte wat behandel word, is die passing van die twee vastelande, die aard en ver= spreiding van die Gondwana- en vroeër opeenvolgings, asook die aard en verspreiding van uraa.onoudende alkalikomplekse en graniete. ABSTRACT Subsequent to a meeting of the International Atomic Energy Agency's Advisory Group on Uranium Geology in Latin America held in Lima, Peru in December 1978, it was decideo that a project involving the corre­ lation of uranium geology on either side of the Atlantic was called for. The representatives of the countries concerned were asked to meet in Vienna in July 1980 and present interim reports on progress made in their respective countries on this project. This paper represents an interim report by the South African Working Group. The aspects dealt with cover the matching of the two continents, the nature and distri= bution of the Gondwana and earlier sequences, as well as the nature and distribution of uraniferous alkaline complexes and granites. PER-58-6 ACKNOWLEDGEMENTS Acknowledgement is made to the President and Deputy President of the South African Atomic Energy Board, Dr J.W.L. de Villiers and Dr J.P. Hugo respectively, for making participation in this project possible. Their interest and encouragement are much appreciated. The assistance of Dr B.B. Hambleton-Jones, Messrs H.J. Brynard, C.J.B. Smit and Mrs T.M.T. Kloppers is gratefully acknowledged. Thanks are also due to the University of Cape Town and the Rand Afrikaans University for making available the services of Dr Hartnady and Professor Van Biljon respectively. PER-58-7 1. GENERAL STATEMENT At a meeting of the International Atomic Energy Agency's Advisory Group on Uranium Geology *n Latin America held in Lima, Peru in December 1978 and at which South Africa was ^presented by P.D. Toens, it was agreed that there is excellent scope for cooperation between Latin American and African countries sharing a common geology and similar metallogenic trends. It was therefore felt that a concerted effort should be made to bring together geoscientists involved in uranium exploration and assessment, in order to clearly define metallogenic mooels for uranium ore deposits likely to have meaningful patterns within pre-drift Western Gondwana. A formula for cooperation between interested countries was devised under the auspices of the International Atomic Energy Agency. The proposed final objective of the South American/African correlation should be: (a) To draw a complete metallogenic map (or a series of two or four such maps) of pre-drift Western Gondwanaland at a scale of 1:10 000 000 showing all the known significant uranium deposits and occurrences. Only relevant geological and tec= tonic features should be shown on the map. (b) To make a brief summary of the known uraniferous deposits of Western Gondwanaland indicating age, ore-forming processes, mineralogy and relevant bibliography. (c) To make specific recommendations on furthering uranium explora= tion along preferred patterns on the two sides of the Atlantic. Preferred areas and exploration guides should be clearly defined. Each participating country was asked to form a Working Group to commence studies or projects, the results of which could eventually be incorpo= rated into a document which would deal with the whole of Western Gondwanaland. The South African Working Group is composed as follows: PER-58-8 P.D. Toens : Convenor (Atomic Energy Board) J.P. le Roux (Atomic Energy Board) W.J. van Biljon (Rand Afrikaans University) C.J.H. Hartnady (University of Cape Town) The first consultants' meeting is due to take place in Vienna during the period 21 - 25 July 1980, to which the following countries have been invited: Argentina (Belluco or Rodrigo) Brazil (Cordani and Angeiras or Forman) France (Bigotte) Germany (Gatzweiler and Ballhorn) Italy (Papadia) Nigeria (Koutoubi) South Africa (Toens and Van Biljon) Venezuela (Pasquali) Each participating delegation was requested to present a progress report at this meeting on studies carried out to date which may represent suitable material for incorporation in the volume dealing with the uranium geology of Western Gondwanaland. This paper, in the form of an interim report by the South African Working Group, represents progress made to date by the group and is tabled in the hope that it will lead to fruitful discussion. 2. INTRODUCTION By the very nature of the project in hand, we are far more concerned with the extrapolation of mineral provinces across the Atlantic than with the actual mechanics of plate movement. Nevertheless, it is as well to review some of the pertinent studies by previous researchers in this field with special reference to the southern half of Africa and eastern South America. In 1927 A.L. du Toit published his "Geological Comparison of South America with South Africa". His findings had a considerable influence on geolo= gical thinking in South America and Africa and was translated into Portuguese in 1952. PER-58-9 The similarities in the stratigraphy of Gondwanaland established by his study are so striking that it remains one of the cornerstones on which the hypothesis of Continental Drift, which eventually led to the establishment of the concept of Plate Tectonics, is based.