Geological Mapping of Angola An example of knowledge share between GeoSurveys of Europe and Africa

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1 EGS - ASGMI DIRECTOR S JOINT WORKSHOP October 2015 Geological Mapping of Angola An example of knowledge share between GeoSurveys of Europe and Africa Teresa Ponce de Leão LNEG

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3 LNEG National Laboratory for Energy and Geology LEN Laboratory of Energy Member of European Energy Research Alliance EERA LGM Laboratory of Geology and Mining Member of the European Geological Surveys EGS GEOLOGICAL MUSEUM >2.000 Profissionals equivalent

4 PLANAGEO ANGOLA NATIONAL PLAN FOR GEOLOGY Opportunity for the IBERIAN GeoSurveys REPÚBLICA DE ANGOLA COMISSÃO DE REESTRUTURAÇÃO E CAPACITAÇÃO DO INSTITUTO GEOLÓGICO DE ANGOLA International tender launched in 2011 Targeted by very specific objectives for the geological mapping of the whole country Driven by realistic goals for the economy of geological resources Aero-geophysics surveying Geological mapping at 1/250k scale Geochemical mapping at 1/250k scale Geological mapping of areas of specific economic interest 1/100k scale Non-metallic resources mapping of restrict areas Partnership between LNEG and IGME and IMPULSO (private enterprise) 1/3 of the territory was attributed to the Iberian Consortium (SW and part of S regions)

5 BACKGROUND Former Experience of LNEG in ANGOLA 20 years of cooperation with IGEO: Exceptional knowledge of Geology of Angola Reworking of Geology of Angola for application of new models of validity at continental scale Mapping of key areas with specific geological settings Impulo-Chongoroi (2001); Bibala (2006); Chibia (2013) IGEO staff capacity building Geology of SW Angola (monography 2013)

6 PLANAGEO started Jan 2014 with a good knowledge of the Geology of Angola 4 GEOTECTONIC UNITS: - Congo Craton (5 blocks) - Block NE (Lunda) - Block NW (Congo) - Block Center-W - Block Center-E (Cassinga) - Block SW (Namibe) - Mobile Belts - Eburnean Cycle - Pan-African/Brasilian cycle - Sedimentary Continental Basins - Karoo - Kalahari - Perioceanic Basins - Congo - Kuanza - Namibe

7 Main guidelines for geological surveying of ancient terrains a) CONGO CRATON The 5 cratonic Blocs were amalgamated during the Eburnean cycle (2 Gy) to form the CONGO CRATON. b) MOBILE OROGENIC BELTS The history behind the Eburnenan cycle has to be sought - isotope studies, tectonics and petrology of the ancient tectono-thermic complexes: - Charnoquits of Dybaia (Lunda) 2,82 Gy - Quilombo granites and granitoids 2,6 Gy - Moxico and Lunda-S gneisses and migmatites 2,8 Gy - Idem of Cariango, Andulo and SW 2,5 GY Later, during the Pan-African/Brasilian cycle (650 My) other orogenic belts were accreted: - Ocidental Congo - Kahoko - Katanga (Lufiliano) All those events occurred before the opening of the South Atlantic

8 Eburnean geodynamic model proposed for SW of Angola Frontal collision between São Francisco and Congo blocks key for interpretation of the variety of Plutonic Rocks Magmatic Arch Recrystalized porphiritic Quartz-Feldspar Acidic calco-alkaline plutonism Intermediate-mafic calcoalkaline plutonism Upper crustal rocks Eburnean remobiolization of crustal materials

9 PETROLOGIC RESEARCH Ultramafic rocks (dunites and gabro cumulates) Mafic and intermediate acidic rocks (of magmatic arch): - Gabros, Diorites - Mingling of acidic and intermediate magmas

10 Geology of the SW Angola re-interpreted THE EBURNEAN MODEL The cooperation between LNEG and IGEO in previous years allowed the definition and characterization of the Eburnean Cycle: 1,8 1,9 Gy (isotope data) Dunites and other ultrabasic rocks (petrology) Mingling of different calcoalkaline magmas Interesting potential for generating Cu, Pb, Zn, Au resources In the past those formations where referred to as belonging to the Gabro-Anortositic Complex, 500 My younger.

11 SEDIMENTARY CONTINENTAL BASINS The Tectonic context Collision between Patagonia and Gondwana at the end of Paleozoic formed continental basins and semi-grabens: - Karoo permo-jurassic Later W-E distensive tectonics (coeval of the Atlantic opening) was favorable to the reactivation of former structures, allowing the installation of kimberlites and deposition of Kwango Group. Distribution of Karoo Basins

12 THE PERIOCEANIC BASINS These OCEANIC BASINS were formed during the opening of the South Atlantic: - Congo - Kwanza - Namibe In upper Terciary (Neogenic) continental sedimentary processes developed to form the Kalahari Group Kalahari

13 PLANAGEO OPERATIONAL PLAN for Geological Mapping and field work Starting point ancient surveys and drawings from the colonial period - Remote sensing techniques: - Satellite images - Treated Satellite images (spectra)

14 PLANAGEO OPERATIONAL PLAN for Geological Mapping and field work Starting point ancient surveys and drawings from the colonial period - Remote sensing techniques: - Satellite images - Treated Satellite images (spectra) - Aerogeophysisc - Radiometry - Magnetics Preliminary maps with geological column harmonized for all Angola territory Establishment of tracks for field work validation

15 PUNGO ANDONGO REGION Pan African W-Congo Mobile Belt Kingdom of the legendary Queen GINGA A native warrior woman ( ) that fought against slavery Her royal title of NGOLA were used by Portuguese people to refer that part of the country

16 TAZUA-CUANGO WATER FALLS Pan African W-Congo Mobile Belt

17 IONA moutains SW Kahoco Pan-African Mobile Belt

18 KUNENE RIVER and Kahoco Pan-African Mobile Belt outcrops

19 HEREROS Himba Tribe (Angola Namibia border) Matriarchal society where Women are the Leaders

20 Himba women in the Namibe Desert

21 Obrigada pela vossa atenção