Keynote Speaker: Dave Cornell

Convener: R.J. Thomas

The African continent preserves a geological history dating back to the Archean, with rocks as old as 3.8 Ga. The Archean rocks are characterized by Archean granite-greenstone terrains which form cratonic nuclei’s. These early cratonic nuclei’s amalgamated in Neoarchean and Paleoproterozoic to form large cratons such as the Zimbabwe – Kaapvaal Craton, Congo Craton and West African Craton. The cratonisation of Archean crust was followed by sedimentation, volcanism and tectonics in the Paleoproterozoic era. These geological processes are associated with the formation of the Rodinia supercontinent at ca. 1 Ga. The 1.3 – 0.9 Ga orogenic event which lead to the formation of the supercontinent Rodinia is recorded by several mobile belts across Africa, including the Namaqua Natal belt in southern Africa and Kibaran Belt in central Africa. During the Neoproterozoic, the Rodinia supercontinent disintegrated (0.85 Ga) leading to the formation of ocean basins which became major depositional sites for Neoproterozoic sediments.  These oceans closed during the pan African orogeny at ca. 0.85 to 5.5 Ga leading to the formation of the Gondwana supercontinent and subsequently Pangea. The Rifting events split the Gondwana supercontinent in the late Jurrasic heralding the current configuration of the African continent. 

ST02-S01- Geochronology of the African continent and applications of new techniques- a window into the evolution of planet Earth.

Conveners: Martin Harris 

Geochronology, the study of determining the ages of rocks and geological events, has played a crucial role in unraveling the complex evolutionary history of the African continent. Through the application of various dating techniques, such as radiometric dating using isotopes like uranium-lead and potassium-argon, researchers have been able to establish accurate timelines for the formation of different geological features and events across Africa. These geochronological investigations have provided critical insights into the assembly and breakup of supercontinents, the formation of major tectonic boundaries, the development of ancient mountain ranges, and the timing of magmatic activity and volcanic eruptions. Furthermore, the advent of new techniques, such as high-precision dating methods and improved analytical capabilities, has enhanced our understanding of African geochronology. These advancements allow for more precise age determinations and the ability to date smaller mineral grains, providing a higher resolution view of Earth's evolution. Geochronology, as a window into the past, continues to illuminate the geological history of the African continent and contributes to our broader understanding of the dynamic processes that have shaped our planet.

ST02-S02-- Evolution of the Mobile belts of the African continent- a history of the Archean to the Phanerozoic. 

Conveners: Ben Mapani

The mobile belts of the African continent exhibit a rich and diverse history that spans from the Archean to the Phanerozoic eon. These mobile belts are the result of complex tectonic processes that have shaped the African continent over billions of years. During the Archean, several greenstone belts formed, representing ancient volcanic and sedimentary sequences. These belts provide insights into early crustal evolution and the formation of some of the world's oldest rocks. In the Proterozoic, collisional events led to the assembly of supercontinents, such as Rodinia and Gondwana, resulting in the formation of mobile belts with folded and faulted rocks. The Pan-African orogeny, which occurred in the Neoproterozoic, marked a significant episode of continental collision and mountain building in Africa. This event resulted in the formation of numerous mobile belts, including the Mauritanide, West African, and Mozambique belts. These belts are characterized by a wide range of tectonic features, including thrust faults, shear zones, and metamorphic rocks. In the Phanerozoic, the opening and closure of ocean basins, such as the Atlantic and Indian Ocean, further influenced the evolution of the mobile belts. The African mobile belts bear witness to the dynamic and complex geological history of the continent, providing valuable insights into Earth's tectonic processes and the formation of its diverse geological features.

S02ST02_S03- Intraplate magmatism-magmatic processes in the formation of continents.

Convener: Mbili Tshiningayamwe

Intraplate magmatism plays a crucial role in the formation and evolution of continents. It occurs in regions located within the interior of tectonic plates, far from plate boundaries, where magma rises to the surface and generates volcanic activity. The processes involved in intraplate magmatism are complex and varied. One common mechanism is mantle plumes, which are hot upwellings of material from deep within the Earth's mantle. As these plumes ascend, they can partially melt the overlying lithosphere, leading to the formation of large igneous provinces and voluminous basaltic lava flows. In other cases, the lithosphere can undergo extension and thinning, creating space for magma to ascend and form volcanic centers known as rift-related intraplate magmatism. These magmatic processes contribute to the growth and stabilization of continental crust by adding new material through volcanic activity and the emplacement of intrusive rocks. Intraplate magmatism also plays a role in the mineralization of valuable resources, such as copper and gold deposits, enriching the continental crust. Understanding the dynamics and processes associated with intraplate magmatism is essential for comprehending the complex interplay between magmatic activity and the formation of continents.