when did gondwana split into africa and south america
Gondwana The opening of the South Atlantic Ocean divided West Gondwana (South America and Africa), but there considerable debate over the exact timing of this break-up. Rifting propagated from south to north along Triassic–Early Jurassic lineaments, but intra-continental rifts also began to develop within both continents in Jurassic–Cretaceous sedimentary basins; subdividing each continent into three sub-plates. Rifting began c. 190 Ma at Falkland latitudes, forcing Patagonia to move relative to the still static remainder of South America and Africa, and this westward movement lasted until the Early Cretaceous 126.7 Ma. From there rifting propagated northward during the Late Jurassic c. 150 Ma or Early Cretaceous c. 140 Ma most likely forcing dextral movements between sub-plates on either side. South of the Walvis Ridge and Rio Grande Rise the Paraná and Etendeka magmatics resulted in further ocean-floor spreading c. 130 to 135 Ma and the development of rifts systems on both continents, including the Central African Rift System and the Central African Shear Zone which lasted until c. 85 Ma. At Brazilian latitudes spreading is more difficult to assess because of the lack of palaeo-magnetic data, but rifting occurred in Nigeria at the Benue Trough c. 118 Ma. North of the Equator the rifting began after 120.4 Ma and continued until c. 100 to 96 Ma.[33]
Madagascar Madagascar (/ˌmædəˈɡæskər/; Malagasy: Madagasikara), officially the Republic of Madagascar (Malagasy: Repoblikan'i Madagasikara [republiˈkʲan madaɡasˈkʲarə̥]; French: République de Madagascar), and previously known as the Malagasy Republic, is an island country in the Indian Ocean, off the coast of East Africa. The nation comprises the island of Madagascar (the fourth-largest island in the world), and numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from the Indian peninsula around 88 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, Madagascar is a biodiversity hotspot; over 90% of its wildlife is found nowhere else on Earth. The island's diverse ecosystems and unique wildlife are threatened by the encroachment of the rapidly growing human population and other environmental threats.