How did Madagascar become an island?

Madagascar's separation from mainland Africa is a result of the complex geological processes that occurred during the breakup of the supercontinent Gondwana. Here's a simplified overview of the events:

1. Gondwana's Formation: Around 200 million years ago, Gondwana was formed as a large landmass that included Africa, South America, Antarctica, Madagascar, India, and Australia.

2. Continental Drift: Over time, tectonic plate movements caused the gradual breakup of Gondwana. Around 180 million years ago, the first rift between Africa and Madagascar started to develop.

3. Rifting: The rifting process continued for millions of years, creating a widening gap between Africa and Madagascar. Magma from the Earth's mantle welled up into the rift valley, forming new oceanic crust.

4. Separation: Approximately 88-100 million years ago, Madagascar completely separated from Africa as the continental drift widened the Mozambique Channel. The newly formed Indian Ocean basin contributed to the isolation of Madagascar.

5. Volcanic Activity: Madagascar experienced significant volcanic activity during this period, leading to the formation of mountainous regions and plateaus. These geological processes shaped the island's topography and created its distinct landscape.

It's important to note that the timeline presented here is approximate and subject to ongoing scientific research. The geological events that led to Madagascar's separation were influenced by various factors such as plate tectonics, mantle dynamics, and seafloor spreading.