Fossil Coral

Madagascar's fossil corals represent an invaluable resource for understanding the evolutionary history of marine life and the island's geology. They were buried under sediments during the Cretaceous era, about 65 million years ago, when they were part of coral reefs. Over the years, scientists have carried out numerous studies of Madagascar's fossil corals, using radiometric dating techniques, microscopy and chemical analysis to reconstruct their evolutionary history. One of the most interesting findings was the discovery that Madagascar's fossilized corals were very different from present-day coral reefs. In fact, many of Madagascar's fossil coral species have become extinct over time, while others have evolved into completely different forms.For example, the fossilized coral genus Dendrophyllia, which occurs in large numbers in the Mahajanga Formation, is today represented by a few living species found in deep water. In the past, however, these corals were widespread in the shallow waters of Madagascar and other parts of the world. In addition, the scientists found that Madagascar's fossil corals were affected by environmental factors such as water temperature, water quality, and the presence of predators and parasites. Some species of fossil corals have features that suggest a defense against predators, such as protective spines or protuberances.Madagascar's fossil corals are also a valuable source of information about the island's geology. The Mahajanga Formation, dating from the Upper Cretaceous period, about 70-80 million years ago, is Madagascar's main source of fossil corals. It is composed of various sedimentary rocks, including sandstones, limestones and marls, which contain the remains of marine organisms, including corals, ammonites, belemnites and other molluscs. The study of fossil corals allows us to better understand the processes of evolution, the impact of environmental changes on marine life and on the formation of sedimentary rocks.