Whose studies first explained how volcanoes create new islands?

Charles Darwin's observations during the voyage of HMS Beagle helped clarify how volcanic islands can form and evolve. While his most famous work is on evolution, he also made major geological contributions, especially on coral reefs and island subsidence. He recognized that volcanic islands can rise from the ocean floor and later sink, while reefs grow upward around them. This helped scientists understand island chains and atolls in the context of slow geological change. Darwin's geological insights were part of the broader 19th-century revolution in Earth science.