How were the Fiji islands formed through volcanic activity, sediment deposits, and coral formations?

The Fiji islands possess a complex geologic history, originating from a submerged platform of ancient formation. Their physical structure is primarily the result of three distinct processes:1

• Volcanic Action: The majority of the islands, including major landmasses like Viti Levu and Vanua Levu, are volcanic in origin. These islands feature rugged mountain ranges, such as the central range on Viti Levu, which contains numerous inactive volcanoes and the country's highest peak, Tomanivi.12
• Sedimentary Deposit: Along with volcanic activity, the accumulation of sedimentary deposits has played a significant role in shaping the islands' landmasses.1
• Coral Formations: The islands are bounded by extensive coral reefs, offshore rocks, and shoals. These formations contribute to the complex topography of the region, with reef structures evolving over time through the growth of reef-building organisms and fluctuations in sea level.13

Together, these geological forces created the diverse landscape of the Fiji archipelago, which encompasses approximately 300 islands scattered across the Pacific Ocean.14