Scientists are gaining a deeper understanding of Earth's geology through the comprehensive mapping of Zealandia, a vast, submerged continental fragment in the South Pacific Ocean. This process, which has been ongoing with a goal to complete by January 2025, has revealed significant details about this portion of the ancient supercontinent Gondwana.
Zealandia covers an area of approximately 1.9 million square miles, with about 95% of its landmass lying beneath the ocean's surface. The continent's separation from Gondwana occurred between 85 and 60 million years ago, a process marked by extensive volcanic activity. By approximately 25 million years ago, Zealandia reached its peak submergence, a period that contributed to the formation of New Zealand's North and South Islands. Recent mapping efforts have uncovered new details about Zealandia's geological past, including the discovery of its ancient granite backbone, known as the Median Batholith, estimated to be between 250 and 100 million years old. The continent's crust is notably thinner than that of most other continents, a characteristic attributed to extensive stretching and thinning processes during its separation from Gondwana. These discoveries provide invaluable insights into the migration patterns of flora and fauna across the South Pacific and the complex tectonic processes that shaped the region.