Unveiling Zealandia: The Eighth Continent’s Ancient Journey from Gondwana to Submersion

Read about the Zealandia, the 8th continent, when will it rise, its discovery and when it sunk here.

Approximately 23 million years ago, the eighth continent of our world underwent a nearly complete submersion beneath the ocean’s surface. This dramatic event occurred roughly 60 million years after it had separated from the supercontinent Gondwana.

For a while, geologists had recognized the geological similarities between New Zealand and New Caledonia. However, after extensive exploration and research, it became evident that these regions shared more than just geological features; they actually rested upon the same submerged landmass. While we often associate continents with vast land areas like Asia or Europe, a group of geologists asserted in 2017 that the mass of continental crust they named “Zealandia” was most appropriately categorized as its own distinct continent in geological terms.

Zealandia’s continental crust, constituting approximately 94 percent of its landmass, now lies beneath the ocean’s surface, with notable exceptions being New Zealand, New Caledonia, and a few smaller islands. Though thinner than the crust of most continents, Zealandia’s crust is thicker than typical oceanic crust. It was formed during the gradual breakup of Gondwana, characterized by the thinning and stretching of its crust.

The specific processes that led to this thinning remained a mystery, prompting a new team to undertake an investigation. They conducted analyses on samples collected from Zealandia, creating maps and models of the continent while also examining magnetic anomalies.

In their research paper, the team explained, “We believe Zealandia is the first of Earth’s continents to have its basement, sedimentary basins, and volcanic rocks fully mapped out to the continent-ocean boundary.”

According to their findings, extensive thinning of Zealandia’s crust occurred from 100 to 80 million years ago, likely due to stretching in various directions, eventually leading to the continent’s submersion beneath the ocean.

Despite its current submerged state, Zealandia provides evidence of its past as a thriving environment for a diverse range of plants and animals. This evidence includes spores of pollen from terrestrial plants and the remains of shallow-water creatures, now discovered deep beneath the ocean’s surface.

It’s worth noting that during the breakup of Gondwana, plant and animal species managed to survive, ultimately leading to the formation of continents such as South America, Africa, Arabia, Madagascar, India, Australia, and Antarctica. The revelation that Zealandia originated from this ancient breakup helps shed light on the movements and evolution of plants and animals in the South Pacific region.

Rupert Sutherland, a co-author of the 2017 study that initially recognized Zealandia as a continent, commented, “Significant geographical changes across northern Zealandia, a landmass roughly equivalent in size to India, offer insights into questions related to the dispersion and evolution of plants and animals in the South Pacific. The discovery of past land and shallow seas now provides an explanation, revealing pathways for the movement of animals and plants.”