MADRID (EP) — A team of thirty scientists has completed a nine-week expedition to study Zealandia, a submerged continent in the Pacific Ocean, which occupies an area comparable to India.
The expedition was organized aboard the research vessel JOIDES Resolution by the International Ocean Discovery Program (IODP), a collaboration involving scientists from 23 countries aimed at investigating Earth's history recorded in sediments and rocks beneath the seafloor.
Jamie Allan, director of the Ocean Sciences Division at the U.S. National Science Foundation, which supports the IODP, stated, "Zealandia, a long-lost sunken continent, is revealing its secrets from 60 million years ago through scientific ocean drilling."
Allan added, "This expedition provided insights into Earth’s history, ranging from the formation of mountain ranges in New Zealand to tectonic plate movements and changes in ocean circulation and global climate."
Earlier this year, Zealandia was confirmed as the seventh continent of Earth, but little is known about it due to its submersion over a kilometer below sea level. The region has been sparsely surveyed and sampled until now.
The scientists drilled deeply into the seabed at six sites, reaching depths of over 1,250 meters, and collected 2,500 meters of sediment cores that record how Zealandia's geography, volcanism, and climate have changed over the past 70 million years.
According to chief expedition scientist Gerald Dickens from Rice University, significant fossil discoveries were made, indicating Zealandia was not always submerged as it is today. "Over 8,000 specimens were studied, and several hundred fossil species were identified," Dickens noted. "The discovery of microscopic shells from organisms that lived in warm, shallow seas, as well as spores and pollen from terrestrial plants, reveals that Zealandia's geography and climate were dramatically different in the past."
These new findings demonstrate that the formation of the Pacific Ring of Fire, an active marine zone along the Pacific Ocean's perimeter, approximately 40 to 50 million years ago, caused dramatic changes in ocean depth, volcanic activity, and altered the seabed of Zealandia, according to Dickens.
Rupert Sutherland, a scientist from Victoria University of Wellington in New Zealand, explained that researchers previously believed Zealandia was submerged when it separated from Australia and Antarctica about 80 million years ago. "That is probably accurate, but it is now clear that dramatic subsequent events shaped the continent we explored on this journey," Sutherland said. "The significant geographical changes throughout northern Zealandia, which is roughly the size of India, have implications for understanding how plants and animals dispersed and evolved in the South Pacific."
He added, "The discovery of past land and shallow seas now provides an explanation, and there were pathways for animals and plants to move."
Future studies of the sediment cores obtained during the expedition will focus on understanding how Earth's tectonic plates move and how the global climate system functions.