120-Million-Year-Old Fragment of Earth from Pangea Breakup Discovered

Scientists have recently uncovered a 120-million-year-old section of Earth’s crust in Borneo that had long been considered lost. The discovery of this ancient tectonic plate, named Pontus, was made by Suzanna van de Lagemaat, a geologist from Utrecht University in the Netherlands, along with her supervisor Douwe van Hinsbergen. The finding emerged during their analysis of geological data from mountain ranges in the Asia-Pacific region.

Van de Lagemaat identified remnants of the Pontus plate while examining rock formations in Borneo. “Initially, we thought we were dealing with remains of a previously known lost plate. However, our magnetic lab research on these rocks revealed that they originated much farther north, indicating that we had discovered a previously unknown plate,” she explained.

To further investigate the Pontus plate, Van de Lagemaat focused her research on a geologically complex area known as the Junction Region, which includes Japan, Borneo, the Philippines, New Guinea, and New Zealand.

 

Size and History of the Pontus Plate

Using a range of data collected during her research, Van de Lagemaat reconstructed the movements of tectonic plates in the region dating back to the time of the dinosaurs. It was determined that the Pontus plate was part of Earth’s crust before the supercontinent Pangaea began to break apart.

Based on these reconstructions, scientists estimated that the Pontus plate was approximately a quarter of the size of the Pacific Ocean around 160 million years ago. At the time, a large ocean separated Eurasia and Australia, with the Pontus plate located beneath this ocean. As Pangaea fragmented, the Pontus plate was absorbed by surrounding tectonic plates, which now form parts of the Philippines and Borneo.

Borneo, the world’s third-largest island and part of the Greater Sunda Islands in Southeast Asia, is politically divided between Malaysia, Brunei in the north, and Indonesia in the south.