Pontus Plate, a long lost tectonic with a size at least a quarter of the modern Pacific Ocean, was discovered by geologists from pieces of evidences discovered in Palawan and Borneo. (Image from Ban de Lagemaat & Van Hinsbergen / Gondwana Research)

Geologists from Utrecht University in Netherlands are claiming to have discovered a massive, previously unknown tectonic plate based on the remnants found in the mountains of Borneo and Palawan.

The existence of the newfound tectonic plate, Pontus, named after the Greek sea deity, had long been hypothesized by geologists to be in the western Pacific region but lacked precise location data.

“Eleven years ago, we thought that the remnants of Pontus might lie in northern Japan, but we’ve since refuted that theory. It was only after Suzanna had systematically reconstructed half of the Ring of Fire mountain belts from Japan, through New Guinea, to New Zealand that the proposed Pontus plate revealed itself, and it included the rocks we studied on Borneo,” said Utrecht University Professor of Global Tectonics and Paleogeography Douwe van Hinsbergen.

Suzanna van de Lagemaat’s doctoral dissertation focused on reconstructing the movements of tectonic plates in the region stretching from Japan to New Zealand over the past 150 million years. Her reconstruction revealed a significant gap between the Australian, Eurasian, Indian, and Pacific Plates, raising questions about the existence of a missing tectonic plate to complete the puzzle.

Blending computer simulations and conducting field research across diverse terrains, including the mountainous regions of Japan, New Zealand, New Guinea, Borneo, and Southern Palawan in the Philippines, Van de Lagemaat discovered the existence of another tectonic plate that once covered approximately a quarter of the modern Pacific Ocean’s size around 150 million years ago.

A video reconstruction of the Pontis Plate based on the dissertation of Suzanna van de Lagemaat. (Video from Gondwana Research)

The rocks discovered in Borneo and Palawan confirmed the existence of the Pontus Plate.

As tectonic forces pushed the paleo-Pacific westward, the Pontus Plate eventually subducted beneath the Eurasian Plate, and fragments of its seafloor were thrust onto land, forming part of the mountain ranges we see today.

Geologist Suzanna van de Lagemaat from Utrecht University conducts field study in Palawan and Borneo. (Photo from Suzanna van de Lagemaat)

“We also conducted field work on northern Borneo, where we found the most important piece of the puzzle. We thought we were dealing with relics of a lost plate that we already knew about. But our magnetic lab research on those rocks indicated that our finds were originally from much farther north, and had to be remnants of a different, previously unknown plate,” Van de Lagemaat said

This discovery not only contributes to our understanding of Earth’s geological history but also highlights the unique geological context of the Palawan and the Philippines, where parts of the Pontus Plate were found.

“The Philippines occupies an intricate intersection of various tectonic plate systems. The region predominantly comprises oceanic crust, yet some fragments emerge above sea level, displaying rocks of varying ages,” she said.