Ancient Tectonic Plates That Were Lost Found in Kalimantan

Geologists discovered that oceanic remains in northern Kalimantan are believed to come from a long-lost ancient plate called Pontus.

The following article was translated using both Microsoft Azure Open AI and Google Translation AI. The original article can be found in Lempeng Tektonik Purba yang Sempat Hilang Ditemukan di Kalimantan

UTRECHT UNIVERSITY

Pontus, an ancient tectonic plate, was discovered in the northern region of Kalimantan.

JAKARTA, KOMPAS - Geologists have reconstructed a quarter of the missing and previously unknown large tectonic plate in the Pacific Ocean. The reconstruction revealed that the remnants of an ocean in Northern Kalimantan are believed to originate from an ancient plate named Pontus, which had long been lost.

The reconstruction related to this large lost tectonic plate was carried out by researchers from Utrecht University, Netherlands, and led by geologist Suzanna Van de Lagemaat with a report published in Elsevier, 29 September 2023. Lagemaat reconstructed an ancient plate that was lost this through field research and detailed observations in the mountain belts of Japan, Kalimantan, the Philippines, Papua New Guinea and New Zealand.

Van de Lagemaat discovered that the remnants of the ocean in northern Kalimantan are believed to originate from the Pontus Plate. Pontus is a region on the southern coast of the Black Sea that is currently located in modern-day Turkey. This area was once famous for its fertility.

We also conducted field research in northern Kalimantan, where we found the most important piece of the puzzle.

Van de Lagemaat is studying the most complicated tectonic plate area on Earth, which is in the region around the Philippines. "The Philippines is located at the intersection of complex systems of different plates. This area is almost entirely made up of oceanic crust. However, some parts of it are lifted above sea level and show rocks with vastly different ages," he said as quoted from Utrecht University's official website on Sunday (22/10/2023).

Understanding the movement of tectonic plates that form the Earth's rigid outer layer is crucial to understanding geological history. The movement of these plates greatly influences changes in paleogeography and the planet's climate over time.

However, large ancient oceanic tectonic plates have disappeared into the Earth's mantle through subduction. These plates only leave behind hidden rock remnants in mountain belts. This is what underlies Van de Lagemaat's study of these plates.

Van de Lagemaat is the first person to reconstruct the current movement of tectonic plates in the region between Japan and New Zealand using geological data. The reconstruction result reveals that the missing plates in the western Pacific region have a very large area.

Also read: Revealing the Amazing Traces of Plate Movement

"We also conducted field research in Northern Kalimantan, where we discovered the most important part of the puzzle. We believe that we are dealing with a lost plate relic that we already know," he said.

However, magnetic laboratory research on the rock shows that the researchers' findings come from a region in the north and are believed to be the remnants of another plate that was previously unknown.

SUCIPTO

The article to be translated is as follows: "The unique paddy fields landscape of Krayan can be found in Long Midang Village, Krayan District, Nunukan Regency, North Kalimantan, on Saturday (27/11/2021)." Translation: The exceptional rice paddies landscape of Krayan is situated in Long Midang Village, Krayan District, Nunukan Regency, North Kalimantan, on Saturday (27/11/2021).

Douwe van Hinsbergen, who is the doctoral study supervisor (PhD) of Van de Lagemaat, stated that 11 years ago researchers estimated that the remains of Pontus were located in the northern part of Japan. However, they later refuted the theory.

The Suspected Pontus Plate was recently uncovered after Suzanna Van de Lagemaat systematically reconstructed half of the Pacific Ring of Fire mountain belt from Japan through Papua New Guinea to New Zealand. This also includes rocks that we studied in Kalimantan," she disclosed.

Legacy trail

The trace of Pontus's legacy is not only located in the northern part of Kalimantan, but also in Palawan, an island in Western Philippines and the South China Sea. This research also shows that a single coherent tectonic plate system stretches from southern Japan to New Zealand. The system has existed for at least 150 million years.

Previous predictions about the existence of Pontus may be possible due to subduction plates leaving a trace when they sink into the Earth's mantle. This anomaly can be observed when seismographs capture earthquake signals.

An earthquake then sends waves through the inner part of the Earth. When the waves propagate through an anomaly like an old tectonic plate fragment, the anomaly then produces disturbances in the signal.

Also read: Collision of Three Plates in the Shape of the Letter K on Sulawesi Island

Geologists can trace the disruption to the existence of phenomena within the mantle such as broken tectonic plates. This enables researchers to see events 300 million years ago, particularly related to ancient plate fragments at the boundary between the mantle and core.

A research conducted 11 years ago showed that a large subduction zone is believed to cross the western part of the Paleo-Pacific Ocean, separating the Pacific Plate. This zone is known to be located to the east of the hypothesized Pontus plate in the west. This hypothesis has now been independently proven by Van de Lagemaat's research.