Bizarre rock forms under the Pacific may be the clue to Earth's history, says new study

Our planet's history spans billions of years, with many mysteries still to be unlocked about its formation. Recently, researchers discovered an incredible window into Earth's past beneath the Pacific Ocean. A study titled "Large-scale submarine landslides in the Barberton Greenstone Belt, southern Africa—Evidence for subduction and great earthquakes in the Paleoarchean," published by the Geology Journal, reveals some shocking truths about ancient Earth. 

Geologists, so far, have found it difficult to decode rock formations in the Barberton Greenstone Belt in South Africa. However, a new correlational study comparing these structures to those formed on the seafloor of the Pacific Ocean off the coast of New Zealand gave a better perspective on our planet's history. This research, led by Simon Lamb and Cornel de Ronde, was initiated when de Ronde mapped a new, detailed geological layout of part of the Barberton Greenstone Belt. This mapping revealed a portion of the deep-sea floor over 3.3 billion years ago. Considering the peculiarity of this segment of ancient structure, the study's authors associated it with the rocks studied in the seabed of the Pacific Ocean on New Zealand's coast, as explained in The Conversation.

Contrary to the belief that ancient Earth was hotter with a weak surface devoid of earthquakes, these structures showed signs of massive quakes billions of years ago. The rocks in the Barberton Greenstone Belt have puzzled researchers for a long. The rocks had "beautiful crystals of barite" or "the remains of bubbling mud pool" on top. They found several haphazard layers of blocks of volcanic rocks, chert and sandstones too. These weird rock formations posed a striking similarity to the submarine landslides studied in New Zealand's largest fault in the Hikurangi subduction zone.

Though the bedrock formed through sedimentation in New Zealand's coast was a recent one dating back to 20 million years ago, it was the clue to deciphering South Africa's strange structures. The once "untranslatable" rock formations were now identified to be "a remnant of a gigantic landslide containing sediments deposited both on land or in very shallow water." These remnants were clustered with the sediments on the deep sea floor, forming an unusual appearance and composition. The key to these findings emerged from the perpetual effects of earthquakes in a subduction zone in New Zealand, which mimics the historical occurrences from over 3 billion years ago. One of the recent instances was the 2016 Kaikoura earthquake that created major deep-sea landslides.

Also, this research ended up unraveling more mysteries apart from the one about the Barberton Greenstone Belt. The monstrous eruption of Tonga's Hunga Tonga-Hunga Ha'apai volcano in 2022 had many underwater volcanoes erupting in the same region. These underwater volcanoes erupted an unusual type of lava called "boninite," which used to be the common form of lava during Earth's early days. Scientists believe that the Barberton Greenstone Belt could also have faced such "volcanic violence," involving lightning strikes that triggered the creation of basic organic molecules, thus bringing life to Earth.