Ancient island: A groundbreaking discovery has revealed the existence of a large. скачать в хорошем качестве

Ancient island: A groundbreaking discovery has revealed the existence of a large.

A groundbreaking discovery has revealed the existence of a large, ancient island, roughly the size of Iceland, now submerged beneath the Atlantic Ocean. Located on the Rio Grande Rise (RGR), an oceanic extension 1,200 kilometers off the Brazilian coast, the island's existence was confirmed through research published in Scientific Reports. A 2018 expedition by Brazilian and British scientists on the RGR provided the evidence. Using autonomous underwater vehicles, they meticulously mapped the seabed and collected volcanic rock and clay sediment samples. The crucial finding was the presence of red clay at approximately 600 meters depth, a material indicative of tropical soil and subaerial exposure. This red clay suggests that the Rio Grande Rise was above sea level around 45 million years ago during the mid-Eocene, forming an island potentially spanning thousands of square kilometers due to significant volcanic activity. This island underwent terrestrial erosion and weathering before gradually subsiding and drifting westward. The research highlights that submerged oceanic plateaus in the South Atlantic could have been exposed and eroded in the recent geological past, altering the geological understanding of these formations. Brazil has recently sought to extend its continental shelf to include the mineral-rich Rio Grande Rise, prompting further investigation into the island's precise extent and its potential inclusion within Brazilian territory. Subsequent research aims to definitively map the island's boundaries and understand the formation of the red clays, which are estimated to have formed under tropical conditions between 30 and 40 million years ago, following the last recorded volcanic activity 45 million years ago.