The biggest example of volcanic activity of the last 300 million years, could not have been caused by a meteorite. About 120 million years ago, about 1% of the Earth for 7 million years there were volcanic eruptions. It was in the Pacific, the site of the present-Ontong Java Plateau, which was formed as a result and.
The hypothesis of a meteorite launched long ago. For verification team analyzed Gorgo rock-a-Cherbara in central Italy at the time connected to the scope of the eruption.
The researchers focused on platinum group elements, ie platinum, iridium, ruthenium, rhodium, palladium, osmium, which have similar physical and chemical properties. These elements are more abundant in meteorites than in the Earth's crust, and their presence may therefore be a sign of extraterrestrial impact. Plays the role of the concentration and the ratio of these elements to each other. Thus, platinum and iridium are related as 2:1 in the rocks of extraterrestrial origin.
The analysis did not find any evidence of meteorite hypothesis. "The results so far show that this event was caused by internal processes," — says study coauthor Marissa Tejada of the Japan Agency for Marine-Earth Science and Technology. Land saw many eruptions, which seems to have been caused solely by internal factors.
What is it? The answer to this question should be a study of other species of the Pacific and North America.
The study is published in the journal Scientific Reports.