The new theory, which is already supported by a large group of geologists and paleontologists, is based on an analysis of microfossil assemblages found inside the cores that were drilled deep into sediments on the ocean floor, notes Science Daily.
Quite possibly, there were two such volcanic eruptions and mantle plumes with one occurring several million years before the second. It would have been the second mantle plume that led to the extinction of the dinosaurs.
What is a mantle plume? Think lava lamp. A mantle plume is caused by rising and mushrooming hot mantle from deep within the Earth. Just like a lava lamp would do, the heat rises up, then mushrooms out, and finally flattens. The mantle plume eruptions, which spread magma over the Earth's surface in a diameter of 620 miles, last between 1 million and 2 million years.
There are seven huge remnants of such mantle plumes, all of which are still considered "hotspots" today and are responsible for volcanic activity. They are in Iceland, the islands of Hawaii, Easter, Reunion, Tristan, and Louisville, as well as the Afar region of Ethiopia.
Mantle plumes "are a catalyst for the formation of ocean basins and fundamentally reshaping the Earth's surfaces. The massive outpouring of lava, ashes, and gas can have significant effects on climate, which destabilizes the environment and have the potential to dictate the course of evolution," said Dr. Andrew Kerr of Cardiff University's School of Earth, Ocean and Planetary Sciences in a news release announcing the study. "It is likely that were it not for mantle plumes, mammals would not have become predominant, and humankind would not be here today."
