The new basalt has just fallen. An international team of scientists drilled nearly a mile into the Pacific seabed and extracted a variety of chemically and mineralogically different volcanic rock of any previously known type.
The team examined a 49-million-year-old rock outcrop that formed just a couple of million years after the ring of fire, that famous crescent of volcanic activity that borders the Pacific coast. During the first million years after its ignition, the ring burst with an overheated intensity, according to the team, which formed a unique type of stone.
They collected this evidence of Earth’s history from almost 5 miles below the surface of the ocean. His analysis suggests that the fires that forged the rock were hotter and more expansive than previously thought. Their results were published last week at Nature Communications.
“The rocks we recovered are clearly different from the rocks of this type that we already know,” said co-author Ivan Savov, a geochemist and volcanologist at the University of Leeds, at a university. Press release. “In fact, they may be as different from the known ocean floor basalts of the Earth as the basalts of the Earth to the basalts of the Moon.”
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Basalt is a very common type of igneous rock that emerges from cooled lava flows, including current active volcanoes. But the pressures and temperatures from which the stones come out completely change their characteristics. The stone, according to the team, probably formed towards the end of the volatile beginnings of the Ring of Fire. It had not previously been detected due to its extremely remote (and difficult to access) location.
Although ancient, the Ring of Fire is young in terms of the tectonic history of the Earth. Some volcanic rocks date back billions of years, much older than the new rock’s 49 million years of existence.
The team drilled the sample with the Resolution JOIDES, a drilling rig capable of extracting samples from 6 miles below the surface. (At just 5 miles deep, the newly reported basalt didn’t even push the boundaries of the platform.) Under the microscope, a cross section of the stone looks like a frozen frame of a kaleidoscope, a conglomeration of slate grays. and sea greens. It comes from the Amami Sankaku Basin, about 600 miles off the coast of Japan. Savov said that knowing the conditions that formed this basalt will help Earth scientists better understand the development of the largest formation from which it was extracted.
“At a time when we rightly admire discoveries made through space exploration, our findings show that there are still many discoveries to be made on our own planet,” Savov said in the university statement.
Rocks can tell us many things about the history of the planet. Recently, scientists examining the rocks of Greenland discovered evidence of a ocean of magma which existed when the Earth was only a baby, shortly after the formation of the Moon.