WASHINGTON: Scientists have discovered huge rock formations in Greenland, which they believe are remnants of Earth's crust created when the sea floor split apart some 3.8 billion years ago.
The finding shows that the process called plate tectonics, or splitting of the Earth's crust, had been occurring right from the beginning of the planet's history.
Scientists describe plate tectonics as a process where the Earth's crust is constantly formed at spreading ridges in the oceans as the plates separate themselves in areas called subduction zones. The material from the sinking plate can get disentangled on to the edge of a stationary plate. In some cases, the subduction zones get jammed and the pieces of the sea floor get pushed up to the continent above instead of getting recycled below. The new rocks found in Greenland have come into existence through this process, the scientists believe.
The tectonic plates are known to move vast distances over millions of years. When they come together there are known geological activities like earthquakes, volcanic eruptions and even creation of mountain ranges.
The rocks have been found in the Isua Belt, in southwest Greenland. A team of geologists led by Harald Fumes of the University of Bergen in Norway has studied these rocks and the details of the team's research have been published in the journal Science.
Fumes said these ancient rocks found in southwestern Greenland were formed on the sea floor of primordial Earth. They were made from thin sheets of molten rock and resembled a multilayered cake. The contents included a mix of volcanic rocks involved in the formation of new crust.
The Earth is about 4.5 billion years old and scientists differ on whether plate tectonics was happening in the early days of the planet. This discovery may throw some fresh light into the mystery.
Fumes says these rocks are not the oldest known ones on Earth as rocks dating back to 4.2 billion years have been found in Canada.
The scientists say the structures and processes in plate tectonics in ancient days could be similar to the modern period, but there are differences, one of them being that Earth was much hotter then than now and as it cooled, it put many of the tectonic processes into overdrive.
