The earth has an age-old habit of burying the past, the churning of oceans and the folding of lands - hides a vast ancient secret beneath. The scientists will soon give us a glimpse of what was once above the surface with an 'Ancient Atlas'.
The earth's surface have layers of slabs and plates piled above and beside each other. A tectonic movement creates collision between and among these slabs. Some goes up, some goes under. For 4.5 billion years, the earth has been moving and violently at times. It's unimaginable how many oceans and mountains have gone deep into the earth's mantle.
“Every day, we’re losing geologic information from the face of the Earth,” says Jonny Wu, a geologist at the University of Houston in Texas.
Thanks to our advancing technology, scientists have now began peering into the deep recesses of the earth's mantle which we otherwise do not have any means of getting a glimpse of. Scientists will be using tomography techniques. The technique will create an image of earthquake waves passing through Earth’s interior. Past tomographic techniques have shown how these slabs and heaps of rocks slowly came to rest just above Earth’s molten core, 2900 kilometers below.
Salto del Fraile Formation in Peru was caused by the Andean mantle deformation
Geologist at Utrecht University in the Netherlands led by Douwe van Hinsbergen will present their 100 catalog of subducted plates at a meeting of the American Geophysical Union in San Francisco, California next month.
Some geologists shared the uncertainties posed in using seismic waves in mantle tomography. Relying on millions of seismic waves from sensors all over the world that could get indistinct as they pass through near the core or when they travel in great distances, could provide irregular data.
Academic groups around the world use more than 20 models to interpret tomographic data, and their pictures of the mantle and its structures often conflict, says Grace Shephard, a postdoc at the University of Oslo. She planned to publish her own data that could possibly conflict with the Ultrecht findings.
The good news about seismic tomography is that images have greatly improved. They used to see the subducted slabs like deformed blobs but now results have shown that plunging slabs were "stiff, straight curtains", says John Suppe, who heads the Center for Tectonics and Tomography at the University of Houston. He added that the 500-kilometre thick slabs flex but don't crumple.
The slab-driven mantle reconstruction would resurrect ocean slabs and ancient mountains. It could even look at closely how volcanoes were formed.
Van Hinsbergen and his Utrecht team hope their comprehensive atlas of slabs will make it possible to reconstruct a fuller picture of ancient geography.
The study is published in Science