New theory posits that Iceland may be tip of a long-lost sunken continent, Icelandia - National Post

Rabu, 04 Agustus 2021

New theory posits that Iceland may be tip of a long-lost sunken continent, Icelandia - National Post

The continent, experts suggest, may have once stretched between Greenland and Europe before swathes of it sunk under the waves 10 million years ago

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National Post Staff

Reynisfjara beach in Iceland. Photo by Getty Images

Iceland may be the remnant tip of a long-lost ancient sunken continent, suggests a wild new theory posited by an international group of geophysicists and geologists.

The continent — dubbed Icelandia by several academics — may have once stretched more than 600,000 sq. km between Greenland and Europe before sinking under the ocean 10 million years ago, reads a chapter in a 2021 book In the Footsteps of Warren B. Hamilton: New Ideas in Earth Science (Geological Society of America, 2021) that describes the new theory.

If experts were to include submerged areas west of Britain and Ireland into ‘Greater Icelandia’, the area of the continent could exceed 1 million square kilometres in size.

The chapter was co-written by Dr. Gillian Foulger, a geophysics professor at Durham University in the U.K.; Dr. Laurent Gernigon of the Geological Survey of Norway; and Laurent Geoffroy, a tectonics expert at the Ocean Geosciences Laboratory, University of Brest in France.

The theory, if proven, would contradict long-held scientific notions around the oceanic and continental crust in the North Atlantic region and how Iceland was formed.

“Until now Iceland has puzzled geologists, as existing theories that it is built of and surrounded by oceanic crust are not supported by multiple geological data. For example, the crust under Iceland is over 40 km thick — seven times thicker than normal oceanic crust. This simply could not be explained,” Foulger said in a Phys.org report.

The ancient continent of Icelandia once extended from Greenland to Europe, a new theory suggests.Reynisfjara beach in IcelandReynisfjara beach in Iceland Photo by Gillian Foulger

Until now, scientists assumed that the North Atlantic region was formed after the supercontinent Pangaea began to break up 200 million years ago. Iceland was eventually formed about 60 million years ago above a volcanic plume near the centre of the ocean.

However, Foulger pointed out that the sunken continental crust that would have made up Icelandia is “still standing higher than it should.” “If the sea level dropped 600 meters [2,000 feet], then we would see a lot more land above the surface of the ocean,” Foulger told Live Science.

Foulger and her co-authors posited a new theory: As Pangaea split, oceans began to form roughly south and north of Iceland, but not east and west.

The areas to the east and west, the geologists say, are still connected to modern-day Greenland and Scandinavia, suggesting that the ancient supercontinent has not fully broken apart.

“People have this highly simplistic idea that a tectonic plate is kind of like a dinner plate: It just splits in two and moves apart,” Foulger said. “But it’s more like a pizza, or a piece of artwork made from different materials – some fabric here and some ceramic there, so that different parts have different strengths.”

The theory, geologists say, would explain why the crust under modern Iceland are 40 km thick instead of 5 km thick, which would have supported the explanation that Iceland had formed over a volcanic plume.

“When we considered the possibility that this thick crust is continental, our data suddenly all made sense,” Foulger said in a statement.

“This led us immediately to realize that the continental region was much bigger than Iceland itself – there is a hidden continent right there under the sea.”

Fossil evidence, according to authors, also reinforce the existence of Icelandia — some plants that spread by dropping seeds could be found in both Greenland and Scandinavia, supporting the notion that the two regions were once connected.

Geologists, however, have not yet found fossil evidence of animals on the lost continent.

If true, the new theory of Icelandia could pose profound implications for the extraction of fossil fuels beneath the sea floor.

Under international law, any country that can prove the resources lie beneath their continental shelf can lay claim to the fuels.

Geographer Philip Steinberg, director of Durham University’s Centre for Borders Research, told Live Science that several countries are spending large amounts of money on research to prove that they have exclusive mineral rights beneath their continental shelves.

“Research like Professor Foulger’s, which forces us to rethink the relationship between seabed and continental geology, can have far-reaching impact for countries trying to determine what area of the seabed are their exclusive preserve,” Steinberg said in the statement.

The idea of a sunken, lost continent could significantly alter “our geological understanding of the world,” Foulger said.

“Something similar could be happening at many more places. We could eventually see maps of our oceans and seas being redrawn as our understanding of what lies beneath changes.”

However, other experts have rejected the theory, claiming little evidence supports it.

Ian Dalziel, a geologist at the University of Texas of Austin, told Live Science there was not enough continental crust material in the North Atlantic region to have formed Icelandia.

Geophysicists Carmen Gaina, director of the Centre for Earth Evolution and Dynamics in Oslo, and Alexander Minakov of the University of Oslo also told Live Science that the existence of Icelandia was unlikely as the proposal was a “bold claim” with several problems.

One problem, they explained, was that the magnetic surveys of the seafloor in the region show “stripes” that show when successive molten crust layers accumulated on the North Atlantic sea floor, as a result of the Earth’s magnetic field switching its polarity over million years. This is a clear sign of ocean crust also observed in large oceanic plateaus in the Pacific Ocean, they said.

The “conceptual view” of the idea however, could be a “good starting point for discussions and more importantly, for more and relevant data collection, they acknowledged.

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2021-08-04 18:02:28Z
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Tva Ganir

Rabu, 04 Agustus 2021