(CN) – The British mainland came out of the collision of three ancient continental land masses, not two as previously thought according to new research published Friday in Nature Communications.
Geologists at University of Plymouth, England, conducted an extensive study of mineral properties at exposed rock features across the counties of Devon and Cornwall. They found northern areas share their geological roots with the rest of England and Wales, while everything south is geologically linked to France and mainland Europe.
In light of the findings, scientists now believe the ancient tectonic plates of Armorica also merged along with those of Avalonia and Laurentia more than 400 million years ago to create England, Wales and Scotland.
"This is a completely new way of thinking about how Britain was formed,” according to Arjan Dijkstra, lead author and lecturer in igneous petrology.
“It has always been presumed that the border of Avalonia and Armorica was beneath what would seem to be the natural boundary of the English Channel. But our findings suggest that although there is no physical line on the surface, there is a clear geological boundary which separates Cornwall and south Devon from the rest of the U.K.,” he said.
Among other things, scientists believe the research explains the abundance of tin and tungsten in the far southwest of England – matching metals also found in Brittany, France and other areas of the European mainland – but not readily found in the rest of the British Isles.
For the research, Dijkstra and then-student Callum Hatch visited 22 sites in Devon and Cornwall. Each site encompassed an area left exposed some 300 million years ago by geological events, such as underground volcanic eruptions that brought magma to the Earth's surface.
The researchers used X-ray fluorescence spectrometry to conduct a detailed chemical analysis of rock samples from each site. They then dissolved the samples in acid to conduct a more intensive isotopic analysis of the levels of the two elements, strontium and neodymium, to understand the full history of the rocks.
These findings were then compared with previous studies elsewhere in Britain and mainland Europe, with the results showing the clear boundary running from the Exe estuary on the south coast of Devon in the east to the Cornwall town of Camelford in the west.
"We always knew that around 10,000 years ago you would have been able to walk from England to France," Dijkstra added. "But our findings show that millions of years before that, the bonds between the two countries would have been even stronger. It explains the immense mineral wealth of southwest England, which had previously been something of a mystery, and provides a fascinating new insight into the geological history of the U.K."
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