A single boulder can prove that Antarctica and North America were one
A single granite boulder, despite being found high in the Antarctic glacier, can provide additional key evidence to prove the theory that the southernmost continent was one whole North America hundreds of millions of years ago.
In an article in the journal Science, released on July 11, an international team of American and Australian scientists describes the results of research that was conducted in the Transantarctic Mountains and their importance in solving the problem of reconstructing the boundaries of the ancient supercontinent called Rodinia. American researchers were funded by the National Science Foundation (NSF).
Past scientific research forced researchers to create a theory that about 600–800 million years ago a part of Rodinia separated from what is now the southwestern United States, and eventually drifted south to become East Antarctica and Australia.
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The finding of the team, according to their arguments, provides a new evidence that confirms the hypothesis of the kinship of the southwestern United States and East Antarctica (UZVAT).
“This article suggests that we have three new lines of evidence that support the YUSVAT idea,” said John Goodge, a researcher in the geological sciences department at the University of Minnesota-Duluth, funded by NSF.
Scott Borg, director of the Antarctic Science Division at the NSF Polar Programs Office, adds: “This is a great job and a great example of how scientists work out pieces of big puzzles. The authors not only structure a huge amount of data to address the long-standing issue of the development of the Earth’s crust over a long period of evolution, but also show how evidence for the HOSVAT hypothesis has evolved over time. ”
As a field researcher from the late 1980s to the early 1990s, Borg studied the HUZVAT hypothesis.
The boulder was found quite by accident, although the researchers specially collected cobblestones separated from the Transantarctic mountains because of the glaciers.
Goodge and his team were looking for rocks that could provide the key to the composition of the mainland Antarctic crust, which is mainly buried under almost two miles of ice.
“We were raising interesting looking boulders in moraines,” said Goodge. "Basically, it was just a hodgepodge."
One stone, small enough to hold it in one hand, found at the Great Hunter Glacier, was later identified as granite with, as Hooge describes it, "a specific type of coarse-grained structure."
Subsequent chemical and isotopic tests conducted in laboratories in the United States showed that the boulder had a composition “very similar to the composition of a unique igneous rock belt in North America,” which extends from what is now called California eastward through New York. Mexico to Kansas, Illinois and, ultimately, through New Brunswick and Newfoundland ends in Canada.
That belt of rocks, as is known, was located on the mainland Lawrence, which was one of the parts of the Rodinia supercontinent.
“Here the long, linear belt of these igneous rocks passes, which extends across Laurentia. But keep in mind that it stops right there in the (western) region, where, as we know, a rift occurred "in the place that is now the western coast of the United States," said Gooj.
“This unexpected end suggests that there is an ancient breed somewhere like this,” said Goodge. "And these rocks are not found in almost any other part of the world."
What was found on a glacier high in the mountains of Antarctica is convincing evidence in support of the UZVAT model, according to which the frozen continent is part of North America.
“There is no other explanation for how the boulder got to the place where we found it,” said Goodge. "It is one of the largest chips from the subglacial part of Antarctica."
The discovery itself is indisputable for geologists, said Goodge, since there are other physical evidence that allows them to combine into one piece pieces of the long-disappeared Rodinia.
Since the supercontinent existed at the time of the development of multicellular life on Earth, it will also help to provide the geological context in which this massive biotic change took place.
“During the Cambrian explosion about 520 million years ago, as we can see, there was an instant increase in the diversity of life forms,” said Goodge. "It was a time when the Earth underwent tremendous geological changes."
He added that “something helped to cause the release of a large amount of radiation.”
The continual movement of the continents, accompanied by clashes between them, erosion and the influx of chemicals into the seas, may have provided nutrients to that variety of life forms.
“There are ideas of creating links between the geotectonic world, on the one hand, and biology, on the other.
The work of specialists in earth sciences in this context, "said Goodge," must restore the general picture of the world at that distant time. "
Source: National Science Foundation
Translation of the article is made for the site magov.net
In an article in the journal Science, released on July 11, an international team of American and Australian scientists describes the results of research that was conducted in the Transantarctic Mountains and their importance in solving the problem of reconstructing the boundaries of the ancient supercontinent called Rodinia. American researchers were funded by the National Science Foundation (NSF).
Past scientific research forced researchers to create a theory that about 600–800 million years ago a part of Rodinia separated from what is now the southwestern United States, and eventually drifted south to become East Antarctica and Australia.
')
The finding of the team, according to their arguments, provides a new evidence that confirms the hypothesis of the kinship of the southwestern United States and East Antarctica (UZVAT).
“This article suggests that we have three new lines of evidence that support the YUSVAT idea,” said John Goodge, a researcher in the geological sciences department at the University of Minnesota-Duluth, funded by NSF.
Scott Borg, director of the Antarctic Science Division at the NSF Polar Programs Office, adds: “This is a great job and a great example of how scientists work out pieces of big puzzles. The authors not only structure a huge amount of data to address the long-standing issue of the development of the Earth’s crust over a long period of evolution, but also show how evidence for the HOSVAT hypothesis has evolved over time. ”
As a field researcher from the late 1980s to the early 1990s, Borg studied the HUZVAT hypothesis.
The boulder was found quite by accident, although the researchers specially collected cobblestones separated from the Transantarctic mountains because of the glaciers.
Goodge and his team were looking for rocks that could provide the key to the composition of the mainland Antarctic crust, which is mainly buried under almost two miles of ice.
“We were raising interesting looking boulders in moraines,” said Goodge. "Basically, it was just a hodgepodge."
One stone, small enough to hold it in one hand, found at the Great Hunter Glacier, was later identified as granite with, as Hooge describes it, "a specific type of coarse-grained structure."
Subsequent chemical and isotopic tests conducted in laboratories in the United States showed that the boulder had a composition “very similar to the composition of a unique igneous rock belt in North America,” which extends from what is now called California eastward through New York. Mexico to Kansas, Illinois and, ultimately, through New Brunswick and Newfoundland ends in Canada.
That belt of rocks, as is known, was located on the mainland Lawrence, which was one of the parts of the Rodinia supercontinent.
“Here the long, linear belt of these igneous rocks passes, which extends across Laurentia. But keep in mind that it stops right there in the (western) region, where, as we know, a rift occurred "in the place that is now the western coast of the United States," said Gooj.
“This unexpected end suggests that there is an ancient breed somewhere like this,” said Goodge. "And these rocks are not found in almost any other part of the world."
What was found on a glacier high in the mountains of Antarctica is convincing evidence in support of the UZVAT model, according to which the frozen continent is part of North America.
“There is no other explanation for how the boulder got to the place where we found it,” said Goodge. "It is one of the largest chips from the subglacial part of Antarctica."
The discovery itself is indisputable for geologists, said Goodge, since there are other physical evidence that allows them to combine into one piece pieces of the long-disappeared Rodinia.
Since the supercontinent existed at the time of the development of multicellular life on Earth, it will also help to provide the geological context in which this massive biotic change took place.
“During the Cambrian explosion about 520 million years ago, as we can see, there was an instant increase in the diversity of life forms,” said Goodge. "It was a time when the Earth underwent tremendous geological changes."
He added that “something helped to cause the release of a large amount of radiation.”
The continual movement of the continents, accompanied by clashes between them, erosion and the influx of chemicals into the seas, may have provided nutrients to that variety of life forms.
“There are ideas of creating links between the geotectonic world, on the one hand, and biology, on the other.
The work of specialists in earth sciences in this context, "said Goodge," must restore the general picture of the world at that distant time. "
Source: National Science Foundation
Translation of the article is made for the site magov.net
Source: https://habr.com/ru/post/31649/
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