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Thread: Possible large Pleistocene Epoch impact crater found in Greenland

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    Evolution is God's ID rogue06's Avatar
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    Possible large Pleistocene Epoch impact crater found in Greenland

    What appears to be an impact crater measuring approximately 31 km (19¼ mi.) across has been found buried under up to a kilometer of ice beneath Hiawatha Glacier in northwest Greenland by researchers using high-powered ice-penetrating radar and lasers. If confirmed this relatively recent impact crater which is wider than Washington D.C. or Paris, France would rank among the top 25 largest known craters in the world. It would also be the only one known in Greenland.

    The circular formation possesses a clearly defined rim all the way around its circumference that is around 320 meters (1050') above the floor of the crater along with an uplifted area 50 to 70 meters (164 to 230') high in the center of the crater which Kurt Kjær, a geologist at the Natural History Museum of Denmark at the University of Copenhagen and lead author of the study that examined the formation, said is an expected feature and the result of the force of the strike.

    And while the ice prevents direct examination of the site, sediment from it carried by meltwater appears to contain bits of shocked quartz which is typically associated with impact sites. Some of the grains also showed a brown color known as "toasting", which is also a sign of intense energy release. Chemical analysis of the samples revealed traces of rhodium, platinum and palladium all of which are rare in earth rocks.

    Finally, a large fragment of iron meteorite at the University of Copenhagen was originally found some 300 km (186 mi.) from the possible crater.

    The researchers estimate that, based on the size of the crater, the asteroid was likely some 1.2 km (0.75 mi.) across and would have weighed between 11 and 12 billion tons as it entered the atmosphere. And while it isn't possible to date the crater directly Kjær says that its condition strongly indicates that it formed after ice began to cover Greenland, meaning it is less than than 3 myo.

    Still more research is needed to confirm these initial findings.


    Here is the abstract which was published in the open access journal Science Advances:

    Source: A large impact crater beneath Hiawatha Glacier in northwest Greenland


    We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.

    © Copyright Original Source





    Further Reading:

    A large impact crater beneath Hiawatha Glacier in northwest Greenland Full Paper

    Scientists Spot What May Be a Giant Impact Crater Hidden Under Greenland Ice

    City-size impact crater found under Greenland ice

    Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland

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    Quote Originally Posted by mossrose View Post
    Upset that I didn't ask if you saw it?

    I'm always still in trouble again

    "You're by far the worst poster on TWeb" and "TWeb's biggest liar" -- starlight (the guy who says Stalin was a right-winger)

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    Quote Originally Posted by rogue06 View Post
    Upset that I didn't ask if you saw it?
    Waiting for you to blame me for it.



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    Evolution is God's ID rogue06's Avatar
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    Quote Originally Posted by mossrose View Post
    Waiting for you to blame me for it.

    A PIN™ strike hasn't been completely ruled out.

    I'm always still in trouble again

    "You're by far the worst poster on TWeb" and "TWeb's biggest liar" -- starlight (the guy who says Stalin was a right-winger)

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    Quote Originally Posted by rogue06 View Post
    What appears to be an impact crater measuring approximately 31 km (19¼ mi.) across has been found buried under up to a kilometer of ice beneath Hiawatha Glacier in northwest Greenland by researchers using high-powered ice-penetrating radar and lasers. If confirmed this relatively recent impact crater which is wider than Washington D.C. or Paris, France would rank among the top 25 largest known craters in the world. It would also be the only one known in Greenland.

    The circular formation possesses a clearly defined rim all the way around its circumference that is around 320 meters (1050') above the floor of the crater along with an uplifted area 50 to 70 meters (164 to 230') high in the center of the crater which Kurt Kjær, a geologist at the Natural History Museum of Denmark at the University of Copenhagen and lead author of the study that examined the formation, said is an expected feature and the result of the force of the strike.

    And while the ice prevents direct examination of the site, sediment from it carried by meltwater appears to contain bits of shocked quartz which is typically associated with impact sites. Some of the grains also showed a brown color known as "toasting", which is also a sign of intense energy release. Chemical analysis of the samples revealed traces of rhodium, platinum and palladium all of which are rare in earth rocks.

    Finally, a large fragment of iron meteorite at the University of Copenhagen was originally found some 300 km (186 mi.) from the possible crater.

    The researchers estimate that, based on the size of the crater, the asteroid was likely some 1.2 km (0.75 mi.) across and would have weighed between 11 and 12 billion tons as it entered the atmosphere. And while it isn't possible to date the crater directly Kjær says that its condition strongly indicates that it formed after ice began to cover Greenland, meaning it is less than than 3 myo.

    Still more research is needed to confirm these initial findings.


    Here is the abstract which was published in the open access journal Science Advances:

    Source: A large impact crater beneath Hiawatha Glacier in northwest Greenland


    We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.

    © Copyright Original Source





    Further Reading:

    A large impact crater beneath Hiawatha Glacier in northwest Greenland Full Paper

    Scientists Spot What May Be a Giant Impact Crater Hidden Under Greenland Ice

    City-size impact crater found under Greenland ice

    Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
    Currious when the accurately date the time of the impact.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

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    Oops....... mossrose's Avatar
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    Quote Originally Posted by rogue06 View Post
    A PIN™ strike hasn't been completely ruled out.

    CraterLakeAerial.jpg



    I'll go away now and let you guys discuss the topic of the op.


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  8. #8
    Evolution is God's ID rogue06's Avatar
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    Quote Originally Posted by rogue06 View Post
    What appears to be an impact crater measuring approximately 31 km (19¼ mi.) across has been found buried under up to a kilometer of ice beneath Hiawatha Glacier in northwest Greenland by researchers using high-powered ice-penetrating radar and lasers. If confirmed this relatively recent impact crater which is wider than Washington D.C. or Paris, France would rank among the top 25 largest known craters in the world. It would also be the only one known in Greenland.

    The circular formation possesses a clearly defined rim all the way around its circumference that is around 320 meters (1050') above the floor of the crater along with an uplifted area 50 to 70 meters (164 to 230') high in the center of the crater which Kurt Kjær, a geologist at the Natural History Museum of Denmark at the University of Copenhagen and lead author of the study that examined the formation, said is an expected feature and the result of the force of the strike.

    And while the ice prevents direct examination of the site, sediment from it carried by meltwater appears to contain bits of shocked quartz which is typically associated with impact sites. Some of the grains also showed a brown color known as "toasting", which is also a sign of intense energy release. Chemical analysis of the samples revealed traces of rhodium, platinum and palladium all of which are rare in earth rocks.

    Finally, a large fragment of iron meteorite at the University of Copenhagen was originally found some 300 km (186 mi.) from the possible crater.

    The researchers estimate that, based on the size of the crater, the asteroid was likely some 1.2 km (0.75 mi.) across and would have weighed between 11 and 12 billion tons as it entered the atmosphere. And while it isn't possible to date the crater directly Kjær says that its condition strongly indicates that it formed after ice began to cover Greenland, meaning it is less than than 3 myo.

    Still more research is needed to confirm these initial findings.


    Here is the abstract which was published in the open access journal Science Advances:

    Source: A large impact crater beneath Hiawatha Glacier in northwest Greenland


    We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.

    © Copyright Original Source





    Further Reading:

    A large impact crater beneath Hiawatha Glacier in northwest Greenland Full Paper

    Scientists Spot What May Be a Giant Impact Crater Hidden Under Greenland Ice

    City-size impact crater found under Greenland ice

    Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
    It appears that there might be another possibly even much larger crater (100km or 61 mi.) and much older crater (roughly 3 byo) located southeast of the town of Maniitsoq in western Greenland known as the Maniitsoq structure in western Greenland

    I'm always still in trouble again

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    tWebber
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    Quote Originally Posted by rogue06 View Post
    It appears that there might be another possibly even much larger crater (100km or 61 mi.) and much older crater (roughly 3 byo) located southeast of the town of Maniitsoq in western Greenland known as the Maniitsoq structure in western Greenland
    Any references?

    Although the possibility of a more recent crater is of more interest. It seems like the ice flow evidence points to something on the more recent side of the Pleistocene. I am curious if it could be an explanation for the Younger Dryas cooling (~14,500 years ago)


    JIm

    ETA: yes - that is already being floated:

    http://www.sciencemag.org/news/2018/...ct-time-humans
    Jorge's trueorigins paper: "...it is known that other volcanic features match what is usually associated with impact craters including ... shatter cones and crystal deformations"

    Planetary Science Institute: "Shatter cones … are found in only two places on Earth, 1) in nuclear test sites and 2) meteorite impact structures. They are formed as a result of the high pressure, high velocity shock wave ...

    maximum pressures from 45 to 200 times greater than found in volcanic events (2->20 Gpa)

  10. #10
    Evolution is God's ID rogue06's Avatar
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    Quote Originally Posted by oxmixmudd View Post
    Any references?
    Click on the provided hyperlink. It goes to the Abstract.

    I'm always still in trouble again

    "You're by far the worst poster on TWeb" and "TWeb's biggest liar" -- starlight (the guy who says Stalin was a right-winger)

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