Possible large Pleistocene Epoch impact crater found in Greenland

[rogue06]

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

[mossrose]

[rogue06]

Upset that I didn't ask if you saw it?

[mossrose]

Upset that I didn't ask if you saw it?

Waiting for you to blame me for it.

[rogue06]

Waiting for you to blame me for it.

[shunyadragon]

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.

[mossrose]

CraterLakeAerial.jpg



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

[rogue06]

It would also be the only one known in Greenland

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

[oxmixmudd]

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

[rogue06]

Any references?

Click on the provided hyperlink. It goes to the Abstract.

[oxmixmudd]

Click on the provided hyperlink. It goes to the Abstract.

Oh - sorry! I didn't notice that was a hyperlink, no idea why. Thanks.

Jim