Ice Age Asteroid Crater Discovered Beneath Greenland Glacier

It is the first impact crater discovered under one of Earth’s ice
sheets, according to the scientists who found it.

By Nicholas St. Fleur

Nov. 14, 2018

Buried beneath a half mile of snow and ice in Greenland, scientists have uncovered an impact crater large enough to swallow the District of Columbia.

The finding suggests that a giant iron asteroid smashed into what is
today a glacier during the last ice age, an era known as the Pleistocene
Epoch that started 2.6 million years ago. When it ended only 11,700
years ago, mega-fauna like saber-toothed cats had died out while
humanity had inherited the Earth.

The discovery could lead to insights into the ice age climate, and the
effects on it from the eruption of debris that would have resulted from
such a cataclysmic collision.

“This is the first impact crater found beneath one of our planet’s ice sheets,” said Kurt Kjær, a geologist at the Center for GeoGenetics at
the Natural History Museum of Denmark and lead author of the study,
published Wednesday in the journal Science Advances.

In 2015, Dr. Kjær and a colleague were analyzing a NASA map of Greenland
when they noticed an enormous circular depression on the Hiawatha
Glacier at Greenland’s northwest tip.

“There was a hidden landscape starting to take shape,” said Dr. Kjær. “We looked at it and said, ‘What is that?’”

At that moment Dr. Kjær thought about the car-size meteorite on display
in the courtyard near his office in Copenhagen, which had coincidentally
been recovered from the northwest of Greenland. He and his colleague
joked that perhaps the circular structure was a crater left by an asteroid.

After the laughs subsided, they realized their suggestion might not be far-fetched. “There’s only so many ways you could create a circular
feature beneath an ice sheet,” said Dr. Kjær.

For three days in May 2016, his team flew over the crater in a German
airplane with ice-penetrating radar, drawing imaginary grid lines across
the surface.

John Paden, a radio-glaciologist at the University of Kansas, operated
the radar on the flight. Every second it sent 12,000 radio wave pulses
down into the ice, reflecting off the ice layers and allowing the team
to measure the thickness, structure and age of the ice sheet.

The aerial survey confirmed that there was a huge pit with an elevated, circular rim and uplifting structures in the center, all telltale signs
of an impact crater. The team’s analysis showed that the Hiawatha crater
was nearly 1,000 feet deep and 20 miles in diameter, placing it among
Earth’s 25 largest impact craters, although much smaller than the
90-mile crater left by the dino-busting Chicxulub impact.

“Once you start looking for structures beneath the ice that look like an impact crater, Hiawatha sticks out like a sore thumb,” said Joseph
MacGregor, a glaciologist at NASA Goddard Space Flight Center in
Maryland and a co-author of the study.

The bowl of the crater presses right against the edge of the glacier,
giving the wandering ice sheet a semi-circle-like appearance that is
visible from above. Breaking out from that semicircle is a white tongue
of ice, a large river containing sediments from the bottom of the ice sheet.

Dr. Kjær ventured to the floodplain via helicopter and collected
sediment. He found what he said were pieces of highly shocked quartz,
which signaled that a violent impact had occurred at some time in the
area’s history. The area’s sediments also had high concentrations of nickel, cobalt, chromium, gold and platinum, an indicator that the
meteorite was made of iron.

Because the team has not yet searched for ejected material from the
impact in ice cores, they cannot establish an accurate date for the
impact, beyond saying it occurred during the Pleistocene. Their next
steps are to determine whether the asteroid smashed into a glacier or an
area that was subsequently covered by ice, and to assess the climatic
effects of the impact.

Dr. Kjær still wonders if the meteorite in the courtyard outside his
office, which was found about 200 miles away from the Hiawatha crater,
may hold clues to better understanding the ancient impact.

“Even though we have looked into the planet’s surface so much, with
every type of equipment,” said Dr. Kjær, “the Age of Discovery is not
over yet.”

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Saturday, November 17, 2018 at 5:36:16 AM UTC+2, Travis McGee wrote:

Ice Age Asteroid Crater Discovered Beneath Greenland Glacier

It is the first impact crater discovered under one of Earth’s ice
sheets, according to the scientists who found it.

By Nicholas St. Fleur

Nov. 14, 2018

Buried beneath a half mile of snow and ice in Greenland, scientists have uncovered an impact crater large enough to swallow the District of Columbia.

The finding suggests that a giant iron asteroid smashed into what is
today a glacier during the last ice age, an era known as the Pleistocene Epoch that started 2.6 million years ago. When it ended only 11,700
years ago, mega-fauna like saber-toothed cats had died out while
humanity had inherited the Earth.

The discovery could lead to insights into the ice age climate, and the effects on it from the eruption of debris that would have resulted from
such a cataclysmic collision.

“This is the first impact crater found beneath one of our planet’s ice sheets,” said Kurt Kjær, a geologist at the Center for GeoGenetics at
the Natural History Museum of Denmark and lead author of the study, published Wednesday in the journal Science Advances.

In 2015, Dr. Kjær and a colleague were analyzing a NASA map of Greenland when they noticed an enormous circular depression on the Hiawatha
Glacier at Greenland’s northwest tip.

“There was a hidden landscape starting to take shape,” said Dr. Kjær. “We looked at it and said, ‘What is that?’”

At that moment Dr. Kjær thought about the car-size meteorite on display
in the courtyard near his office in Copenhagen, which had coincidentally been recovered from the northwest of Greenland. He and his colleague
joked that perhaps the circular structure was a crater left by an asteroid.

After the laughs subsided, they realized their suggestion might not be far-fetched. “There’s only so many ways you could create a circular feature beneath an ice sheet,” said Dr. Kjær.

For three days in May 2016, his team flew over the crater in a German airplane with ice-penetrating radar, drawing imaginary grid lines across
the surface.

John Paden, a radio-glaciologist at the University of Kansas, operated
the radar on the flight. Every second it sent 12,000 radio wave pulses
down into the ice, reflecting off the ice layers and allowing the team
to measure the thickness, structure and age of the ice sheet.

The aerial survey confirmed that there was a huge pit with an elevated, circular rim and uplifting structures in the center, all telltale signs
of an impact crater. The team’s analysis showed that the Hiawatha crater was nearly 1,000 feet deep and 20 miles in diameter, placing it among Earth’s 25 largest impact craters, although much smaller than the
90-mile crater left by the dino-busting Chicxulub impact.

“Once you start looking for structures beneath the ice that look like an impact crater, Hiawatha sticks out like a sore thumb,” said Joseph MacGregor, a glaciologist at NASA Goddard Space Flight Center in
Maryland and a co-author of the study.

The bowl of the crater presses right against the edge of the glacier,
giving the wandering ice sheet a semi-circle-like appearance that is
visible from above. Breaking out from that semicircle is a white tongue
of ice, a large river containing sediments from the bottom of the ice sheet.

Dr. Kjær ventured to the floodplain via helicopter and collected
sediment. He found what he said were pieces of highly shocked quartz,
which signaled that a violent impact had occurred at some time in the area’s history. The area’s sediments also had high concentrations of nickel, cobalt, chromium, gold and platinum, an indicator that the
meteorite was made of iron.

Because the team has not yet searched for ejected material from the
impact in ice cores, they cannot establish an accurate date for the
impact, beyond saying it occurred during the Pleistocene. Their next
steps are to determine whether the asteroid smashed into a glacier or an area that was subsequently covered by ice, and to assess the climatic effects of the impact.

Dr. Kjær still wonders if the meteorite in the courtyard outside his office, which was found about 200 miles away from the Hiawatha crater,
may hold clues to better understanding the ancient impact.

“Even though we have looked into the planet’s surface so much, with every type of equipment,” said Dr. Kjær, “the Age of Discovery is not over yet.”

I read from some publication that estimated size of this asteroid
could have been about 1.2 km of its diameter.

If I remember right, Schumacher-Levy pearl comet hit Jupiter with about
10 - 20 pieces of size 1 - 2 km 20-30 years ago.
This phenomena was photographed by astronomers.

Explosion marks on the Jupiter was about size of the Earth's diameter.

Asteroid which caused 32 km (about 20 miles) diameter crater on the
Hiawatha Glacier could have caused also about Earth's diameter
size explosion ?

Hannu

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

WebGoogle+GmailWebmore ▼
↰ sci.geo.geology
Ice Age Asteroid Crater Discovered Beneath Greenland Glacier 11/16/18Travis McGee
Ice Age Asteroid Crater Discovered Beneath Greenland Glacier

It is the first impact crater discovered under one of Earth’s ice
sheets, according to the scientists who found it.

By Nicholas St. Fleur

Nov. 14, 2018

Buried beneath a half mile of snow and ice in Greenland, scientists have uncovered an impact crater large enough to swallow the District of Columbia.

The finding suggests that a giant iron asteroid smashed into what is
today a glacier during the last ice age, an era known as the Pleistocene
Epoch that started 2.6 million years ago. When it ended only 11,700
years ago, mega-fauna like saber-toothed cats had died out while
humanity had inherited the Earth.

The discovery could lead to insights into the ice age climate, and the
effects on it from the eruption of debris that would have resulted from
such a cataclysmic collision.

“This is the first impact crater found beneath one of our planet’s ice sheets,” said Kurt Kjær, a geologist at the Center for GeoGenetics at
the Natural History Museum of Denmark and lead author of the study,
published Wednesday in the journal Science Advances.

In 2015, Dr. Kjær and a colleague were analyzing a NASA map of Greenland
when they noticed an enormous circular depression on the Hiawatha
Glacier at Greenland’s northwest tip.

“There was a hidden landscape starting to take shape,” said Dr. Kjær. “We looked at it and said, ‘What is that?’”

At that moment Dr. Kjær thought about the car-size meteorite on display
in the courtyard near his office in Copenhagen, which had coincidentally
been recovered from the northwest of Greenland. He and his colleague
joked that perhaps the circular structure was a crater left by an asteroid.

After the laughs subsided, they realized their suggestion might not be far-fetched. “There’s only so many ways you could create a circular feature beneath an ice sheet,” said Dr. Kjær.

For three days in May 2016, his team flew over the crater in a German
airplane with ice-penetrating radar, drawing imaginary grid lines across
the surface.

John Paden, a radio-glaciologist at the University of Kansas, operated
the radar on the flight. Every second it sent 12,000 radio wave pulses
down into the ice, reflecting off the ice layers and allowing the team
to measure the thickness, structure and age of the ice sheet.

The aerial survey confirmed that there was a huge pit with an elevated, circular rim and uplifting structures in the center, all telltale signs
of an impact crater. The team’s analysis showed that the Hiawatha crater
was nearly 1,000 feet deep and 20 miles in diameter, placing it among Earth’s 25 largest impact craters, although much smaller than the
90-mile crater left by the dino-busting Chicxulub impact.

“Once you start looking for structures beneath the ice that look like an impact crater, Hiawatha sticks out like a sore thumb,” said Joseph MacGregor, a glaciologist at NASA Goddard Space Flight Center in
Maryland and a co-author of the study.

The bowl of the crater presses right against the edge of the glacier,
giving the wandering ice sheet a semi-circle-like appearance that is
visible from above. Breaking out from that semicircle is a white tongue
of ice, a large river containing sediments from the bottom of the ice sheet.

Dr. Kjær ventured to the floodplain via helicopter and collected
sediment. He found what he said were pieces of highly shocked quartz,
which signaled that a violent impact had occurred at some time in the
area’s history. The area’s sediments also had high concentrations of nickel, cobalt, chromium, gold and platinum, an indicator that the
meteorite was made of iron.

Because the team has not yet searched for ejected material from the
impact in ice cores, they cannot establish an accurate date for the
impact, beyond saying it occurred during the Pleistocene. Their next
steps are to determine whether the asteroid smashed into a glacier or an
area that was subsequently covered by ice, and to assess the climatic
effects of the impact.

Dr. Kjær still wonders if the meteorite in the courtyard outside his
office, which was found about 200 miles away from the Hiawatha crater,
may hold clues to better understanding the ancient impact.

Humans witnessed fire-covered Earth at end of Ice Age
By Eleanor Imster in EARTH | HUMAN WORLD | February 7, 2018

I seem to recall widespread evidence for fires across North America as well as micro-diamonds in sediment across the Eastern US

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Friday, February 8, 2019 at 11:57:01 PM UTC+2, lbjohn...@yahoo.com wrote:

WebGoogle+GmailWebmore ▼
↰ sci.geo.geology
Ice Age Asteroid Crater Discovered Beneath Greenland Glacier 11/16/18Travis McGee
Ice Age Asteroid Crater Discovered Beneath Greenland Glacier

It is the first impact crater discovered under one of Earth’s ice
sheets, according to the scientists who found it.

By Nicholas St. Fleur

Nov. 14, 2018

Buried beneath a half mile of snow and ice in Greenland, scientists have uncovered an impact crater large enough to swallow the District of Columbia.

The finding suggests that a giant iron asteroid smashed into what is
today a glacier during the last ice age, an era known as the Pleistocene Epoch that started 2.6 million years ago. When it ended only 11,700
years ago, mega-fauna like saber-toothed cats had died out while
humanity had inherited the Earth.

The discovery could lead to insights into the ice age climate, and the effects on it from the eruption of debris that would have resulted from
such a cataclysmic collision.

“This is the first impact crater found beneath one of our planet’s ice sheets,” said Kurt Kjær, a geologist at the Center for GeoGenetics at
the Natural History Museum of Denmark and lead author of the study, published Wednesday in the journal Science Advances.

In 2015, Dr. Kjær and a colleague were analyzing a NASA map of Greenland when they noticed an enormous circular depression on the Hiawatha
Glacier at Greenland’s northwest tip.

“There was a hidden landscape starting to take shape,” said Dr. Kjær. “We looked at it and said, ‘What is that?’”

At that moment Dr. Kjær thought about the car-size meteorite on display
in the courtyard near his office in Copenhagen, which had coincidentally been recovered from the northwest of Greenland. He and his colleague
joked that perhaps the circular structure was a crater left by an asteroid.

After the laughs subsided, they realized their suggestion might not be far-fetched. “There’s only so many ways you could create a circular feature beneath an ice sheet,” said Dr. Kjær.

For three days in May 2016, his team flew over the crater in a German airplane with ice-penetrating radar, drawing imaginary grid lines across
the surface.

John Paden, a radio-glaciologist at the University of Kansas, operated
the radar on the flight. Every second it sent 12,000 radio wave pulses
down into the ice, reflecting off the ice layers and allowing the team
to measure the thickness, structure and age of the ice sheet.

The aerial survey confirmed that there was a huge pit with an elevated, circular rim and uplifting structures in the center, all telltale signs
of an impact crater. The team’s analysis showed that the Hiawatha crater was nearly 1,000 feet deep and 20 miles in diameter, placing it among Earth’s 25 largest impact craters, although much smaller than the
90-mile crater left by the dino-busting Chicxulub impact.

“Once you start looking for structures beneath the ice that look like an impact crater, Hiawatha sticks out like a sore thumb,” said Joseph MacGregor, a glaciologist at NASA Goddard Space Flight Center in
Maryland and a co-author of the study.

The bowl of the crater presses right against the edge of the glacier,
giving the wandering ice sheet a semi-circle-like appearance that is
visible from above. Breaking out from that semicircle is a white tongue
of ice, a large river containing sediments from the bottom of the ice sheet.

Dr. Kjær ventured to the floodplain via helicopter and collected
sediment. He found what he said were pieces of highly shocked quartz,
which signaled that a violent impact had occurred at some time in the area’s history. The area’s sediments also had high concentrations of nickel, cobalt, chromium, gold and platinum, an indicator that the
meteorite was made of iron.

Because the team has not yet searched for ejected material from the
impact in ice cores, they cannot establish an accurate date for the
impact, beyond saying it occurred during the Pleistocene. Their next
steps are to determine whether the asteroid smashed into a glacier or an area that was subsequently covered by ice, and to assess the climatic effects of the impact.

Dr. Kjær still wonders if the meteorite in the courtyard outside his office, which was found about 200 miles away from the Hiawatha crater,
may hold clues to better understanding the ancient impact.

Humans witnessed fire-covered Earth at end of Ice Age
By Eleanor Imster in EARTH | HUMAN WORLD | February 7, 2018

I seem to recall widespread evidence for fires across North America as well as
micro-diamonds in sediment across the Eastern US

Two references found from this were:

Wolbach Wendy S. et al 2018.
Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact about 12800 Years Ago.
1. Ice Cores and Glaciers.
Journal of Geology, vol. 126, Mar 2018, Issue 2, p. 165-184. 20 p, 1 Chart, 3 Graphs, 1 Map. (in appendixes on line).

Wolbach Wendy S. et al 2018.
Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact about 12800 Years Ago.
2. Lake, Marine, and Terrestrial Sediments.
Journal of Geology, vol. 126, Mar 2018, Issue 2, p 185-205, 21 p, 1 Chart,
8 Graphs, 1 Map. (in appendixes on line).

Best Regards,

Hannu Poropudas

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)