Greenland Crater under the Hiawatha Glacier


The Greenland Crater under the Hiawatha Glacier.
On November 14, 2018, a paper by Kurt Kjær and 21 co-authors in the journal Science Advances
announced the discovery of a crater in the northern part of Greenland that was buried
under the Hiawatha glacier. The paper received wide coverage in the media because scientists
speculated that the extraterrestrial impact that made the crater could be related to the
extinction event in North America and the onset of the Younger Dryas cooling event 12,900
years ago. The study of the Greenland crater was kept
secret from the time that the existence of the crater was suspected in 2015 until the
publication of the paper in 2018. Announcements of extraterrestrial impacts are vigorously
and acrimoniously contested, so it is not surprising that the scientists decided to
withhold information about their discovery until all aspects could be verified. No news
were leaked from the time that the paper was submitted to the journal until its publication
11 months later. The research team used a twin-propeller DC-3
aircraft equipped with a state-of-the-art ice-penetrating radar owned by the Alfred
Wegener Institute for Polar and Marine Research in Bremerhaven, Germany. Three flights, in
May 2016, added 1600 kilometers of fresh data from dozens of transits across the ice. The
radar revealed an impact crater with a diameter of 31 kilometers beneath Hiawatha Glacier and
five prominent bumps in the crater’s center, indicating a central peak rising about 50
meters high. The bottom of the crater was jagged, which was interpreted as a sign of
a recent impact, since an old crater would have been scoured smooth by the action of
the glacier. The topography of the terrain was based on
airborne radar data obtained by NASA from 1997 to 2014, and from radar data obtained
in May of 2016. In this image, black triangles represent elevated peaks in the rim of the
crater. Dark purple circles in the center represent peaks in the central uplift. The
black circles outside the crater show the location where three sediment samples were
collected. The high compressive forces of an extraterrestrial
impact create Planar Deformation Features in quartz crystals. These deformations can
be seen under a microscope as lines with different orientations using polarized light. Some critics
have pointed out that the shocked quartz was obtained outside the crater, rather than within
the crater. The research team plans to get additional samples, but argues that the crystals
that they tested were brought from within the crater by a meltwater stream. Thus far,
every sample that contained shocked quartz also had elevated concentrations of nickel,
cobalt, chromium, platinum group elements, and gold, which are indicative of a relatively
rare iron meteorite. The diameter of an impact crater is related
to the kinetic energy of the projectile. The formation of a 31-km-wide impact crater in
crystalline target rock requires approximately 3×10^21 Joules of energy. Assuming that the
Hiawatha impactor was iron with a density of 8000 kg per cubic meter and its impact
velocity was 20 km per second, the required impactor diameter was about 1.5 kilometers.
The researchers assumed that the impactor was an iron meteorite because iron meteorites
were previously found in Greenland, although the exact composition of the meteorite that
made the crater is not known. Ground-penetrating radar made it possible
to get a view of the crater without the glacier ice. As an additional bonus, the radar images
contained bright reflections at the boundaries of grit from ancient volcanic eruptions. The
research team matched those bright layers to the same layers of grit in ice cores from
other parts of Greenland. This technique revealed that most ice in the Hiawatha crater is perfectly
layered through the past 11,700 years. But in the older, disturbed ice below, the uniform
bright reflections disappear. The deep jumbled layers were dated to 12,800 years ago, which
makes it possible to conclude that the Hiawatha impact crater was formed at or before the
Younger Dryas. Some experts doubt that the impact occurred
as recently as 13,000 years ago because, statistically, impacts the size of the Hiawatha crater occur
only every few million years. Professor Jay Melosh from Purdue said to the Science journal
“This is a hot potato. You’re aware you’re going to set off a firestorm?” Paleoclimatologist
Jennifer Marlon from Yale University said that the Greenland crater is “too small and
too far away to kill off the Pleistocene mammals in the continental United States,” and that
she “can’t imagine how something like this impact in this location could have caused
massive fires in North America.” Soon after the Greenland Crater was announced,
many researchers drew a line between the Greenland Crater and Saginaw Bay, which has been proposed
as the impact point for a meteorite that hit the Laurentide Ice Sheet ejecting ice boulders
that killed the megafauna and created the Carolina Bays. The distance between the Greenland
Crater and Saginaw Bay is 4000 kilometers. Notice that the Nastapoka Arc on the east
side of Hudson Bay is along the line. With the Earth tilted at about 23.4 degrees from
the ecliptic, the line from the Greenland Crater and Saginaw Bay is inclined about 60
degrees from the ecliptic plane.  Future research will be necessary to determine whether
there are any comets or meteor showers with that inclination. If the Greenland and Saginaw
Bay impacts are related, they would have occurred within 7 minutes of each other.   The Earth’s
orbital speed is 30 km/s and its diameter is 12,742 km, so the comet debris would have
had to be in a fairly tight cluster, otherwise multiple impacts would not have occurred due
to the Earth’s speed. The Nastapoka Arc is a prominent, near-perfect
circular arc, covering more than 160° of a 450-km-diameter circle on the east side
of Hudson Bay. The arc is very suggestive of an impact crater and the islands in the
center of the arc seem like the remnants of a central uplift of an impact. The Nastapoka
Arc has been studied previously as a possible impact site, but the results were negative. The idea that the Nastapoka Arc is related to the Younger Dryas event has a long history.
In 2009, Richard Firestone suggested that an impact or extraterrestrial explosion in
the Great Lakes or Hudson Bay could have been responsible for the formation of the Carolina
Bays and the Nebraska Rainwater Basins. The Younger Dryas was followed by meltwater
pulse 1B, from 11,500 to 11,000 years ago. Sea level increased by as much as 28 meters.
The single extraterrestrial impact in Saginaw Bay that created the Carolina Bays was not
sufficient to account for Meltwater Pulse 1B.  If the Greenland crater is confirmed
to have formed at the onset of the Younger Dryas, perhaps the two impacts, plus others
that have not been found yet, could account for the 28 meter sea level rise for Meltwater Pulse 1B. This is an exciting time. This is a time of vindication for all those luminary
thinkers who have been arguing for the existence of advanced antediluvian civilizations and
for the sinking of Atlantis as a historical event, rather than just as a fictional legend.

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