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a cosmic impact that caused destruction of one of the world'searliest human settlements



 
 
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Old March 10th 20, 04:54 PM posted to alt.astronomy
a425couple
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Posts: 216
Default a cosmic impact that caused destruction of one of the world'searliest human settlements

from
https://phys.org/news/2020-03-eviden...CFrHpFhYJQuuLE

Researchers find evidence of a cosmic impact that caused destruction of
one of the world's earliest human settlements
by Sonia Fernandez, University of California - Santa Barbara

Location of Abu Hureyra (adapted from Moore et al.. (a) Map of the
Middle East, showing Abu Hureyra location (AH) in Syria. (b) Map of the
Abu Hureyra tell, showing locations of excavation trenches labeled A-G
near a back channel of Euphrates River that is now abandoned. Sediment
samples from Trenches D, E, and G (blue rectangles) contain abundance
peaks in YDB proxies, including spherules, nanodiamonds, meltglass, and
platinum. Credit: Scientific Reports (2020). DOI: 10.1038/s41598-020-60867-w
Before the Taqba Dam impounded the Euphrates River in northern Syria in
the 1970s, an archaeological site named Abu Hureyra bore witness to the
moment ancient nomadic people first settled down and started cultivating
crops. A large mound marks the settlement, which now lies under Lake Assad.


But before the lake formed, archaeologists were able to carefully
extract and describe much material, including parts of houses, food and
tools—an abundance of evidence that allowed them to identify the
transition to agriculture nearly 12,800 years ago. It was one of the
most significant events in our Earth's cultural and environmental history.

Abu Hureyra, it turns out, has another story to tell. Found among the
cereals and grains and splashed on early building material and animal
bones was meltglass, some features of which suggest it was formed at
extremely high temperatures—far higher than what humans could achieve at
the time—or that could be attributed to fire, lighting or volcanism.

"To help with perspective, such high temperatures would completely melt
an automobile in less than a minute," said James Kennett, a UC Santa
Barbara emeritus professor of geology. Such intensity, he added, could
only have resulted from an extremely violent, high-energy, high-velocity
phenomenon, something on the order of a cosmic impact.

Based on materials collected before the site was flooded, Kennett and
his colleagues contend Abu Hureyra is the first site to document the
direct effects of a fragmented comet on a human settlement. These
fragments are all part of the same comet that likely slammed into Earth
and exploded in the atmosphere at the end of the Pleistocene epoch,
according to Kennett. This impact contributed to the extinction of most
large animals, including mammoths, and American horses and camels; the
disappearance of the North American Clovis culture; and to the abrupt
onset of the end-glacial Younger Dryas cooling episode.

The team's findings are highlighted in a paper published in the Nature
journal Scientific Reports.

"Our new discoveries represent much more powerful evidence for very high
temperatures that could only be associated with a cosmic impact," said
Kennett, who with his colleagues first reported evidence of such an
event in the region in 2012.

Abu Hureyra lies at the easternmost sector of what is known as the
Younger Dryas Boundary (YDB) strewnfield, which encompasses about 30
other sites in the Americas, Europe and parts of the Middle East. These
sites hold evidence of massive burning, including a widespread
carbon-rich "black mat" layer that contains millions of nanodiamonds,
high concentrations of platinum and tiny metallic spherules formed at
very high temperatures. The YDB impact hypothesis has gained more
traction in recent years because of many new discoveries, including a
very young impact crater beneath the Hiawatha Glacier of the Greenland
ice sheet, and high-temperature meltglass and other similar evidence at
an archaeological site in Pilauco, located in southern Chile.



"The Abu Hureyra village would have been abruptly destroyed," Kennett
said. Unlike the evidence from Pilauco, which was limited to human
butchering of large animals up to but not younger than the YDB impact
burn layer, Abu Hureyra shows direct evidence of the disaster on this
early human settlement. An impact or an airburst must have occurred
sufficiently close to send massive heat and molten glass over the entire
early village, Kennett noted.

The glass was analyzed for geochemical composition, shape, structure,
formation temperature, magnetic characteristics and water content.
Results from the analysis showed that it formed at very high
temperatures and included minerals rich in chromium, iron, nickel,
sulfides, titanium and even platinum- and iridium-rich melted iron—all
of which formed in temperatures higher than 2200 degrees Celsius.

"The critical materials are extremely rare under normal temperatures,
but are commonly found during impact events," Kennett said. According to
the study, the meltglass was formed "from the nearly instantaneous
melting and vaporization of regional biomass, soils and floodplain
deposits, followed by instantaneous cooling." Additionally, because the
materials found are consistent with those found in the YDB layers at the
other sites across the world, it's likely that they resulted from a
fragmented comet, as opposed to impacts caused by individual comets or
asteroids.

"A single major asteroid impact would not have caused such widely
scattered materials like those discovered at Abu Hureyra," Kennett said.
"The largest cometary debris clusters are proposed to be capable of
causing thousands of airbursts within a span of minutes across one
entire hemisphere of Earth. The YDB hypothesis proposed this mechanism
to account for the widely dispersed coeval materials across more than
14,000 kilometers of the Northern and Southern Hemispheres. Our Abu
Hureyra discoveries strongly support a major impact event from such a
fragmented comet."

Explore further

--------------------------
Geologic evidence supports theory that major cosmic impact event
occurred approximately 12,800 years ago
--------------------------
More information: Andrew M. T. Moore et al. Evidence of Cosmic Impact at
Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka):
High-temperature melting at 2200 °C, Scientific Reports (2020). DOI:
10.1038/s41598-020-60867-w
Journal information: Scientific Reports
Provided by University of California - Santa Barbara

  #2  
Old March 10th 20, 05:32 PM posted to alt.astronomy
a425couple
external usenet poster
 
Posts: 216
Default a cosmic impact that caused destruction of one of the world'searliest human settlements

On 3/10/2020 8:54 AM, a425couple wrote:
from
https://phys.org/news/2020-03-eviden...CFrHpFhYJQuuLE

Researchers find evidence of a cosmic impact that caused destruction of
one of the world's earliest human settlements
by Sonia Fernandez, University of California - Santa Barbara

Location of Abu Hureyra (adapted from Moore et al.. (a) Map of the
Middle East, showing Abu Hureyra location (AH) in Syria.


(I'm frustrated at the recent releases of theories of
asteroid impacts,,, more specifically that one hit about
13,000 years ago.
Some think it was like here, in Syria.
Others that it was in Greenland.
And others are claiming that it was in southern Chile.
Ohhh Well!

Here is another about the Syrian area.)

from
https://www.foxnews.com/science/gian..._XQW2BnUT_rYuc

Giant asteroid apocalypse 13K years ago was witnessed by ancient humans,
experts believe
By Chris Ciaccia | Fox News

The asteroid that hit Earth nearly 13,000 years ago and ended the
Pleistocene era likely wiped out an ancient civilization in what is
modern-day Syria, according to newly discovered evidence.

The research, published in Scientific Reports, notes that experts
discovered remnants of glass that were created during a high-impact
event, as well as minerals such as chromium, iron, nickel and others,
all of which formed in temperatures higher than 2,200 degrees Celsius,
according to a statement from the University of California-Santa Barbara.

“To help with perspective, such high temperatures would completely melt
an automobile in less than a minute,” said one of the study's co-authors
and UC Santa Barbara emeritus professor of geology James Kennett in the
statement.

(Credit: University of California Santa Barbara)
(Credit: University of California Santa Barbara)

The discovery was made at a site known as Abu Hureyra, which was
abandoned roughly 5,000 years ago.

Known as the Pleistocene Epoch, the most recent ice age is generally
defined as starting 2.6 million years ago and ending approximately
11,700 years ago

The glass is believed to have formed “from the nearly instantaneous
melting and vaporization of regional biomass, soils and floodplain
deposits, followed by instantaneous cooling," according to the study.
Kennett added that the materials found are "extremely rare" under normal
temperatures, but common during impact events.

A "single, major asteroid impact" could not have caused the widely
scattered material discovered at Abu Hureyra and that it was more likely
a fragmented comet, the researcher said.

“The largest cometary debris clusters are proposed to be capable of
causing thousands of airbursts within a span of minutes across one
entire hemisphere of Earth," Kennett explained. "The [Younger Dryas
Boundary] hypothesis proposed this mechanism to account for the widely
dispersed coeval materials across more than 14,000 kilometers [8,700
miles] of the Northern and Southern Hemispheres. Our Abu Hureyra
discoveries strongly support a major impact event from such a fragmented
comet.”

Previous studies have focused on the Younger Dryas event, a period that
saw the extinction of species such as woolly mammoths, bison and giant
sloths, causing global consequences.

In October 2019, a study was published that said a brief ice age period
occurred roughly 12,800 years ago and was caused by an asteroid impact,
after researchers found high levels of iridium and platinum in White
Pond near Elgin, S.C.

An enormous crater, first discovered in 2015 but not officially verified
until November 2018, left a 19-mile crater in Greenland and may have
caused the disappearance of the Clovis people, a mysterious prehistoric
group that vanished without a trace, according to The Sun.

According to NASA, the massive hole is "one of the 25 largest impact
craters on Earth" and is said to have "rocked the Northern Hemisphere."


Follow Chris Ciaccia on Twitter @Chris_Ciaccia
 




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