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Kaali Lake, Estonia

Between 7500 and 2500 years ago, a space object composed of coarse octahedrite fell into Earth’s gravity well and broke into huge flaming pieces.  Although much of the object’s mass and velocity were lost passing through the atmosphere, a number of large pieces (with a total mass estimated to be about eighty tons) struck the Saareemaa island in what is now northern Estonia.  Since these fragments were traveling between 10 and 20 kilometers per second, a substantial amount of kinetic energy was released: the impact probably had approximately the same energy yield as the Hiroshima atomic bomb.  The area was inhabited by Bronze Age humans and those who were not incinerated must have been appalled when a ball of incandescent hellfire swallowed a whole forest with deafening thunder.

The impact formed the Kaali crater field.  Since the impact occurred so recently, the craters are still quite pronounced.  The largest crater has a diameter of 110 meters (330 feet) and contains a freshwater lake at its bottom.  The smallest crater (which I unfortunately could not find a picture of) is only about 10 meters across and a meter deep.

PAnoramic shot of Kaali Lake

As at Lake Lonar and the Great Serpeant Mound Crater, there is sacred architecture affiliated with the Kaali Crater field.  During the Iron Age, unknown masons constructed a 470 meter long stone wall around the lake. Since the body of water is nearly a perfect circle it looks deceptively small but, aas you can see in the picture at the top, the lake is actually large and deep. Kaali Lake has been a sacred lake for a long time and local reverence suggests that it still is. Additionally, numerous domestic animal remains from the area around the lake indicate that the area has been a sacrificial ground for thousands of years.  In fact some animal sacrifices date as recently as the 17th century—it seems that Estonia’s conversion to Christianity did not preclude some surviving pagan traditions.  Certain stories from Finnish mythology seem to relate to the lake: one tale relates how a trickster god stole the sun.  The virgin goddess of the air, trying to make manufacture a second sun let a flaming spark fall down—it drifted  into the forested islands south of  Finland and caused a great fire which humankind saved and used for heating, cooking,  and forging.

In the impact crater of a giant meteor, an unknown ancient race built the largest snake effigy on the planet… Is this the beginning of a lurid sci-fi fantasy novel? No, it’s the description of an actual place.  This haunting structure which was built for unknown reasons by a mystery race can be found in deepest…um…Ohio!

The Great Serpent Mound is an ancient earthwork located in Adams County, Ohio.  Shaped like a snake devouring an egg, the mound is 410 meters (1,330 feet long) and a meter tall (3 feet).  The undulating form of the snake has been tied to astronomical phenomena but it is unclear why it was built or what purposes (if any) it served. It reminds me somewhat of the Rainbow Serpent, Wadjet, Nüwa, and other snake deities, but since there is no historical or ethnological record of its purpose, such connections are only airy speculation.

Possible Astronomical Significance of the Great Serpent Mound

An even greater mystery of the structure is who built it. Over the years scholars and archaeologists have variously posited that it was created by the Adena culture (1000 to 200 BC), or by tribes from the Hopewell tradition (200 BC to 500 AD), or by the Fort Ancient culture (1000 AD-1750 AD).  Of course the mound was known long before its “discovery” by European settlers. Unfortunately, the Native Americans of the region seemed just as confused about its provenance as anyone. For what it is worth, Native Americans of the Lenni Lenape (later Delaware) nation told missionaries that the mound was built by the Allegheny or Allegewi People, (who were also sometimes called the Tallegewi), a possibly mythical progenitor race who lived in the Ohio Valley in ancient times before 1200 BC.

The Great Serpent Mound from the Air

It is obvious that a date is thoroughly confused when it varies by as much as 3,000 years! Fortunately there are a few pieces of actual evidence associated with the mound. Adena graves were found and excavated near the Serpent Mound (Adena people were culturally and physically distinct from other peoples of the Ohio valley). Other Adena sites have revealed that these peoples built elaborate circular and winding earthworks and had a fascination with astronomical phenomena. The few pieces of Aedena art even seem to bear an aesthetic connection.

A Serpent Carved from Micah by the Adena or Hopewell

Frustratingly, carbon dating of charcoal taken from within the mound seems to indicate that it was built (or at least refurbished) long after the Adena culture declined and vanished. Conducted in the nineteen nineties, these tests indicated that parts (or all) of the Serpent Mound was built around 1070 AD.  The mound would thus have been made by people of the Fort Ancient Culture–but the Fort Ancient people do not seem to have evinced the same artistic and cosmological sensibilities as are reflected in the mound.  Additionally the mound was uncharacteristic of Fort Ancient culture in its lack of buried valuables.

A painting of Fort Ancient Civilization

Charcoal fragments are easily displaced by bioturbation and burrowing animals, so the carbon dating stands in question. The Fort Ancient people are known to have had contact with the intense pyramid building, city-dwelling (serpent worshipping) Mississippian cultures which were flourishing from Illinois down to the Gulf of Mexico. Perhaps outside cultural influences lead to the mound’s construction. Furthermore the Fort Ancient people got their name from the fact that they lived on huge earthworks built by the vanished Hopewell people (who are also potential builders of the Great Serpent Mound). Perhaps the Fort Ancient tribes also renovated and re-purposed the Great Serpent Mound from older Adena or Hopewell builders.  We simply are not certain about who crafted the Great Serpent Mound–but it is to be hoped that further evidence will clarify the issue.

By now space enthusiast readers are probably chaffing at all of this human history: in the first paragraph I mentioned that the Great Serpent Mound is located in a meteor impact crater. relates how the crater was discovered by scholars studying the Great Serpent Mound:

After the mound was discovered it was noticed that the geology of the surrounding area differed greatly from that found elsewhere in Ohio. John Locke, who explored the area in the 1830’s noted that “a region of no small extent had sunk down several hundred feet, producing faults, dislocations and upturnings of the layers of the rocks.” At the time he thought the he had discovered a “sunken mountain.” Some of the areas look like they have slid straight down while others have risen almost 1,000 feet straight up. Over time more evidence has been found. Eventually in the 1970’s, core samples were taken from the crater area. Scientists have found iridium at levels up to 10 times that normally found in the Earth’s crust, soot from what may be scorched limestone, deformed grains of sand, and quartz with microscopic fractures. In addition “shatter cones” have been found from the surface down similar to those found in Nevada at nuclear weapon test sites.  

Such features are the smoking gun evidence of meteor strikes and scientists have since concluded that the crater is about 250 million years old (which was approximately the same era the Paleozoic came to an end). Over a quarter of a billion years the crater has deformed greatly, to such an extent that it is not immediately recognizable (unlike more contemporary strike sites such as Lake Lonar).

The Eocene (Illustration by Bob Hynes for the Smithsonian Institution)

The Eocene epoch (which lasted from 56 million ago to 34 million years ago) was hot!  Temperate forests ran all the way to the poles.  Steamy tropical jungles grew in the latitude where Maine is now and the equatorial regions of earth were (probably) sweltering. Tropical reefs formed in the coastal waters around a heavily forested and ice-free Antarctica. Since there was not year-round ice at each pole, the sea levels were much higher.

A Global Map of the Early Eocene (map by Dr. Ron Blakey)

The Eocene was a time when most of the contemporary mammalian orders first appeared.  The earliest artiodactyls, perissodactyls, rodents, bats, probiscideans, sirenians, and primates all originated during this time.  Of course mammals were not the only story: the Eocene was also a time of great diversification for birds and many familiar orders of avians developed then.  Reptiles begin to put the setbacks which marked the end of the Cretaceous behind them and several giant new species emerged including an immense tropical ur-python and a host of crocodiles and turtles. It is harrowing to think that the first wee dawn horses and cute little early atiodactyls were forced to contend with a 13 meter long super snakes and giant crocodilians (which flourished in the great hot swamps of Alaska), but such is the case.

Titanboa with Ancient Crocodilian (painting by Jason Bourque)

The high temperatures of the Eocene are perplexing to scientists.  By contrast, the temperatures of the Paleocene (which was the first era of the Cenezoic and had directly preceded the Eocene) were much more temperate. In fact the temperature spike of 56 million years ago seems to have ended the Paleocene and brought about the diversification of Eocene life.  The rapid warming is known as the Palaeocene-Eocene thermal maximum and scientists have been vigorously debating what caused the climate change.  An immense amount of carbon seems to have entered the atmosphere at this time, which in turn led to greenhouse warming.  It remains controversial as to how such a large quantity of carbon got into the atmosphere.  Comet/meteorite impact, massive peat fires, and volcanic activity have been suggested as triggers, however supporting evidence is lacking.  The release of globally significant quantities of hydrocarbons–which had been trapped in undersea clathrates seems like a more feasible hypothesis, as does the idea that the earth’s orbit brought the planet closer to the sun for a time.

Phenacodus, a goat-sized grazer of the Eocene era (painting by Heinrich Harder)

The end of the Eocene was also linked to the carbon cycle.  Reduced carbon dioxide in the atmosphere seems to have led to global cooling and newly evolved varieties of grasses began to invade large swaths of the world.  Additionally two massive meteor strikes in Siberia and Maryland combined with substantial volcanic activity to finish off the long hot summer. But during the Oligocene, the era which followed the Eocene, the world was a much more familiar place inhabited by orders of animals which are still here with us today (or are us–since primates first evolved during the Eocene).

Ye Olde Ferrebeekeeper Archives

August 2020