Megafauna Extinctions

About 13,000 years ago, close to 80% of the megafauna were wiped off the map.  Mammoths, mastodons, dire wolves, giant sloths, and smiledons or sabre-tooth tigers all disappeared.  And Clovis points made by Paleo-Indians cannot be found in dig sites after 13,000.  What caused this mass extinction?

About 13,000 years ago, a climate change occurred, called the Younger Dryas, also known as the Big Freeze.  The weather got colder and dryer for over 1,000 years.  Typically, the megafauna had survived many climate changes over the years, so why was this change so devastating?  Well, it seemed to be rather sudden with temperatures dropping about ten degrees and large dust storms and draught killing off plant life.  What caused the Younger Dryas?

There are two major theories as to what caused the Younger Drysas stadial.  First, scientists argue that the earlier warming period caused a significant influx of freshwater along the St. Lawrence River to the North Atlantic that disrupted the current and conveyor system that moderated the weather.  This could have led to colder weather.  Second, some scientists have discovered nano diamonds and other extraterrestrial evidence in the layers above 13,000 years ago.  They have uncovered fullerenes, extraterrestrial carbon carriers, which were also discovered in the Permian-Triassic layer, which could be evidence of a meteorite or comet that caused that extinction as well as that in the Younger Dryas.  Actually, the second theory could be the primary reason with the influx of freshwater being a secondary reason.

The Wisconsin Glacial Episode technically ended about 11,000 years ago, about the same time that the Younger Dryas ended.  The megafauna had survived significant climate variations during the different ice ages over the centuries, so why did the Younger Dryas lead to extinctions?  The first theory does not provide a good answer, but the second one does.  The megafauna could not survive the rapid changes caused by the comet or meteorite that may have hit.  Where is the evidence of a crater in North America?  Well, since it probably struck the deep ice sheets that covered the northern part of North America, the crater in the ice would have melted.

No Clovis points have been found during the Younger Dryas period.  Folsom points dating back to 9,500 years ago were the next spear heads located in America after the Clovis points.  The 3,000 year gap is difficult to bridge.   The Folsom Paleo-Indians seem to have genetic connections to Asia and the Clovis Paleo-Indians may have a nexus to Europe.  If this is true, the Asian presence either was able to survive the Younger Dryas period or entered North America when the climate improved.  They clearly were the forefathers of the Native Americans that populated North America when the European explorers landed on the east coast.

If you examine the moon, there are hundreds of craters, so it would not be unusual for earth to be the target for numerous comets and meteorites over the years.  Most of these craters have been erased by erosion.  If the meteors were large enough, they could have had a devastating impact on life on earth at that time.

One of these was probably the culprit that caused the extinction of the dinosaurs.  At the Cretaceous-Tertiary (K-T) boundary, when the dinosaurs went extinct, there are large amounts of the metal iridium, which typically is not found on earth, but is found on meteorites.  It is highly likely that a large comet or meteorite impacted earth about 13,000 years ago, causing the extinction of the megafauna.