3. The Galactic Superwave Explanation of the Megafaunal Extinction and Related Effects

    The superwave theory does not propose a cometary impact or an aerial explosion of one or more cometary bodies as the sole cause of the conflagration/flood demise of the megafauna.  It suggests a scenario that is a bit more complex.  It proposes that lethality was due to a number of factors which arose through the following chain of events:

1) First, there was the arrival of an intense volley of Galactic cosmic rays termed a "Galactic superwave" which lasted several thousand years.  These cosmic rays became magnetically trapped and concentrated in the heliopause sheath and in the bow shock that formed around the heliopause.

2) This solar system "radiation belt" then vaporized comets and frozen cometary debris present within and immediately around the solar system creating a nebula.  Cometary heating in this radiation belt also induced cometary fragmentation and increased the influx of comets into the solar system and hence increasing the chance of terrestrial impacts.

3) Propagating cosmic-ray-driven shock fronts pushed nebular material into the inner solar system substantially increasing the opacity of the zodiacal cloud.

4) This increased solar system nebular congestion, in turn, increased the influx of debris falling onto the Sun and the amount of radiation back-scattered onto the Sun's surface thereby creating an aggravated solar state similar to that seen in T Tauri stars.

5) Solar flare activity jumped by several orders of magnitude destroying the Earth's ozone layer and increasing the influx of harmful UV rays.

6) The entry of cometary and interstellar dust into the solar system and falling onto the Sun would have caused a climatic warming effect on the Earth by increasing the Sun's bolometric luminosity, shifting the solar spectrum toward the infrared which reduced the Earth's albedo, allowing UV radiation to pass through the atmosphere, and by back-scattering outgoing solar radiation back toward the Earth.

7) Giant solar proton events (SPE) produced by the arrival of coronal mass ejections expelled by these super-sized solar flares would have continually impacted the Earth. One that was hundreds of times more energetic than the most intense SPE experienced in modern times would have been sufficiently strong to overpower the geomagnetic field sheath and make contact with the Earth's surface, thereby creating a ground-level firestorm (LaViolette, 1983a, ch. 4; LaViolette, 1997); see posting at http://starburstfound.org/downloads/superwave/Ch-4.pdf . This would explain the occurrence of the black layer found at the Allerod/Younger Dryas boundary.

8) The increased insolation that prevailed during the deglacial period, globally warming the climate to interglacial temperatures, would have at times rapidly melted the upper surface of the ice sheets.  This would have caused high altitude water ponding and dam failures that would have released immense meltwater deluges.  These "glacier waves" would have magnified in intensity as they swept toward the ice sheet margin, continuing on at high speed across the continental land mass to bury unsuspecting megafauna.  These would have been particularly severe at the time of a ground contacting CME such as is proposed to have struck the Earth close to the time of the Younger Dryas megafaunal termination boundary.

9) The elevated flux of solar cosmic rays striking the Earth's atmosphere would have generated condensation nuclei which would have formed high altitude clouds.  These, in turn, would have increased the atmospheric albedo and lowered ground temperature.  Also, large amounts of dust trapped in the Earth's meteoric veil would have reduced the insolation intensity to the Earth.  Either of these effects, or a combination of them, would have caused global temperature to gradually drop, producing the Younger Dryas cold period.  In the event of a global conflagration, the soot-filled air would also have had a cooling effect by temporarily reducing the amount of solar radiation reaching the ground.  [Evidence that the 200 year cooling trend at the onset of the YD occurred in step with the rise of atmospheric radiocarbon suggests that of these various effects the solar cosmic ray cooling effect was the lead cause.]  The influx of cold glacial meltwater and formation of North Atlantic sea ice during this period would have shut down deep water production and helped to maintain cold temperatures during the remainder of the Younger Dryas.

10. Eventual expulsion of the invading cosmic dust from the solar system would have returned the solar system to its present condition allowing the ice sheets to melt and recede.

So the demise of the megafauna would have been due to a number of factors:
  Death or illness due to an excessive dose of ionizing radiation, both UV and cosmic ray, due to elevated solar flare activity and a ground-contacting solar proton event.
  Death due to famine since vegetation would have withered during the cool arid Younger Dryas climate and preceding Intra Alleröd Cold Peak.
  Death due to heat stroke and smoke inhalation from exposure to the firestorm that produced the black mat layer evident today in North America and Europe.
  Death due to drowning in the glacial meltwater deluges that swept across the continent.
  Death due to poisoning by noxious fumes released from the meteoric ice vaporized in the atmosphere.

     While the superwave scenario may seem complex to some people, it nonetheless involves a sequentially connected chain of events, one necessarily leading to the next in inevitable fashion.  The scenario proposed by Firestone and West is conceptually simpler, but avoids/neglects considering the bigger picture of what was happening in the solar system with interplanetary medium and the Sun, and it ignores events taking place in the much larger Galactic neighborhood including evidence of recurrent cosmic ray outbursts originating from the Galactic center.  Also their theory does not take take into account events recurring over a much longer time period, as evidenced by cosmic dust peaks or beryllium-10 spikes that recur frequently throughout the last ice age cycle and, more generally speaking, throughout the geologic record.  Although Firestone and West to some degree delve into events occurring in the immediate Galactic environment with their proposal of a single nearby supernova occurring around 41,000 year BP which they propose as the source of their proposed comet onslaught, there are substantial problems with that proposal which are discussed below.


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