geocreationism.com

According to the NASA Science News, “Tiny zircons (zirconium silicate crystals) found in ancient stream deposits indicate that Earth developed continents and water — perhaps even oceans and environments in which microbial life could emerge — 4.3 billion to 4.4 billion years ago, remarkably soon after our planet formed.”

This seems to contradict the conventional scientific widsom, that the ancient ocean formed from outgassing and meteors about 3.9 billion years ago, 500 million years later than suggested by the zircon crystals.  However, the existence of the zircon crystals does not mean there was no volcanism or even later outgassing.  After all, the zircon crystals, though formed in an ocean, were fossilized in magma.  According to NASA’s “The Earth Observatory“:

“Thus, the magma that eventually gave rise to the zircons might have been formed from what had once been sediments deposited on the floor of an ancient ocean.”

This begs the question however of what happened in between, from 4.4 billion to 3.9 billion years ago.  The NASA Science News article suggests that “…Until roughly 3.9 billion years ago, swarms of comets and meteorites whacked the young Earth often enough to occasionally vaporize the surface zones of the oceans and erase any life residing there.”  Consequently, “the earliest known evidence of microbial life on Earth comes from carbon isotope patterns investigated by Mojzsis and colleagues in 3.85-billion-year-old Greenland sediments.”  Astrobiology Magazine has a good article on this as well.

A more recent study published at sciencemag.com in 2005 however suggests this isn’t what happened at all.  It does not dispute that the Greenland Evidence is the earliest known evidence of microbial life.  It also does not dispute that meteors impacted the earth.  However, after studying the temperature and moisture requirements for zircon creation between 3.85 and 4.4 Ga (billion years ago), “The most notable feature of these results is the low and restricted range of temperatures which, taken at face value, implies water-saturated melting conditions.”  These temparatures hover around 800°C.  But, under the earth’s then-pressure of 250 atmospheres, even this high temperature is too low to support the ocean vaporization suggested in the NASA theory.  According to the study, this suggests the presence of an ocean within which volcanic and tectonic activity could occurr, throughout almost a 400 million year period:

“The present results substantiate the existence of wet, minimum melting conditions at 4.35 to 4.0 Ga inferred from mineral inclusion studies and are consistent with the early Hadean hydrosphere hypothesis.”

Unfortunately, the article doesn’t explain why higher temparatures could not have existed during periods when no zircon was formed, and fails address when surface temparatures decreased to habitable level. A previous study at the University of Wisconsin however did attempt to address these questions in 2000:

“The earliest direct evidence for surface temperatures < ~100°C and terrestrial hydrosphere is >= 3.8-Ga metasediment from southwest Greenland.”

So, they acknowledge that temperatures may have exceeded 100°C before then, as demonstrated by the zircon crystals.  But, was the hydrosphere always liquid, or always vapor for all that time?

“One constraint on the presence of a stable hydrosphere on the Earth is the extensive meteorite bombardment experienced in the Early Archean was decued from the lunar record.”

It goes on to explain why these impacts must be constrained to between 4.4 and 3.8 Ga, adding that “recent work has documented a strong peak in impact intensity at ~3.9 Ga,” after which time, the impacts appeared to have stopped altogether.  It is then explained that “a long-lasting hydrosphere is not necessary for water-rock interaction and granite production at 4.0 or 4.4 Ga.”  In other words, the zircon samples could have been formed “during intense meteorite bombardment, but between cataclysmic events,” meaning sometimes there was an ocean and sometimes there wasn’t.

Now, the sciencemag article argues that such vaporous periods could not have existed, because the cataclysmic events that caused them would have been much hotter than the 800°C that created the zircon crystals.  However, this just means the temperature at the time of the zircon formation was not more than 800°C.  It doesn’t necessarily preclude such temperatures before then.  Perhaps the zircons formed as the earth cooled off after the cataclysm.  And the sciencemag article still presents no explanation for the high pressure necessary to sustain the liquid ocean at 800°C.  But, the zircon did form at 800°C, and liquid water was required to do it.  So what happened?  The University of Wisconsin article explains that…

“…to have extensive hydration of primitive crust, large bodies of liquid water must be present to submerge midocean ridges.  Steam would be an inefficient mechanism to hydrothermally alter large amounts of ocean crust, because it is unlikely to convect through rocks due to its low density; thus, magmatic water would pass at most once through hydrothermal systems and be lost to the atmosphere.”

In other words, the zircon was formed from liquid within escaping earth, only vaporizing after its contribution to the zircon formation.  Consider then, with these events suggesting a cooling cycle after a vaporizing cataclysm, it is therefore quite likely that the vapor would in fact condense into an ocean that would endure for millions of years at a time… until the next cataclysmic meteor impact. 

The argument for an ancient ocean therefore endures, suggesting the waters God hovered over in Genesis 1:2 existed in the Hadean period.

We also know that the sky was dark, even up to 3.9 Ga. According to the Harvard-Smithsonian Center for Astrophysics:

“At Epoch 0 (3.9 billion years ago), the young Earth possessed a turbulent, steamy atmosphere composed mostly of nitrogen, carbon dioxide and hydrogen sulfide. The days were shorter and the Sun was dimmer [than today], shining as a red orb through our orange brick-colored sky. The one ocean that covered our entire planet was a muddy brown that absorbed bombardment from incoming meteors and comets. Carbon dioxide helped warm our world since the infant Sun was a third less luminous than today. Although no fossils survived from this time period, isotopic signatures of life may have been left behind in Greenland rocks.”

Genesis 1:2 reads, “And the earth was formless and void, and darkness was over the surface of the deep; and the Spirit of God was moving over the surface of the waters.”

This entry was posted on Thursday, November 16th, 2006 at 12:51 am and is filed under Bible Commentary, The Science. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.