These researchers have discovered a correlation between the processes that caused the Great Unconformity in the geological record and the Cambrian explosion. This relationship helps explain why God waited until the fifth day of creation to create animal life in the oceans.
“And God said, ‘Let the water teem with living creatures, and let birds fly above the earth across the vault of the sky.’ So God created the great creatures of the sea and every living thing with which the water teems and that moves about in it, according to their kinds, and every winged bird according to its kind. And God saw that it was good.”
Genesis 1:20–21 (NIV)
One of the persistent questions I have about the Genesis 1 creation account relates to the fifth day of creation: Why did God wait until day five to create animal life in the oceans? Why not earlier?
Genesis 1:2 describes Earth in its primordial state as a water world. It is not unreasonable to think that Earth could support animal life in the oceans at that time (or at least shortly afterwards). Yet, creation proceeds through four epochs—including the creation of land and the population of plants on the newly formed continents on day three—before animals appear in the oceans.
New work by geologists from the University of Wisconsin and Pomona College (Claremont, CA) help answer my question.1 And with this answer comes added support for the scientific accuracy of the Genesis 1 creation account.
The Cambrian Explosion
The Cambrian explosion describes a dramatic event in life’s history about 540 million years ago when 50 to 80 percent of the known animal phyla appeared over a relatively short window of time (perhaps as narrow as 2 to 3 million years). This event defies an explanation from an evolutionary standpoint, and yet, is precisely what one would expect the fossil record to look like if, indeed, a Creator brought animal life into being. In fact, the Cambrian explosion, a marine event, is reminiscent of the fifth day of creation, when God commands the waters to teem with life.
Still, many scientists are looking for a way to explain the Cambrian explosion from an evolutionary perspective. This motivated the work of the geologists from the University of Wisconsin and Pomona College. Based on their work, the researchers believe there is a close connection between the Cambrian explosion and the geological events that created the Great Unconformity.
The Great Unconformity
Unconformities refer to gaps in the geological strata in which rock formations of vastly different ages come into contact. The Great Unconformity refers to a gap in the strata of the Grand Canyon observed by John Wesley Powell in 1869. The gap Wesley discovered is between sandstone that dates around 500 million years in age and igneous and metamorphic rock that is about 1700 million years old.
Geologists believe that unconformities in the geological strata arise when sedimentary or igneous rock form in low-lying areas and are then subsequently eroded. As a result of this activity, originally deposited material is lost from the geological record. Eventually sedimentary deposits re-form on top of the remaining geological layers that were left behind after the erosion took place, resulting in a gap in the geological column.
The Great Unconformity and the Cambrian Explosion
Geologists from the University of Wisconsin and Pomona College propose that the erosion that caused the Great Unconformity stemmed from the repeated advance and retreat of shallow oceans across North America. This process would have deposited calcium, potassium, iron, and silica into the oceans, altering ocean chemistry at the time of the Cambrian explosion.
Some of the evidence they cite in support of their proposal is the presence of extensive glauconite beds in rock formations of the early Cambrian. This mineral is rich in potassium, silica, and iron and is relatively rare today. The researchers also noted that there appears to have been high rates of carbonate mineral formation in the early Cambrian.
It is interesting to note that animals (and other organisms) that make use of calcium phosphate (found in teeth and bones), calcium carbonate (found in invertebrate shells), and silica (used by radiolarians) are among the creatures that first appeared in the early Cambrian.
The geologists propose (in the context of the evolutionary paradigm) that the massive influx of these materials into the oceans forced the organisms in the water at that time—soft-bodied creatures—to evolve in order to handle excessive amounts of minerals. They suggest that perhaps these creatures developed ways to precipitate these compounds (via a process called biomineralization) to protect themselves from the potentially harmful effects of these materials. The geologists argue that once mechanisms for biomineralization arose, the organisms could develop new uses for the biomineral deposits, building shells, teeth, bones, etc.
In other words, the researchers claim that the massive erosion, which led to the Great Unconformity, triggered the Cambrian explosion.
Can Environmental Triggers Explain the Cambrian Explosion?
This is not the first time scientists have speculated on possible environmental triggers for the Cambrian explosion. Yet, it is important to avoid confusing a correlation between environmental changes and the onset of the Cambrian explosion with a cause-and-effect relationship. Just because the environment changed at the time of the Cambrian explosion doesn’t mean that it was caused by the change.
Based on the evolutionary mechanism, changes in the environment don’t cause evolutionary transformation. Environmental changes will indeed create new niches that, in principle, organisms can evolve to fill. But the source of the evolutionary innovation has to stem from changes in the genetic material. The genetic material will not change just because the environment changes, let alone evolve in a way that will take advantage of the new environmental conditions.
Case in point, just because the level of calcium, potassium, iron, and silica dramatically increased in the ocean, doesn’t mean organisms necessarily developed the capacity to precipitate minerals, let alone evolve the complex and highly coordinated genetic and developmental programs needed to make use of the minerals, which are needed to build skeletal features that integrate with an organism’s biology.
Yet from a creation model perspective, the correlation between the change in the oceans’ chemistry and the Cambrian explosion is intriguing.
Changes in the Oceans Chemistry, the Cambrian Explosion, and the RTB Creation Model
The Cambrian explosion represents the type of features one would expect to see if a Creator was responsible for bringing animal life into being.
According to evolutionary biologist Richard Dawkins, “In the Cambrian strata of rocks, vintage about 600 million years, are the oldest in which we find most of the major invertebrate groups. And we find many of them already in an advanced state of evolution, the very first time they appear. It is as though they were just planted there, without any evolutionary history. Needless to say, this appearance of sudden planting has delighted creationists.”
In this context, the correlation between the Great Unconformity and the Cambrian explosion could be viewed as a divinely orchestrated event. If the Creator was about to make animals that would possess shell, teeth, and bones, it seems reasonable to think He would ensure that the mineral resources needed to make these structures would be available on the Earth.
In other words, from a creation model perspective, the Great Unconformity didn’t trigger the Cambrian explosion, but was part of the Creator’s plan to set the stage for the creation of animals.
The Cambrian Explosion and the Fifth Day of Creation
The relationship between the Great Unconformity and the Cambrian explosion also explains why God waited until the fifth creation day, after the emergence of the continents (day three), to create animals in the seas. Complex, advanced animal life in the sea could not exist until continents formed. The erosion products from the land generated the mineral resources in the oceans necessary for marine animals to form shells, teeth, and skeletons. The erosion products undoubtedly altered the oceans’ pH levels as well, transforming it from acidic to near neutral pH. Continent formation also created shallow water environments, which allowed cyanobaceria (photosynthetic microbes) to flourish, increasing oxygen levels in the atmosphere. The increased level of oxygen made complex, advanced life in the oceans possible as well.
The sequence of creation events in Genesis 1, not only conforms to Earth’s natural history, but it makes sense from a scientific standpoint. The scientific prescience of the Genesis 1 account is truly amazing and is evidence of its Divine authorship.