Well hello again! Today we will be looking at a little bit of plate tectonics and the early formation of life as we continue to look at the Biblical account of the days of creation. (If you are interested in the earlier parts, here are the links: Part 2 and Part 1)
And God said, Let the waters under the heaven be gathered unto one place, and let dry land appear: And it was so… And God said, Let the Earth bring up grass…
When we last looked at the Earth is was mostly covered with water. Comets, asteroids and volcanic outgasing had given the Earth enough water to form an atmosphere with water vapor. As it cooled, the water fell from the skies and saturated the Earth, creating Earth’s oceans. The elapsed time that we have had so far is something like 3,000 million years. It’s time to get some dry land. (Now I have to admit right now that I am not much of a geologist, so I’ll be giving a much simpler explanation of how the continents were formed. I feel that a person should not talk about anything he does not know, so I won’t be going into too much detail here.)
The Earth by this point had cooled down significantly from its molten beginning, however at this period of time, the Earth’s mantle was quite a bit hotter than it is now, so subduction and plate tectonics occurred on a much faster pace than they do today. Early tectonic plates began to form as the crust of the Earth shrunk due to its cooling and its heat began to experience mantle convection, the process in which heat from the crust flows to the center of the planet. At this point, the geologic events that characterize our Earth began to happen.
Earth was still covered in water, but subduction began to gradually move parts of the crust above the surface. Subduction is the process by which land masses are formed. When two large plates of the Earth’s crust come in contact with them, the pressure and force of the collision forces one of the plates to move under the other. The plate that is submerged gets melted and becomes part of Earth’s molten mantle while the plate that prevailed is pushed upwards, essentially on top of the other plate. This is how our continents were formed over a long period of time.
The Biblical verses tell us that the waters were gathered to one place and the land presumably in the other. This matches the current understanding of the formation of our land masses. Most people have heard of the supercontinent Pangaea. What most are unfamiliar with is that Pangaea is simply one of many supercontinents that formed during Earth’s prehistoric period. Throughout the prehistoric era of Earth’s history, supercontinents were constantly being formed and destroyed, and scientists are able to theorize how they all fit together as they trace fossil patterns and prehistoric rock patterns. Although the last supercontinent broke up a millions of years ago, we can see this trend continue with Eurasia, which can be classified by a supercontinent.
So what about that grass? Well this is where my knowledge really grows thin, because I am not much of a biologist. It seems evident though that as soon as dry land was available, plant life was able to grow on it. It is likely that plant-like organisms had existed in the ocean before dry land emerged, but plant life as we (and the ancient readers of the Biblical text) understand it had to wait until it got to dry land. I would be curious to know what the Hebrew word was that translated as grass. But at this point of history we can be sure that life was flourishing. (I will talk a little about evolution in a subsequent post).
Well there we have it. Dry land and grass. Tune in next time for visible stars and the moon!