Monday, July 23, 2012

Dr. A's course in Geology arrives at Continental Drift

In the Geology Course Dr. A has been presenting at EvC for some months now, he's arrived at a history of the concept of Continental Drift, which will lead next to a discussion of Plate Tectonics as the means by which the continents do their drifting.

He does a very good job on the history of the thinking in the field that led up to and finally accepted the proposition that the continents are in fact moving apart. In my opinion this is maybe the best post he's done in this series, showing with much clarity how science works.

But of course there's always something a mainstream scientific treatise has to say that a creationist must disagree with, and as is often the case, it has to do with timing:
First there is the fact that the continents are moving right now, as can be measured by GPS (the Global Positioning System), by SLR (Satelite Laser Ranging), and by VLBI (Very Long Baseline Inferometry).

Moreover, the continents are moving at the right rate. That is, if we apply geological dating methods to see how long ago the Americas parted from the Old World, if we measure the distance across the Atlantic, and if we measure the rate of drift using GPS, SLR, and VLBI, we find the numbers to be consistent.

If this in itself is not conclusive evidence that the continents have been moving for millions of years, it is at least highly consistent with that proposition.
In this part of his discussion he hasn't actually said (a flaw in his presentation) that "the right rate" is a constant rate, but given that the rate is known to be extremely slow (he doesn't give the figure -- another flaw -- but 2-4 inches per year is I believe the recognized rate), and that the rate as he says is "consistent with" millions of years of continental drift, we can assume that this very very slow rate which is observed to be occurring now is what they have in mind for the rate of travel over all of those entire millions of years. A uniformitarian assumption.

I don't know, I haven't done the calculations and it could be that it isn't really all that consistent with their assumptions, but I'll accept that it is for the moment.

But I did in an earlier post on this subject make the calculations based on the worldwide Flood as the starting point for continental drift. The idea is that the continents split apart as a result of geological disruption of some sort connected with the Flood, some 4300 years ago, probably volcanic eruptions along the lines where the land mass split into separate continents, a disruption violent enough to set the continents adrift at a much greater rate than that at which they are still continuing to move apart. The starting rate I came up with was 1-1/2 miles per year, or 20 feet per day, which slows to the current 2-4 inches per year in the 4300 years since the Flood.

As part of the evidence for Continental Drift, Dr. A presents a diagram of the distribution of certain fossils that only makes sense if the continents were once joined as the diagram shows they most likely were at one time. Since the vast majority of the world's fossils are a record of life forms that lived before the Flood and died in that catastrophe the diagram probably gives at least a rough picture of how those life forms were distributed in the pre-Flood world --assuming the Flood didn't carry them far from their usual habitat anyway. Second thought -- based on the long narrow shape of the fossil distributions -- is that the distribution might say more about the movement of the Flood waters than the original habitat of the flora and fauna. But either situation does require the land mass to have been united in some such pattern as the diagrim illustrates for the distributions to be coherent.


  1. I'm curious wouldn't your calculations of rapid movement of the crust result in higher volcanic activity at subduction zones which would decrease over time?

  2. There is higher volcanic activity at subduction zones as a matter of fact, isn't there?

    But although volcanoes at the subduction zone may decrease over time, wouldn't new volcanoes arise as the continent continues to move as well? At the rate of an inch or two a year new ones won't occur at anywhere near the frequency as they did when the movement was faster, however. If I'm understanding what you are saying, and even if I do I'm not sure I understand what point you are trying to make.


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