Eroding Continents, Uniformitarianism vs. Catastrophism, and Young-Earth Creationism

Introduction

Recently, I’ve done a lot of posts on young-Earth creationism (YEC), and the majority of those have been based on the Institute for Creation Research’s daily “science” updates (or as the Eye on ICR blog calls them, “daily pseudoscience updates” or “DpSU”). As such, when yet another geology-related one came out this week, I was going to ignore it. Especially because said Eye on ICR blog already covered it (don’t you have homework, Peter?).

But then I read this particular “DpSU” again, entitled “Continents Should Have Eroded Long Ago,” and I decided that, actually, there was something I wanted to cover from it.

The Obligatory Summary and Wrongness of the ICR Article

I do have to briefly summarize these points before I get to the larger issue I wanted to address. Basically, in said article, the “science” writer Brian Thomas talks about a recent paper that estimates the rate of erosion of continental crust material. The paper, by Eric Portenga and Paul Bierman, is freely available for anyone to read and it is in a legitimate publication (as in it’s not something like the “Answers Research Journal” or “Creation Science” or “Origins”).

The paper itself is actually somewhat interesting. It’s about 7 pages long, has big pretty full-color images, and may be somewhat understandable to someone without any background in the field (I do apologize, but even though I swore I never would, I do lose track of how much background the general public has in these areas). I should also note that this paper is a metanalysis of previously published data, so the authors themselves did not go into the field but rather pulled a lot (1599) numbers from the literature. The paper was really comparing two different erosion rates, that of rock outcrops to those of basins. To quote the very first page, they found “Drainage basin and outcrop erosion rates both vary by climate zone, rock type, and tectonic setting.”

But, they calculated an average erosion rate of 12±1.3 meters per million years (or 12±1.3 micrometers per year) though the median was 5.4 µm/yr. This large difference of a factor of ~2x between the average and median (median is the middle number of a sorted list) indicates that the data are highly skewed towards lower erosion rates. They found erosion rates within drainage basins to be about a factor of 20x larger with a 218±35 meters per million years (218±35 µm/yr) average, or 54 µm/yr for the median (again indicating a skew towards slower rates). They then discuss variations in different locations, as I mentioned in the previous paragraph, and have more discussion in the paper than I want to put here.

So, that’s what the authors of the paper found.

Where Mr. Thomas comes in is the following: “According to the study, the average erosion rate for outcrops was 40 feet every one million years. The average thickness of continental crust above sea level can be estimated at about 623 meters, or 2,044 feet. To erode 2,000 feet of crust at 40 feet per one million years would require only 50 million years. So, if the earth is billions of years old, why is its surface not completely flat?” He does the same with basins and claims that this puts a limit at 3 million years.

He then shoots down the idea that geologic uplift is happening with a 1986 paper by a creationist in a creationist publication and then states, “The fact that mountains and even continents still exist is testimony to the young age of the earth. It looks as though the continents cannot be billions of years old, because they would all have eroded in a fraction of that time. And yet they still stand tall.”

Well, one problem with this is simply that, even if we assume everything he wrote is true, we could still easily have a million-year-old planet, no problem, not a 10,000-year-old one.

Another problem is simply that he’s wrong wrong wrong. Did I mention he’s wrong? He ignores things like isostasy where regions of continents are still moving upwards from the last ice age. He ignores volcanism and how volcanoes build mountains (do I really have to cite a source for that?). He ignores that fact that non-volcanic mountain ranges are still growing, where, for example, the Himalayans are growing at a rate of about 6 cm/yr (2.4 inches/year). For those who are really really bad at math, 6 cm/yr is much larger than 5 µm/yr — larger by a factor of 12,000. More than enough to keep up with erosion.

Now, I really don’t think I have to go much further in showing the sheer willful ignorance of Mr. Thomas on this topic. But this feeds into a much larger one that is near and dear to every YEC’s God-given heart.

Uniformitarianism versus Catastrophism

I can almost guarantee that you will never hear the terms “uniformitarianism” nor “catastrophism” unless you pay attention to creationist writings or you delve very deep into the history of philosophy of science or, specifically, geology.

Over-simplified, uniformitarianism is the notion that all processes that exist now are the same as they have been. Creationists assume this when they say the Moon cannot have formed 4.5 billion years ago because it is currently moving away from Earth at a rate of about 1 inch per year and if you run the numbers backwards (assuming uniformitarianism), then it crashes into Earth way before 4.5 billion years ago.

In contrast, catastrophism is the opposite, where rates of change will change, sometimes being faster and sometimes slower.

What I find fascinating is that YECs will use catastrophism to explain practically everything in their view of natural history. God stretched out the heavens so we get away from the “distant starlight problem.” God made the world and all that stuff in a day or two so we don’t have to deal with formation times of the solar system. The flood explains the Grand Canyon, sedimentary rock layers, Earth’s magnetic field reversals, and lots of other things. All fall under catastrophism.

As a consequence of this embrace, they deride us evilutionists for assuming uniformitarianism. Hence uniformitarianism is assumed with the speed of light, universal constants, radiometric dating, continental drift, etc.

And yet, when given the opportunity to take a bit of modern science and twist it to their own agenda (as in the case of this paper), they assume uniformitarianism! Thomas’ assumption that the basins would be flat within 3 million years is based on the currently observed rates. Same with the continents. And same with several other topics I’ve addressed in this blog over the past three years.

Final Thoughts

I realize that those of you who are not YECs are going to read the above section and think, “What do you expect? Creationists are never consistent with the facts, they distort them to suit their argument-of-the-minute.”

Fair enough. But, I find it enlightening and, yes, even slightly exciting to find yet another inconsistency in their arguments. Granted, the argument in the particular article of this post is completely wrong based on very basic geology that I think most third graders have learned (if you know about volcanoes, you know his argument is wrong). But, it also exposes this inconsistency.

When it suits them, the catastrophic Flood explains everything we can throw. But when it suits them, they take a modern scientific measurement, assume a dramatically flat uniformitarian extrapolation, and hence show that Earth can’t be as old as it is.

Now, it’s been awhile since I’ve pointed out formal logical fallacies, so correct me if I’m wrong, but I think there are two basic ones here. The first is a reductio ad absurdum where he’s reduced the study’s results far beyond what the authors intended. The second would be a basic straw man where, as a consequence of reducing the study to something stupid, they’re extrapolating it to argue a point that is obviously false but was never intended to be made.

Edited to Add …

I can’t believe I left this out, that that plucky guy over at Eye on ICR pointed it out quite well: The paper that Mr. Thomas is pulling the latest erosion estimates from relied upon ¹⁰Be-based ages. It’s not important to go into the mechanics for this particular method here, suffice to say this is a radiometric-based age. But, wait a sec, creationists – including Mr. Thomas – very frequently argue against radiometric ages because they seem to think they don’t work! (Check out, for example, “Radiometric Dating: Making Sense of the Patterns” from AiG, “Radioisotopes and the Age of the Earth” from AiG, “Feedback: Dating Techniques” from AiG, “Fluctuations Show Radioisotope Decay Is Unreliable” from ICR, “The Sun Alters Radioactive Decay Rates” from ICR, “Dating in conflict: Which ‘age’ will you trust?” from CMI, or “Nuclear physicist embraces biblical creation” from CMI, if you don’t happen to believe me.)

So yeah, I guess we can believe radiometric dates when they support creationism, but otherwise they’re wrong and full of flaws. Hmm. This is actually something that I often point out when I give a public lecture on these kinds of topics, and one that I’ll be doing when I give my Apollo Moon Hoax talk in a few days: Science presents a cohesive story. Pseudoscience does not. You either have these flaws in radiometric dating that doom it (as creationists almost always argue), or you can trust the scientists to know what they’re doing and take the results from that (as Thomas is doing in this one instance). You really can’t have it both ways.