The Erosion of Continents as a Creationist Clock

By Peter Fischer

The continents erode too quickly for the Earth to be any older than 15-16 million years. This is but one of the many claims that some Young-Earth Creationists have used in contention to the scientific community's established view that the Earth is roughly 4.5 billion years old (Dalrymple 2004: 1). Backed by a handful of statistics and some overly simplistic reasoning, a number of Young-Earth Creationists argue that since the continents still have considerable elevation, the earth is relatively young.

erosion and deposition based on topographyIn terms of a natural clock, this claim presupposes that erosion is an irreversible process. Additionally, the claim maintains that the rate of erosion is constant and has remained constant since the formation of the Earth. By using the rate of erosion as a clock, these Young-Earth Creationists believe they have determined the origin of the earth – their initial condition – to be much younger than 4.5 billion years.

To evaluate this claim, one must take into account the statistics which support the claim in question. For one, erosion measurements show that the continents are lowered by wind, rain, hail, waves, and living creatures' activities (Ross 2004: 186). This piece of information is rather intuitive; there is nothing to dispute here. However, the Young-Earth Creationists arguing that the earth is very young must still somehow show a causal relationship between the erosion of the continents and a young age of the earth.

Attempting to show this relationship, they point out that the rate of erosion is approximately .005 millimeters per year and that the continents average about 800 meters in elevation (Ross 2004: 186). One such group, the Horizon Christian Fellowship in San Diego, California, actually produced a handout containing the following:

"Each year, water and winds erode about 28 billion tons of dirt and rock from the continents and deposit it in the oceans. At that rate, it would take only 15 million years to erode all land above sea-level. Yet most of the land is supposed to have been above sea-level for hundreds of millions of years" (Macon 1996).

The Horizon Christian Fellowship cites this information as a "compelling reason" to reject an old earth (Macon 1996). These Young-Earth Creationists reason that at this rate of erosion, the continents would have been eroded flat in well under 16 million years. Clearly then, the evidence must point to an earth younger than 16 million years, right?

Not exactly. This claim focuses on only one side of the equation. The main reason the claim is unfounded: it fails to acknowledge all of the factors that build the continents up. In other words, the process upon which the clock is built is reversible. To expand on this, these particular Young-Earth Creationists fail (or simply refuse) to acknowledge the consequences of lava flows, delta and continental shelf buildup, and uplift from colliding tectonic plates. This rate of buildup occurs at rates roughly equivalent to, and in some cases exceeding, the erosion rate (Ross 2004: 186). Consequently, the claim that the continents erode too quickly for the Earth to be any older than 16 million years is without basis for scientific credibility.

path of the Indian subcontinent leading up to its collision with AsiaFor example, it is easy to see many cases where the Earth is being built up. When considering the Himalayas, these mountains in South Asia rise by more than one centimeter per year due to the tectonic collision of India with Asia (USGS 1999). Another example would be that of Hawaii. Lava flows have increased Hawaii's land area by several square miles over the past 50 years. In one specific instance, as of January 2005 the eruption of Kilauea had produced 2.7 km3 of lava which covered 117 km2 and added 230 hectares to Kilauea's southern shore (USGS 2005).

To put the claim in the context of the geologic/sedimentary record as a whole, it is important to note there are sequences of layered sedimentary rocks several miles thick. Conversely, in other places there are no sedimentary rocks at all. It is important to note that some places on continents undergo uplifts while others are actually sinking (Dalrymple 2004: 29). This suggests that there are cycles of deposition, uplift, and erosion, which probably do not take place at a uniform rate. Therefore, the rate of erosion is far too variable to make an accurate clock.

Also central to this creationist claim is that the initial condition measured by the rate of erosion must be the origin of the earth. However, because of the constant cycle of deposition, uplift, and erosion, there is no definitive initial condition. Moreover, even if one could derive an initial condition, such a condition would be dating an event much younger than the formation of the earth.

Ultimately, there are simply too many unknown variables to support this Young-Earth Creationist claim. Perhaps, in a time when little was known about tectonic plate activity, lava flows, or land buildup in general, this claim could have maintained some sense of credibility. However, as it stands, given our current knowledge of erosion vs. continental buildup, the continents do not erode too quickly for the earth to be 4.5 billion years old.

Sources:
  1. Dalrymple, Brent G. 2004. Ancient Earth, Ancient Skies. Stanford: Stanford University Press, 1, 28-29 p.
  2. Macon, Michael D. Creation and a Young Earth. http://home.wmis.net/~ixthys/caaye.htm. Last Updated: 1996. Accessed: Oct 17, 2005.
  3. Ross, Hugh. 2004. A Matter of Days. Colorado Springs: NavPress, 186-187 p.
  4. U.S. Geological Survey. 2005. Hawaiian Volcano Observatory (HVO). http://hvo.wr.usgs.gov/. Last Updated: Sept. 1, 2005. Accessed: Nov. 1, 2005.
  5. U.S. Geological Survey. 1999. The Himalayas: Two Continents Collide. http://pubs.usgs.gov/publications/text/himalaya.html. Last Updated: May 5, 1999. Accessed: Nov. 1, 2005.