Sedimentology and Young Earth for Creationist Dummies

Grand Canyon sedimentary rocks

Every few months we stumble over one of our oldest files of potential DotD candidates. Most of the posts listed in the file have already been featured here, although not a few have been deleted by the website – or the website itself has gone belly-up. A few, however, persist; and today's nominee is one such post. Our guest is someone who's been hanging in there at HubPages.com for at least three years. Give a warm welcome, readers, to Lawrence Hebb and "Young earth evidence: the sedimentary rocks."

Hebb appears to have started his HubPages account mainly to shill for a buttload of self-published thrillers (Scorpion xxxxxx), but along the way he also managed to inflict his own peculiar brand of misinformation on the site. This time out, the evangelical Christian attempted to make war on the science of geology, disproving "evolution scientists" by explaining where they got it wrong. His evidence? sedimentary rocks.

Larry opened by explaining rocks, in which he outlined the rock cycle. If you believe Hebb, the cycle is:

1. "Igneous rock... came straight out of the Mantle [sic] of the earth and had not been changed. A classic of this [sic] is a lava flow."
2. "Once the water or weather patterns have begun to work on the igneous rock and worn it down then sedimentary rock is formed."
3. "Metamorphic rock... is rock that has come under stress from either heat or pressure and changes. Quartz and Diamonds [sic] are metamorphic rocks."

Except for the utter bull about igneous rocks coming "straight out of the Mantle" and "Quartz and Diamonds" being metamorphic rocks, those are the basic rock types. Where Larry got confused is that he didn't seem to understand that any rock can be melted, eroded, or metamorphosed: it's not a simple progression of igneous to sedimentary to metamorphic. Hebb, then, seemed surprised that,

"It's estimated that in one year erosion produces between twenty and twenty five billion tons of sedimentary rock. That's just in one year! Yet in all that time only 8% of the earth's rocks are sedimentary! If the earth has had weather patterns to make erosion for 3 billion years then were is it all?"

We'll get to that later, Larry... But here's the kicker: Hebb's argument that sedimentary rocks prove his young earth theory is quite simple, albeit terribly uneducated:

"If erosion has been happening for the past three billion years and water has created about twenty billion tons of sediment every year then there should be a lot more sediment than there is. The total sediment produced by erosion should cover the earth and be thousands of feet thick, but it only covers a small part of the ocean and only to a depth of a few hundred meters."

We're really not sure where he got his "few hundred meters" crap,¹ since there are plenty of places in the ocean basins – especially near the continents – where sediment thickness exceeds 10,000 meters².  Hebb then offhandedly dismissed the entire theory of plate tectonics and the dynamic earth, along the way misinforming his readers that,

"The tectonic plates move about two millimeters (one eighth of an inch) every year. Some years they don't move possibly for decades but then suddenly they move with devastating results 'EARTHQUAKE' is the earth's way of renewing itself."

To which we say, A) all plates are constantly moving. Earthquakes are not the result of sudden plate movements, but of the release of local stress caused because rocks break instead of bend. B) No plate moves only 2mm per year: the average appears to be between 5 and 10 cm per year. Hebb also seemed to think that the only way sedimentary rocks are recycled is at subduction zones. The stupidity of that assumption is astounding: anyone who ever been to someplace like the Grand Canyon (see image above) should be well aware that the sedimentary rocks in that photograph are being recycled into sediments that will ultimately end up in the Gulf of California.

Because he assumed that the sedimentary rocks present in the ocean basins represent all of time, Larry calculated that the Earth is about 12,000 years old. Given that Hebb's entire argument finds its basis in the erroneous, simplistic assumption that every sedimentary rock that was ever formed is still kicking around somewhere, we feel perfectly justified in presenting to this ignorant fool the singular honor of a Dumbass of the Day award. We'll be frank: willfully ignorant people just plain piss us off. That's the reason why all the Amazon links are for geology books for kids. He needs to start at the beginning... ¹ Actually, we are: the average thickness of sediments in the ocean basins is 300m, on land it's 1.8km ² Examples: Mississippi delta, Niger delta, North Sea, South China Sea...

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SI - GEOLOGY