Category: the flood

Categories
rivers the flood

Of Catastrophic Floods and Canyons

Looks like in Texas, we just got to see a catastrophic flood in action and have some fresh land forms to look at. This is really, really cool. Catastrophic floods aren’t events that can be produced on demand1, so being able to watch one happen and be on site as soon as the waters recede to check out the alteration to the surface features is a very neat opportunity.

I’m less thrilled about some of the writing in the article, however. For example, this:

Our traditional view of deep river canyons, such as the Grand Canyon, is that they are carved slowly, as the regular flow and occasionally moderate rushing of rivers erodes rock over periods of millions of years.

Such is not always the case, however. “We know that some big canyons have been cut by large catastrophic flood events during Earth’s history,” Lamb says.

While I do understand what the author is trying to say, they’re frankly doing a poor job of it that plays right into the sticky little hands of the Young Earth Creationists; the author makes it sound as if this example of catastrophic flooding somehow sheds doubt on to what we know about the Grand Canyon. It doesn’t.

Catastrophic flooding and canyons is a fairly recent area of research that was pioneered by J Harlen Bretz – who was very much a geologist, not a young-Earth nut. He mostly looked at portions of the western US that were shaped by the glacial outburst floods from Lake Missoula during the last period of glaciation. One example of the resulting land forms is the Channeled Scablands. And the big canyons that Lamb is talking about? The coulees in that same area, such as Grand Coulee.

Morphologically, the coulees look VERY different from river canyons such as the Grand Canyon. As one example, viewed in an aerial photo, the Grand Canyon has very obvious (and incredibly entrenched) meanders – a river feature. Take a look at the Scablands and the features become much more linear – here you’re looking for the features that seem to slant NE to SW; Banks Lake, for example, was made by filling in the Upper Grand Coulee with water. And there are many other features that could be compared and found different between these canyons. If you’re curious, here’s an aerial view of the new “canyon.”

Which is why this really bothers me:

Unfortunately, these catastrophic megafloods — which also may have chiseled out spectacular canyons on Mars—generally leave few telltale signs to distinguish them from slower events.

…so do those boulders pictured in the article itself just not count? Because the idea that catastrophic flooding (such as glacial outburst floods) were the cause of certain types of features is relatively new, we’re still researching what features should be associated with what phenomena and trying to understand how they form. That is really not the same thing as there being “few” features, or that somehow slower erosional events are difficult to distinguish from flood events. Part of the elegance of Bretz’s argument for the Scablands was that the Lake Missoula outburst floods explained features that really couldn’t be explained by the normal action of rivers.

I have no doubt the YECs are already picking their way through the paper, taking the bits of data that support their position. That’s to be expected. But the way this article has been written makes me cringe. Instead of simply focusing on the super coolness of catching a flood like this in action, or giving background of other catastrophic flood morphology in the US, we’re getting these bizarre little pokings at the idea that this somehow affects our understanding of the Grand Canyon’s formation. Again, it really doesn’t. To me it just sounds like whoever wrote the article was searching for some sort of controversy or dramatic angle, one that was ultimately unnecessary when the solid facts are nifty enough to stand on their own. Writing FAIL.

1 – Okay, technically you could. But probably only if it involved an elaborate plot to blow up the dam upriver of Metropolis because you’re just so tired of your world domination plots being foiled. And you’d likely have to be cackling all the while too, and that’s just tiring.

Categories
the flood

The Grand Canyon of Durham

From the BBC: Floodwaters create ‘Grand Canyon’

As you might expect, this news item popped up on my Google alerts because of great flood references. It’s now been mentioned on at least a couple of forums where people have an interest in, shall we say, Not Real Geology. I’m actually surprised I missed this entirely until it popped up on Google alerts. The BBC is my news source of choice. Then again, it’s an article from last Friday, and Fridays tend to be busy days for me.

So… oh noes! A big flood created a canyon-like structure. Take that, geologists!

This is basically the same deal as the Mt. St. Helens “canyon.” The River Wear flooded and carved a new (but apparently temporary) channel into its own flood plain. The “canyon” is about four meters deep at most, which means it runs entirely through unconsolidated floodplain sediment. Sediment on floodplains tends to be pretty fine – about mud sized. This is why flood plains make such prime agricultural real estate.

Now, it must be said that it is a bit surprising for a river to carve itself a new channel in a single flood. (Though the bigger the flood, the more believable this becomes.) The floodplain sediment isn’t consolidated, but the farther down you get, the more densely packed it will be due to the weight sitting on top of it. It’s not quite the same situation as the fresh ash layer at Mt. St. Helens.

However, this also may not be a new channel. Apparently locals think that this might actually be a disused channel of the river, which was diverted by monks in the 15th century. In that case, if it’s an old channel that was simply filled in by enterprising monks, the relatively new soil in the filled channel would probably be a lot easier for the river to wash away than the older soil of the flood plain.

So no. This is not any kind of evidence for a biblical flood. There’s still an enormous difference between a river cutting through unconsolidated sediment and cutting down through solid rock. It’s a pretty neat opportunity for anyone interested in the local soil, though.

Categories
creationism the flood

Uniformitarianism is dead! Long live catastrophism!

I had something pop up in my google alerts this morning, and it pointed to this article on creation.com. I don’t recommend clicking or reading unless you want a helping of brain hurt this early in the day. The part that was of interest to me reads:

By way of illustration, consider geologic formations in the Great Basin of the western United States. The vast horizontal layers of hydraulically deposited sedimentary rock are said to take long periods of time to accumulate, based on the assumption that the rate of deposition was always similar to that observed today in a typical river delta. This concept of uniformity may seem like a reasonable starting point when considered abstractly, but no steady-state river flow could possibly cover such a vast area; neither would it produce the violently buried and mangled bodies found fossilized in many rocks of the region. The present-day erosion conditions applied uniformly in the past could not account for the unusual formations of the Grand Canyon, mesas, badlands, and other canyons. By contrast, the catastrophic processes observed during and following the eruption of Mount St. Helens in the Cascades of Washington state produced a scale model of the Grand Canyon in a very brief period of time. Sediments were rapidly deposited and then suddenly eroded by pyroclastic steam, water, and mudflows in the area northwest of the summit. Now the canyon walls resemble others that are assumed to be of great age, even though they are known to be [merely decades] old.2

The point to be recognized is that science deals with observations of present states and processes, and can only discuss the prehistoric past. In the example of geologic formations of the Great Basin, the assumption of uniformity can be contrasted with a model of catastrophic tectonic, volcanic, and hydraulic activity that would accompany a global cataclysm such as the great Flood of Genesis. The observed eruption of Mount St. Helens demonstrated that rapid processes can produce effects commonly believed to require long periods of time, and thus gives credence, if not preference, to the concept that the earth’s geology did not require long periods of time to develop. Many puzzling formations can only be explained through cataclysmic forces. Similarly, other methods of estimating the age of the earth or of the universe apply assumptions about processes and rates that extend into the distant past. Regardless of how apparently compelling such dating methods may appear to be, the fact remains that they are built on assumptions that must be critically questioned and evaluated.

Wall of text crits you for 2K! (…sorry, little World of Warcraft joke there. You can slap me later.)

Basically, what he’s saying is:
– Strictly applying the observed depositional/erosional conditions of today to events of the past doesn’t explain everything perfectly.
– There’s evidence for catastrophism.
– Hey, there’s a canyon by Mt. St. Helens that’s like a scale model of the Grand Canyon and it formed in a matter of decades. Suck it, uniformitarians!

I’m not going to get in to the specific third claim here, because Talk Origins has already addressed it, and so very concisely. If someone actually stumbles upon this little bottled note in the vast oceans of the internet and would like me to get in to more detail than that, I definitely can.

What I really want to talk about are the first two points, because those are constantly belabored by creationists. There’s evidence for catastrophism! Incremental change doesn’t explain everything!

What this boils down to is a straw man, a disingenuous mischaracterization of uniformitarianism, and how geologists apply the principle.

So, what is Uniformitarianism, you ask? It’s the principle that as today, so in the past. It’s the assumption that the same laws of physics we’re operating under today are the same laws of physics there were over the billions of years of Earth history. It’s the principle that processes as we see and understand them today occurred in the same manner and to the same effect in the past.

What Uniformitarianism is NOT is the strict application of today’s processes to the past. It is not the assumption that if we cannot observe it in person, and in real time today, that it could not possibly have happened in the past.

If you were to apply Uniformitarianism in that manner, for example, you’d have no explanation for komatiite, which is an extrusive igneous rock from the Archean period. There are no rocks forming today that look like komatiite or have its same composition, because conditions on the Earth have changed over the last 2.5 billion years. In the Archean, the Earth was producing so much heat internally that it could produce a full melt of the mantle, and thus komatiite. Today, there’s only enough internal heat to allow for a partial melt, and thus we end up with basalt. So does that mean komatiite is impossible, because the Earth’s volcanoes aren’t spewing it forth today? No. And we understand why. Conditions have changed, following the same laws of physics and chemistry that we operate under today.

I’ve yet to meet a geologist who follows Uniformitarianism the way creationists like to envision it. Rather than assuming that nothing outside of the geologic processes of today could have possibly applied in the past, we instead use those processes to inform our understanding of the past. Creationists like to whine (yes, whine) that geologists refuse to accept that catastrophic events occur, because we’re uniformitarian sticks in the mud. This could not be further from the truth. Anyone that’s done even basic reading on volcanoes, earthquakes, glacial outburst floods, or landslides knows that catastrophic events can and do occur. We just don’t buy that your catastrophic event could occur because you’re incapable of explaining it without a flood (har har) of special pleading.

My favorite example of the reality of catastrophic geological events comes in the relationship between modern glacial outburst floods and the formation of the Channeled Scablands in Washington. (This was also my presentation topic for Skepticamp in Colorado this year.) The current scientific consensus about the Channeled Scablands is that they were formed by a massive, dare I say catastrophic, series of floods. The Cordilleran Ice Sheet formed an ice dam across the Clark Fork River, backing all that water up over a period of years to form Lake Missoula. (The old Lake Missoula bed is where present day Missoula, Montana is located. You can still see the old lake shore deposits in the hills.) When the lake became sufficiently big to partially float the ice dam (it was made of ice, after all) the dam failed catastrophically and the lake was able to drain in a matter of days. (If you’d like to read more about these giant floods, Discover the Ice Age Floods and Ice Age Floods Institute are a couple of good sites to start with.)

This theory of the Scablands formation is actually very new, and there was a lot of scientific pulling of hair and scratching at faces over it. This is obviously also not an event we have any chance of observing today, since it’s not the ice age, and the Cordilleran Ice Sheet is long gone. (Something for which the residents of western Washington State are no doubt grateful.) However, in modern times we can still observe glacial outburst floods of a much smaller variety, such as the floods from Hidden Creek Lake at the Kennicott Glacier. Research on these modern floods has certainly led to better understanding of how the ancient Lake Missoula/Cordilleran Ice Sheet floods worked.

Or look at it this way: Have we directly observed a Chicxulub-type impact event? I sure hope that we never will. But we’re still doing a lot of work on that and other impact sites, and we are using Uniformitarian principles, since the laws of physics that caused that meteor to hurtle into our planet are still most definitely in force.

So, Dr. Ashton, you are right. Strict adherence to uniformitarianism as you paint it explains very little of the past. And catastrophic events do occur. Strangely enough, geologists know and understand this concept well, and it’s created a robust body of evidence and theory to form our picture of the Earth’s 4.5 billion year geological history.

Unfortunately for you, we’re just a little too uniformitarian (the real sort) to buy the special pleading that the laws of physics have changed so that you can have your 6000 year old Earth.