The stratigraphic column — not a figment of geologists’ imaginations

I have been involved in an online discussion regarding whether or not the geologic column (Cambrian-Ordovician-Silurian-Devonian…) is real, or  some sort of figment of geologists’ imaginations. Dr. Jay Wile, on his Proslogion blog, has written a post entitled Yet Another Failure of “Geological Column” Reasoning. Please note that I consider Dr. Wile (author of the Apologia series of home school science textbooks) to be one of the better young-Earth creationists; one who is willing to point out the scientific and theological shortfalls of the overall YEC movement when he sees them.

Dr. Wile argues that the discovery of fragments of grass phytolyths (tiny glass particles in grass leaves) in Cretaceous dinosaur dung (coprolites) is evidence that the whole concept of the geologic time scale is in trouble. After all, we had been told rather authoritatively that there were no grasses in the Cretaceous; that grasses did not appear until a few million years after the demise of the dinosaurs. He draws a parallel between this and another “failure” of the the geologic column: living fossils such as Coelacanths. If the geologic column is built on fossils, and if we discover that some fossils occur later or earlier than we realized, then perhaps the geologic column itself is suspect.

In the comments on Dr. Wile’s blog post, I have argued that the geologic column is more of an observation than an inference. I realize from philosophy of science that observations can be highly biased; that we often find just exactly what we are looking for. The young-Earth creationists claim that this is exactly what has happened; that geologists, imbibed with evolution, were expecting to find some sort of evolutionary order in the fossil record, and therefore they went out and found it. When one points out that the geologic column was largely deciphered before Darwin, they respond by saying that there was plenty of evolutionary thinking before Darwin (e.g. Lamarck), and that this is what influenced the early stratigraphers.

One of William Smith’s geological maps. From Wikipedia: William Smith (geologist)

But is this what happened? Were the early 19th century geologists more influenced by evolutionary thinking, or by what they observed in sedimentary rocks?

In the early 1800s, William Smith compiled the first geologic maps of Great Britain. At first he focused on types of rocks, but he soon recognized that there were distinct fossil assemblages in the layers as well, and that these too could be traced across Britain .

Within the upcoming decades, scientists across Europe, and then in North America and elsewhere, began to make similar geological surveys. They discovered that not only were many fossils restricted to narrow bands of rock, but that there were many types that no longer could be found on Earth, and that there were consistent patterns in the order in which these fossils appeared in the geological record. This led to the construction (or discovery) of the geologic column. They eventually put labels on parts of the geologic column, such as Ordovician and Triassic.

Some of these early geologists were Christians, some were deists. Many were catastrophists, believing that the sedimentary rocks were the product of worldwide deluges, and many believed in the fixity of species. Few had the molecules-to-man picture that emerged after 1859.

That is a very brief summary of the development of the idea of the geologic (or stratigraphic) column, which is closely tied to the concept of geologic time. I want to make the case that the geologic column exists, that it is in need of an explanation, and that the standard geological explanation of deposition over millions of years works well, while that of the YEC Flood geologists falls far short.

The basic concept of the geologic column is that sedimentary rocks occur in the crust of the Earth in a specific sequence, and that this sequence has a global, rather than regional, basis.

Let’s start with the stratigraphic section that might be found at one location. This section would be a slice through the Earth. It might be exposed in a canyon or on a mountain side, or detailed by examining cores and cuttings as a well is extended deeper into the crust. My initial column (A) has five layers, which I will label 1, 2, 3, 4, and 5.

I am not all that concerned at this point whether those layers are sandstone, shale, or limestone. Instead, I wish to focus on the fossils. Layer 1 might contain marine fossils, such as trilobites and brachiopods. Layer 2 might also contain bryozoans and brachiopods, but of different genera than those found in layer 1. Layer 3 might contain corals. And so on for layers 4 and 5.

Now lets move down the road fifty miles and examine another section (B) of the sedimentary record.

Some of the layers clearly connect from A to B. This could be in terms of the rock types, the fossils, or both. But B has six layers, with B4 appearing between what was A3 and A4. Note that the correlation lines do not cross. This is not because of some evolutionary presupposition, but because the fossils in A1 match the fossils in B1, the fossils in A4 match the fossils in B5, and so forth.

Let’s move over one or two counties, and examine a third series of layers, section C.

We can see that A1 correlates with B1 and C1. B2, however has disappeared somewhere between B and C, and a new layer, C6, has appeared at the top of the section. Note again that there is no crossing of the lines.

For a final look, I’ll add two more sections, D and E.

It is apparent that some layers correlate all the way across from A to E, others pinch out, and still others appear. Once again, there is no crossing of lines.

These are all hypothetical columns of rock. In the real world, the same types of patterns occur, and geologists have given names to sets of rocks, based on the fossils that they contain. The lowermost layers contain distinct assemblages of fossils that have been given the label “Cambrian.” Higher in the column, another distinct assemblage of fossils has been named “Ordovician.” This continues upward for the entire geologic column.

Credit: NPS & USGS

Don’t get distracted by the numbers at this point. I am not defending so much the age of the Earth right now, but the reality of the geologic column, and I have this diagram here as an illustration.

The well-read young-Earth creationist, at this point, will say that this entire column does not exist in any one place; that it is all an inference. Look at the Grand Canyon, for example. It only contains fossil-bearing rocks from the Cambrian, and Devonian through Permian (no Silurian, Ordovician, or anything younger than the Permian).

Credit: NASA

That objection is pretty easy to answer. First of all, if one looks at the broader context, the Cambrian through Permian rocks of the Grand Canyon can be traced laterally to where they are beneath rocks in Utah that have Triassic, Jurassic, Cretaceous, and Tertiary fossils.

So in a distance of roughly one hundred miles, we can trace most of the periods of the geologic column. All that is missing is the Ordovician and Silurian. There are Quaternary deposits in this area, they just are not shown on the diagram. This sort of situation—correlation of layers—is the rule rather than the exception.

Second, there are a number of persistent sedimentary basins—areas that for one reason or another have continued to collect sedimentary deposits through much of geologic history—that do indeed contain layers from each of the geologic periods. If one drills into the Williston Basin (North Dakota, Montana, Saskatchewan), they will find the layers in the proper order. Starting from the bottom, there are layers from the Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Tertiary, and Quaternary. There is nothing out of order. This can be seen on the following stratigraphic correlation chart.

Credit: Core Lab —

This really is a nice looking correlation chart; I encourage you to look at the full-scale version at the Core Lab web site. This chart (and others like it) show the same thing that I was doing with sections A-B-C-D-E earlier. Note that in the Montana and North Dakota columns at the far right of the chart, there are rocks from the Cambrian all the way up through the Quaternary. This chart only covers a corner of North America (British Columbia to Manitiba and down into parts of the United States). It could easily be extended to the whole of North America, and even to Europe and the rest of the world.

Note that the fossilized rocks express the same order no matter where you go. You simply do not find Cambrian rocks lying on top of Jurassic rocks. There is no crossing of the correlation lines. (Side note: YECs will often point to areas where older rocks are above younger rocks in areas that have been deformed by folding and faulting. If you undo the deformation, everything always slides back into place).

One can go to a number of basins throughout the world—in Libya, Bulgaria, China, Australia, Colombia, and elsewhere—and find exactly the same thing. It is not Cambrian-Ordovician-Silurian-Devonian in North America, and Permian-Cambrian-Devonian-Ordovician in Europe.

Many of the better young-Earth creationists acknowledge that there is some sort of order to the fossil record. They know that there are only invertebrates in the lower parts of the column, that land vertebrates (amphibians and then reptiles) don’t show up until the middle, and that mammals don’t show up until the top part.

At the simplest level, there was the proposal that marine organisms got buried first, and then the slow moving amphibians and reptiles, and the mammals and birds, who were quicker, were able to run faster (or fly) and so escape the earlier Flood waters. But this verges on being nonsense, as there are terrestrial sediments deposited throughout the column. And there are lake deposits, and shallow marine deposits, and deeper marine deposits also scattered throughout the column. And am I supposed to accept that all mice were able to outrun the advancing Flood, but pterodactyls couldn’t?

More sophisticated models have come along, such as various horizontal and vertical ecological zonation models. These models run into some of the same problems, as well as some additional ones. First is the problem of sorting. I would expect a worldwide Flood to at least sometimes have some turbulence, and to either mix groups of fossils together, or to put them out of order. Maybe even a little tiny bit. But it doesn’t seem to have happened. The order is Cambrian-Ordovician-Silurian-Devonian…  It isn’t Cambrian-Ordovician-Mixture-Mixture-Mixture-Silurian, and it isn’t Cretaceous-Devonian-Permian-Cambrian. Ken Ham, the president of Answers in Genesis, likes to say, “If there really was a global Flood, you would expect to find billions of dead things buried in rock layers laid down by water all over the earth … which is exactly what you do find!”  No, if the sedimentary rock record were a product of a single giant flood, I would expect to find a giant mess. I would not expect to find Cambrian-Ordovician-Silurian-Devonian…

A further problem with the ecological zonation models is that there would have had to have been plenty of critters still alive (and thriving) most of the way through the Flood. For example, think about all of the organisms of the Mesozoic Era (Triassic, Jurassic, Cretaceous). This includes not only the dinosaurs, but a host of mammals, birds, plants, and marine organisms, such as ammonites. Many of these organisms are unique to the Mesozoic, and even unique to subdivisions of the individual periods. Where were they all during the massive catastrophe that deposited the rocks of the Paleozoic? Vast areas of Mesozoic rocks are underlain by Paleozoic rocks. Were they huddled together on islands that had escaped earlier flooding? Were they floating around on mats of vegetation? Both of these proposals have very serious problems, but they are what the Flood geologists seem to be clinging to.

I’m barely getting started, and just scratching the surface. But I need to get back to Dr. Wile’s objection: that grass in the Cretaceous and Coelacanths in the Holocene are enough to discredit the whole thing. Do they? If anything, they discredit geologists and paleontologists who should have been a little more cautious in their statements.

The discovery of grass in dinosaur dung isn’t that big of a change. Paleobotanists had been saying that grass appeared sometime in the Paleocene or early Eocene (perhaps around 55 million years ago), and now we know that there was at least some grass around in the very late Cretaceous (a little over 65 million years ago). In any case, it appears that grasses were probably a minor constituent of the Mesozoic fauna. Perhaps I’m wrong on this. I don’t think any actual fossils of Cretaceous grass leaves have been found. In regards to the Coelacanth, which was once thought to have gone extinct in the Cretaceous but then discovered alive in the Indian Ocean, I think we should expect this sort of thing from time to time. There are fossils that, as far as we know, only lived in the Tithonian age of the Jurassic. Do we know everything? We should expect that for at least some of our index fossils (those fossils that are supposed to tell us the age of the rock in a very narrow range) that some survived somewhere and could even still be alive today.

These are little things. Grass appeared a bit earlier than we knew. Coelacanths survived throughout the Tertiary without leaving any fossils, but they are alive today. The plain and simple fact is that the geologic column exists. What the young-Earth creationists would need to find in order to overturn the well-established and well-justified concept of the geologic column is something like a mastodon in Devonian sediments, or an ostrich in the Ordovician. Until then, I’ll accept Cambrian-Ordovician-Silurian-Devonian… as an observation that is in need of an explanation.

Grace and Peace

As an old-Earth creationist
I believe that the universe was created by the triune God of the Bible
I believe that the Bible does not dictate when this creation took place
I believe in a real Adam
in a real garden

in a real fall into sin

in real consequences for that sin

and in Jesus Christ as the only solution for sin


Dinosaur footprints part 4

About two years ago I wrote three posts on young-Earth creationist (YEC) claims of human footprints being found with dinosaur footprints, and the problems that footprint fossils in general cause for the young-Earth catastrophic “flood geology” model.

Following the wrong footprints

Following more wrong footprints

Dinosaur footprints part 3

To their credit, the major YEC organizations, such as Answers in Genesis and the Institute for Creation Research, haven’t used the “human and dinosaur footprints together” argument for a couple decades, but many smaller YEC organizations do.

Answers in Genesis recently put a new article on its website about the formation of dinosaur footprints: Fossilized Footprints—A Dinosaur Dilemma. The article focuses on dinosaur footprints found in Israel in the Cretaceous Judea Group (A “group” in geology is a sequence of two or more sedimentary rock formations).

The footprints are found in a rock called dolomite. Chemically, dolomite (CaMg(CO3)2) is similar to calcite (CaCO3), which is the primary component of limestone. The author correctly states that dolomite forms only in rather exotic environments, such as desert salt flats and hot springs, or in ocean water of rather unusual chemistry. Dinosaurs could not have survived in large numbers in salt flats, and wouldn’t have been walking through hot springs, so the layers of dolomite must have formed from ocean water. Here’s the explanation in the article:

The pre-Flood ocean floor would have been littered with the remains of mollusk shells, in the form of lime. (Mollusk shells are made out of calcium carbonate, the main ingredient in lime.) When the fountains of the great deep broke up at the start of the Flood, massive earthquakes would have caused the ocean waters to rise and sweep in across the pre-Flood supercontinent, like tsunamis, carrying the lime sediments landwards with them.

The water temperature would have progressively increased as hot volcanic waters were added to the ocean. Also, many volcanic eruptions would have added magnesium to the lime-rich Flood waters. This combination of hot water, lime, and magnesium would produce the layers of dolomite. Thus, catastrophic plate tectonics can explain the increase in Flood water temperatures, the inundation of the continents, and the formation of enormous amounts of “marine” carbonate sediments on the continents.

As all of this gets washed up onto the continents, some dinosaurs who have survived the previous parts of the global catastrophe manage to walk around on the newly deposited dolomitic mud.

There are two major problems with this, in addition to the numerous problems with fossil footprints and “flood geology” I have outlined elsewhere.

  1. Most dolomite in the geologic record is not what we call primary dolomite, that is, dolomite that was formed directly from water solutions. Instead, most dolomite is secondary, formed by the conversion of limestone that was formed in a wide variety of environments. Magnesium-carrying fluids move through pores in the limestone, and react to change the calcite to dolomite. Multiple lines of evidence point to this: obvious recrystallization of calcite to dolomite (the two minerals have different internal atomic structures), studies of strontium isotopes in the minerals, and studies of tiny inclusions of fluids trapped in mineral grains. A quick search on the internet for “Judea group dolomite” brings up articles that discuss all of these as having occurred in the rocks in Israel in which these dinosaur footprints were found. The sediments were composed of lime (calcite) mud when deposited, not dolomitic mud.
  2. The scenario where volcanoes added heat and magnesium to ocean water as the flood progressed doesn’t work either. First of all, seawater is considerably richer in magnesium than in calcium to start with (though I suppose a YEC scientist might argue that in might not have been so before the flood). Basaltic magma (which must be what is being considered in this model, since the seafloor is made of basalt) is rich in both magnesium and calcium, so I don’t see how this would make the ocean into a dolomite-producing brew. Second, the ratio of dolomite to limestone decreases as one goes up the geologic column. If this YEC scenario were correct, the amount of dolomite should increase as the flood progressed.

I outlined the general problems with the “dinosaur footprints formed by the flood” hypothesis in Dinosaur footprints part 3, where I focused on dinosaur footprints in Jurassic and Cretaceous rocks at Dinosaur Ridge west of Denver:

Here’s what would have had to have happened:

  1. The flood covers all the Earth, eroding the continents down to their roots. Most erosion, according to this model, would have had to have happened early in the flood.
  2. At this point, the world-wide ocean was a slurry of water, sediments, and fossils.
  3. Deposition of thousands of feet of sediments, representing Proterozoic through Triassic rocks.
  4. Deposition of some Jurassic sediments. Then some dinosaurs go walking around. Then some more deposition. Then some more dinosaurs–a bunch this time–go wandering around. Then some more deposition of sediments. Then more dinosaurs trotting along the beach. Then more sediments. Wait, how did these dinosaurs all survive the previous part of the Flood?
  5. Deposition of thousands of feet of sediments on top of all of this.
  6. Lithification of the sediments (changing from soft sediments to solid sedimentary rocks).
  7. Uplift of the Rocky Mountains, tilting up these layers to a steep angle (they aren’t horizontal anymore).
  8. Erosion to expose the rocks.

I know that the author of the article read my Dinosaur footprints part 3 post, as it was referenced in the footnotes.  This current AiG article did not adequately address objections such as mine, and its “dinosaurs could not have made footprints in dolomite” approach is a failure.

I write this with love and respect for YEC advocates. They love the Word of God, as do I, and share the desire to see people pointed to Christ. However, I don’t think that the whole YEC flood geology hypothesis works—nor is it Biblically necessary—and for many people it drives them away from Christianity rather than pointing them to Christ and his gospel.

Grace and Peace

Six bad arguments from Answers in Genesis (Part 2)

This is part two of a six-part series examining supposed evidences for a global flood that have recently appeared on the Answers in Genesis web site.
The people at AiG are my brothers and sisters in Christ, and I share their love for the Lord Jesus Christ, their respect for the Bible as the Word of God, and their desire to see people come to faith in Christ. However, I view their arguments for a young Earth and geological catastrophism as unnecessary Biblically, bad apologetics, and a serious obstacle to the evangelism of scientists.
Unfortunately, few people in our churches or Christian education system have the geological background to critically analyze these arguments. The result is that people read articles like these from AiG, find them to be rather impressive, and believe that these present sound arguments in defense of the Bible. The opposite, however, is true. A vast majority of Christian geologists find the arguments for a young Earth and the geologic work of the Flood to be untenable. It is my strong opinion that the young-Earth arguments of organizations like AiG have no place in our churches and Christian education system.
Part one examined the young-Earth creationist (YEC) argument that fossils at high elevations are proof of a global flood.

Flood evidence number two” from Andrew Snelling of Answers in Genesis is called “The World’s a Graveyard” and claims that fossil graveyards around the world provide proof for a global flood.

According to Snelling, layers that contain large numbers of fossils, or that contain extraordinary preservation, can only be explained by catastrophic processes. Some of his examples include:

At Florissant, Colorado, a wide variety of insects, freshwater mollusks, fish, birds, and several hundred plant species (including nuts and blossoms) are buried together. Bees and birds have to be buried rapidly in order to be so well preserved.

Alligator, fish (including sunfish, deep sea bass, chubs, pickerel, herring, and garpike 3–7 feet [1–2 m] long), birds, turtles, mammals, mollusks, crustaceans, many varieties of insects, and palm leaves (7–9 feet [2–2.5 m] long) were buried together in the vast Green River Formation of Wyoming.

Notice in many of these examples how marine and land-dwelling creatures are found buried together. How could this have happened unless the ocean waters rose and swept over the continents in a global, catastrophic Flood?

According to Snelling, catastrophic flooding is the only way to form layers with large numbers of fossils, or to preserve soft parts.

Here are some basic problems with Snelling’s argument:

  • The first paragraph refers to the Florissant fossil beds in Colorado. The standard geological explanation of the Florissant Formation is that volcanic flows (lahars) blocked a valley, forming a lake. This lake gradually filled with mud and volcanic ash, which trapped fossils from the surrounding community of organisms.
    Fossil wasp from the Florissant Formation (credit: xxx)
    Fossil wasp from the Florissant Formation (credit: National Park Service)
    • Rather than providing for exquisite preservation, a catastrophic slurry such as Snelling proposes would have ground fragile objects such as leaves, flowers, and insects to microscopic fragments.
    • Rapid deposition could be one way to preserve soft parts as fossils, but it is not the only way. Rapid deposition can be a means of preserving delicate parts in a relatively still environment, but is unlikely to do so in a truly catastrophic environment. Anything that keeps decomposers (such as bacteria) away from soft parts will make preservation possible. This could be thin layers of diatoms, as appears to be the case at Florissant, or anoxic (zero oxygen) or toxic bottom conditions, which are well-documented in the natural world today. For example, deep waters in the Black Sea are anoxic, so there is little decomposition of organisms that sink to the bottom.
    • The fossils at Florissant form a coherent ecological package; a group of organisms that would naturally live together in the same ecosystem. If deposited during the Flood, these would have had to been ripped up (gently) by the beginning phases of the Flood, somehow kept together as a unit without mixing with other fossil assemblages while other sediments and volcanic deposits were being formed, and then gently deposited in a 1 x 15 mile area.
    • Having the Florissant Formation created as a post-Flood deposit, as some young-Earth creationists propose, doesn’t help at all. In this case, the entire ecosystem would have had to been established in a short time after the Flood while intense volcanism occurred nearby, and then be washed down into a valley without shredding leaves or breaking wings off of insects. Either way, it just doesn’t work.
  • The second paragraph refers to the Green River Formation of Wyoming. What Snelling doesn’t let you know is that the fossils of the Green River Formation also represent a coherent ecological package.
    • The fossils do not form a random mixture of alligators, sunfish, bass, chubs, pickerel, herring, garpike, birds, turtles, mammals, mollusks, crustaceans, insects, and palm leaves as Snelling implies. These fossils, and many more, are all present, but in a very systematic arrangement that reflects a complete lacustrine (lake) ecosystem. Open water organisms are found in the central part of the basin, shoreline marsh organisms are found towards the edges of the basin.
    • It doesn’t help to suggest that the Green River Formation was formed in a lake after the Flood. For this to happen, the lake would have had to form, a complete ecosystem would have had to form (which doesn’t happen overnight), and then somehow rapid sedimentation would have had to occur with fine-grained lake sediments. By the Answers in Genesis Flood model, this all happened sometime in the time after about 2300 BC. Too many events in too little time.
  • Snelling says, “Notice in many of these examples how marine and land-dwelling creatures are found buried together.”
    • Not a single example given by Snelling is of a unit that has marine and non-marine organisms mixed together. I don’t have the slightest idea what he is getting at.

Answers in Genesis has a deep and wide influence in Evangelical churches and schools. Many look at this as a positive thing. I look at it as an apologetics disaster.

An excellent resource for anyone who wants to dig further is The Bible, Rocks and Time by Christian geologists Davis Young and Ralph Stearley (Chapter 9 Fossil Graveyards: A Rumble in the Jumble).

With love for the body of Christ.