The Geological Column: Putting the ‘Jurassic’ in Jurassic Park

The geological column… it’s a topic that must be understood if we want to discuss fossil evidence for evolution and the evolutionary trees that are described by evolutionary science.  It is the basis for how contemporary science dates rocks and fossils and decides where samples are placed chronologically in the fossil record.

The geological column is a chronological representation of the Earth’s history.  By examining and hypothesizing about layers of geological deposits on the Earth’s surface, scientists have come up with a hypothetical classification of 10 layers of rock that are considered to be deposited one after the other in chronological order throughout the world.  ’Jurassic’ is the name of one of those layers in the geological column that represents a period of time when dinosaurs were plentiful.

The top geological layer is considered the youngest and the bottom geological layer considered to be the oldest rock. The geological column is the basis for how paleontologists and geologists date rocks and the fossils found within them.  It is a hypothetical classification that was based on rock outcroppings in areas of Europe and applied as a classification system to classify rocks and fossils around the world.

Geological Column: Youngest to Oldest

Below are the names of the time periods from the oldest (deepest) layers of the geological column to the youngest (topmost) layers of the geological column. They are listed in chronological order according to the current understanding of most geologists.

1: Cambrian  2: Ordovician  3: Silurian  4: Devonian  5: Carboniferous  6: Permian  7: Triassic  8: Jurassic  9: Cretaceous  10: Tertiary (Paleogene and Neogene)

Problems with Concept of The Geological Column:

Geological Column Thickness

There are some places where all hypothetical rock layers in the column can be seen together.  However, the thickness at the best of these areas is about 16 miles, or 25 km thick and the average worldwide thickness is only one mile. [Morris and Parker]   According to the dates associated with this hypothesis, the thickness of the standard geological column should be about 100 miles, or 160 km thick, up to 200 miles or 230 km [Morris and Parker]…give or take.

The vast thickness would be due to the hypothesized times involved with the laying down of sediment through earth’s history. The 16 miles that is actually observed out of what should be 100 to 200 miles is very thin compared to what would be expected with a complete geological column.

Geological Column Overlapping Fossil Ranges

There are overlapping fossil ranges trough different periods of the geological column.  ‘Index Fossils’ are those found only in a certain range in the column.  T-Rex and Velociraptor fossils may be found in the Jurassic period, for example. [Stephen Spielberg :)]  They would be used to help define the Jurassic period when examining rock layers.  If fossil ‘A’ is typically found in the Jurassic rocks, and fossil ‘A’ is found in a particular location, then the level in the geologic column where it is found will be classified as Jurassic.

The problem lies in the fact that index fossils are continuously discovered in other layers of the geological column.  They overlap with other index fossils from other levels in the column, which widens their ranges.  As this happens more often, many former index fossils have to be discarded as a means for classification of the rock layers in order to maintain the integrity of the geological column.

The other possibility is that the  rock layers don’t actually represent periods of time and were not laid down chronologically in the first place.

Geological Column Side-By-Side Fossil Classifications

Fossils classified as being found in older and younger rock layers in textbooks charts on the geological columnn are rarely found in side-by-side layers when actually on location.  For example, Triassic is older than Jurassic.  Fossil ‘T’ found in the Triassic layer is therefore considered older than fossil ‘J’ found in the Jurassic layer.  The problem is that in most cases fossil T is found in one place in the world and fossil J is found in another location altogether.  So T and J are usually found in places where the Triassic and Jurassic layers do not actually exist simultaneously.  This makes the chronological relationship between the layers and fossils murky at best.

Complete Geological Column

There are a number of places where the complete geological column can be said to exist, though it is much thinner than would be considered ‘complete’.  These areas make up only about 1% of the earth’s crust. [Woodmorappe]  We’ve already discussed the issues with the thickness of the ‘complete’ areas of the geological column, but these numbers show that scarcity is also an issue.  Why is the 1% of the earth where the ‘complete’ geological column exists considered significant enough to be used as a proof for the geologic column?  In 99% of places around the world it does not follow the completed pattern.

Defense of the Geological Column

Proponents of the geological column defend the lack of completeness and thickness of the geological column by blaming the missing geological periods in sample areas around the world mainly on two things:

1. Times of non-deposition of sediments.
2. Erosion.

The idea is that the missing periods would be expected because all the areas of the earth would not be depositing at the same time, or were eroded away.  This sounds reasonable, but if this is the case, over the last several million years, how could anyone know when and where different areas were depositing sediment or eroding entire layers?  Without knowing this, how could we develop a complete picture of the geological column?

Without the complete geological column as a tool to measure which areas are incomplete…there is no way to tell which areas are ‘non-depositional’ and which areas have eroded.  An ‘a priori’ assumption that the current geological column structure is accurate is necessary before you can even evaluate whether there are times of no deposits or excessive erosion.  According to Woodmorappe, there is little to no outside evidence that the non-depositional or erosive stages of the geological column occurred.

This takes a process that hypothetically could have removed layers in the geological column, then uses the layers that are missing as proof that the process actually did what was hypothesized.

It’s like saying that 1% of Canadians are millionaires, so it must be the way things should be everywhere in Canada (Geological Column).  The lack of a million dollars in 99% of the population must be because someone stole their money (Non-deposits and erosion).  The ‘proof’ that someone stole the money is that it is missing (Lack of complete geological column).

Not a good explanation for my lack of a million dollars…and not a good explanation for lack of certain layers in the geological column.  Not to say that the geological column idea is a completely illogical hypothesis, just that it may be a hypothesis without good evidence.

Rocks Dating Fossils and Fossils Dating Rocks

There are radiometric dating methods that attempt to get accurate dates for rocks and fossils, but they are difficult to access at times and they can give different results for different samples of the same specimen.

They also make assumptions:

1. They assume a known starting amount of the element being measured.
2. That there were no outside factors affecting that amount other than it’s known rate of degradation throughout history.

Most labs require a palaeontologist’s date estimate based on where the fossil or rock was found in the geological column.

In practice much of the dating is done by dating the rock according to what fossils were found there…or dating the fossils by the rock layer in which they were found.  The problem inherent in this system is self-evident:  How can you use the rocks to date the fossils and at the same time use the same fossils to date the rocks?  You would first have to be 100% sure the geological column is accurate with precisely known dates for each layer and then all the fossils found in each layer would have to be 100% exclusive to that layer.  Neither of these things are close to certain…or even measurable with any kind of certainty.

OK, that’s enough rock and bone talk.  I apologize for another long winded article! It’s tough to make this stuff any shorter and I’m still not doing a real thorough job.  Next time we’ll discuss transitional fossils…transitions between different species.  There should be lots of them to discuss if life evolved through evolutionary transitions…

Please leave a comment.  I hope to see you back for the next post.  If you haven’t signed up for email notifications, you can fill out the form below.  It will also give you a report on historical evidence for the Resurrection of Christ.  You will likely find that more interesting than talking about rocks!

References:

[Morris and Parker]  Hayward, A., Creation and Evolution: The Facts and Fallacies, Triangle, London, pp. 117–119, 1985.
[Woodmorappe] The Geological Column: Does It Exist? Creation Ex Nihilo Technical Journal 13(2): 77-82, 1999

Tagged as: dating rocks, fossils, geologic column, geological column