The Creationist Bedding Blunder
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[edit] Introduction
There is a widespread belief amongst creationists that geologists claim that the beds visible in sedimentary rocks were laid down at intervals of millions of years.
No geologist believes this, as it is not true. Any geologist could demonstrate that it is not true, and indeed it is so manifestly untrue that even creationists are capable of demonstrating its untruth.
By asserting, then, that it is the belief of geologists, they can provide a wonderful demonstration that what they think geologists claim is wrong. The reader familiar with creationist nonsense will recognize this as a classic example of a straw-man argument: one formulated, not against what scientists think, but against what creationists would like to think that geologists think.
There is no formal name for this particular creationist error: we have ventured to christen it the bedding blunder.
We should note that not all creationists who commit the bedding blunder explicitly state that this is what they think that geologists think. But, as we shall see, they often put up arguments, supposedly against geology, which would only be arguments against geology if geologists did think that the formation of consecutive beds was separated by million-year intervals.
[edit] What geologists actually think
Geologists attribute the beds in sedimentary rocks to the same processes that we can see today laying down beds in sediment: sedimentary rocks, they claim, are merely lithified examples of exactly the same processes.
Many of these processes exhibit annual variation which produces one bed per year: for example, when a river deposits sediment, it will deposit heavier sediment when it has high energy, in the rainy season, and, in the same place, deposit lighter sediment when it has lower energy in the dry season. Similarly the varves formed in proglacial lakes reflect an annual cycle: in summer, outwash from melting glaciers carries relatively coarse sediment into the lake; in winter, the lake freezes over and the stilling of the water allows fine particles of clay and organic matter to settle, producing the characteristic pattern of bedding found in such lakes.
Other processes are intermittent. For example, turbidites are laid down by turbidity currents that lay down first coarser, than finer sediment. These currents are triggered by submarine earthquakes, which occur with much greater frequency than one every million years or so. In the same way, when a volcano erupts, the coarser volcanic ash settles out of the air before the finer volcanic ash, producing bedding: the same volcano can erupt in this way several times a week: millions of years do not come into it.
Other processes are more or less continuous: for example, the sets of cross-beds in desert sands are produced by tiny avalanches of sand-grains down the downwind faces of sand-dunes, and so sets of cross-beds will be deposited continuously as sand-dunes are driven by the wind across the face of the desert.
[edit] Origins of the blunder
We have not been able to trace the creationist error back to its originator.
However, we believe that we have identified, if not the originator, than at least the nature of the mental processes that led creationists to make so grotesque a blunder. As an example of creationist thought, let us take Mr Ian Taylor, of CreationMoments.com, who writes:
- Everyone today has been taught that each layer of rock typically seen in road- cuttings, was laid down as sediment, one upon another, from a sequential series of floods in the past. We are told that after the return of the floodwaters [...] millions of years passed by until a similar flood occurred and repeated the process to form the next layer of sedimentary rock. [1]
Now, it should be obvious to any student of geology what has happened here: creationists have confused the depositional processes to which geologists attribute bedding with the regressions and transgressions of the sea to which geologists attribute unconformities.
Insofar as creationists think about what they're saying at all, creationists think that geologists think that all bedding planes are unconformities. Though of course creationists would not phrase it that way, since anyone who knew the definitions of the words "bedding plane" and "unconformity" would not commit the bedding blunder in the first place.
[edit] Creationist applications of the bedding blunder
There are numerous facts which show that consecutive beds in sedimentary rock are not separated in their formation by millions of years. So, once creationists have decided to pretend that this is what geologists think, they can produce any quantity of evidence to show that geologists would be wrong in thinking this. For example:
- Creationists are fond of talking about what they call polystrate fossils: that is, fossils such as tree-stumps that project through several layers of rock. This would be incomprehinsible in terms of beds being laid down at million-year intervals: it is perfectly comprehensible in terms of what geologists actually claim about bedding in sedimentary rocks.
- In the same way, creationists claim any evidence of an organism being rapidly buried as evidence against geology. And it would be --- if geologists claimed that deposition of an inch or so of sediment took "millions and millions of years".
- The fact that beds with different lithologies grade into one another --- for example, shale grading into sandstone --- would also be incomprehensible if there was a million year interval between the deposition of beds. It is perfectly comprehensible in terms of a continuous uninterrupted process which, as a result of varying in intensity, also varies in the sort of sediment it will deposit in a given spot.
- Creationists are also fond of pointing to the rapidly deposited beds of volcanic ash formed by consecutive volcanic eruptions as evidence against geology. Again, this would be spledid evidence against geology if it was a doctrine of geology that an interval of millions of years must necessarily intervene between the formation of such beds. But in fact, geologists know perfectly well how they form.
These examples point up a curious yet ubiquitous feature of creationist thinking. For it is obvious that all of these counterexamples to the supposed doctrines of geologists have been supplied to them by --- who else but geologists? It is geologists who observed and reported that beds of different lithologies grade into one another. It is geologists who observed and reported how beds of volcanic ash are deposited. It was geologists who observed and reported the projection of certain fossils through multiple beds of sedimentary rock. And it was geologists who observed and reported the evidence that certain fossils (though by no means all of them) exhibit signs of rapid burial.
A moment's application of common sense would therefore suggest to a creationist that geologists cannot in fact uphold the doctrine that creationists attribute to them. But common sense, as the reader may be aware, is a commodity in short supply in the creationist movement.
