To: All Msg #136, Jul1393 05:26PM Subject: Geologic column (was: +quot;Re: Creation and Ev
From: Chris Stassen
To: All Msg #136, Jul-13-93 05:26PM
Subject: Geologic column (was: "Re: Creation and Evolution")
Organization: The Lion's Den - Newark, Ohio
From: email@example.com (Chris Stassen)
Lionel Tun writes:
> Such as: fossils are dated by observing what rock strata they
> appear in. Rocks are dated by what fossils appear in the strata
> they come from.
Lionel has made this claim before, and several people have in the past
given definitive refutations of it. However, this claim appears quite
frequently here and probably deserves a FAQ.
Here's some old material which might be good for a starting point:
Included article <1992Apr23.firstname.lastname@example.org>:
Perhaps this article can "evolve" into a FAQ someday (any professional
geologists out there willing to help out?). The topics that I plan to
1. How the column was originally assembled
2. Later independent verification methods
3. A few common creationist objections
1. How the column was originally assembled.
It is important to note that the column was not assembled originally as
a series of events or formations spaced by determinate amounts of time
(i.e. an absolute sequence). Rather, it was assembled as a relative
sequence (i.e., X before Y before Z), without any solid idea of the
timing of these events, or what if anything was missing from between
them. The key role in this development was played by the Principle
of Superposition (younger sediments overlie older ones).
The Phanerozoic periods were first identified in Europe. In fact, one
could take a stroll and encounter formations representing all of the
periods, overlain in order (this is more convenient than digging
thousands of feet to get to them, but one could do that as well). The
following cross-section of Europe represents a straight-line route which
starts in Northwestern Wales, and ends at London (curvature of the earth
ignored; vertical scale greatly exaggerated; diagram slightly
NW Wales London
B = basement igneous D = Devonian K = Cretaceous
c = Cambrian i = Carboniferous p = Paleogene
O = Ordovician T = Triassic
s = Silurian j = Jurassic
This was derived from figures in:
_Evolution of the Earth_, Dott & Batten, 1988 (4th edition), p. 54
_Historical Geology_, Carl O. Dunbar, 1949, p. 182
(I will send photocopies of the figures to anyone who asks me via Email.)
This is basically how the column was originally identified and assembled;
all of the periods are found in order where geology was born. The use
of index fossils and such helped to identify the same formations in the
same order *elsewhere*, which further strengthens the original order.
For further information:
_A Trip Through Time_, Cooper, Miller, and Patterson; Columbus, Merrill
Publishing Company, 1990 (second edition). Chapter 6 (pp. 154-186)
_Great Geological Controversies_, A. Hallam; New York, Oxford University
Press, 1989 (second edition). Chapters 1-3 (pp. 1-86)
2. Later independent verification methods
More important than the method used to originally assemble the column
are methods invented since which can be used to test the ordering.
While "superposition" (without assumption of time intervals) is not very
controversial, it is also not surprising that the column is in agreement
with it -- for that is how it was put together. However, an ordering
method which wasn't dreamed of when the column was originally assembled
is the best sort of verification that one could hope to get.
A) Radiometric dating
Radiometric dating was conceived in the first half of this century.
While it does have limitations and requires certain historical
assumptions be valid, radiometric dating methods produce results in
concordance with position in the geologic column about 95% of the
time. Provided that there are reasonable explanations for the 5%
anomalous cases, this is an independent test against the ordering
derived by stratigraphy.
For example, K-Ar dating was tested against the North American Land
Mammal ages of the Cenozoic, whose ordering was originally derived
Stratigraphic K-Ar Date # Samples
Position Name of Age (x10^6yr) Dated
======== ============ ========= ==========
1 Irvingtonian 1.36 1
2 Blancan 1.5 - 3.5 7
3 Hemphillian 4.1 -10.0 8
4 Claredonian 8.9 -11.7 16
5 Barstovian 12.3-15.6 9
6 Hemingfordian 17.1 1
7 Arikareean 21.3-25.6 4
8 Orellian --- 0
9 Chadronian 31.6-37.5 9
10 Duchesnean 37.5 3
11 Uintan 42.7-45.0 2
12 Bridgerian 45.4-49.0 2
13 Wasatchian 49.2 1
14 Puercan 64.8 1
(Table from the Dalrymple paper, listed in references below, which
is available from Wesley Elsberry for postage cost.)
Clearly, in this example, the ordering derived from radiometric
dating and the ordering derived from stratigraphic position are
The primary reasons why the ordering of the geologic column is accepted
as originally assembled are: 1) consistently finding the same
formations in the same order all over the world (though there are many
places where some are missing, the relative position is quite
dependable); and 2) independent confirmation of that ordering from
radiometric dating. However, there are several other minor independent
means by which we could order the column. I will explain one example:
B) Astronomical dating
Astronomers propose that tidal forces have been slowing the earth's
rotation at a miniscule (and probably variable) rate. This means that
the number of days in a year has slowly been decreasing over time.
I have somewhere (but I couldn't find it this weekend) a study on the
number of daily growth layers per year in various fossilized creatures
(corals and stromatolites, mostly). These values, used as an ordering
method (higher number of days per year = older) provides the same
ordering as both stratigraphy and radiometric dating.
An article covering only corals is available as Scientific American
Offprint #871 (Runcorn, R. K., 1966, "Corals as paleontologic clocks").
_Principles of Isotope Geology_, Gunter Faure; New York, John Wiley and
Sons, 1986 (second edition). A technical handbook/textbook.
_USGS Open-File Report #86-110_, G. Brent Dalrymple; United States
Geological Survey, 1986. A response to creationist criticisms on
_Geologic Time_, D. L. Eicher; New Jersey, Prentice-Hall, 1976.
Details several dating methods (including "coral clocks").
3. A few common creationist objections
Perhaps Jim will aid me in filling out this list. However, I'll pick a
few examples from the literature that I have for now.
A) Circular reasoning. Creationists claim that the fossil record is
ordered by the assumption that life evolved in a certain manner, and
therefore the appearance of evolution in the fossil record is not
surprising (e.g., Morris & Parker, _What is Creation Science?_, pp.
The geologic column was first assembled and ordered by scientists who
did not accept evolution. It therefore cannot be the product of the
assumption of evolution in any manner.
The quotations which creationists present, in regard to possible
circularity, involve the use of so-called "index fossils." These
fossils were in use by geologists long before evolution was accepted.
Rather than being any presumed "evolutionary age", they are merely
fossils which are only found in a narrow range in the column. When
found in a formation whose age is unknown, that formation is assumed to
hold the same position in the column as other formations that have
identical fossil content.
If the fossil record looked like the ICR wants you to believe, the use
of index fossils never would have occurred. Geologists never would have
found any fossils that are restricted to only a narrow range of strata.
Even the creationists will admit that this isn't the case, on occasion:
"Many scientists, both creationist and evolutionist, would
agree that there is a distinct order to the geologic strata,
with characteristic fossils occupying the different layers.
It is important to remember that the 'geological column'
was worked out in the early 1800s, before Darwin published
the *Origin of Species*, by men who almost universally
believed in creation."
[Sylvia Baker, _Evolution: Bone of Contention_, p. 15]
"Scientifically, the major challenge facing Flood geologists
is the regularity of the fossil record. If the flood and its
aftermath were responsible for the deposition of the fossil
record, would not plants and animals be all jumbled together?
Sometimes fossils are jumbled together .... Still,
the majority of fossils are associated consistently with
identifiable systems such as the Cambrian, Ordovician, etc."
[G. Parker, _The Fossil Record in Christian Perspective_, p. 77
in Wonderly, _Neglect of Geologic Data_, p. 59]
Note that, to be fair to Parker, he goes on to claim that "ecological
zonation" can explain the ordering. To be unfair to Parker, Wonderly
goes on to explain why that's a ridiculous idea.
C) Radiometric dating methods don't always work. Creationists will
point to lists of anomalous results as if they invalidate the
The problem for scientists is that they must explain why radiometric
dating methods fail to produce concordant values about 5% of the time.
Since the requirements for a valid date are usually stated up front,
what is involved is usually the violation of one of the requirements.
It is quite common for scientists to be able to explain the exact
reasons which yielded the invalid date. For example, "Big Daddy?"
(Jack Chick) claims that a living mollusc dated by Carbon 14 to about
three thousand years in age. The anomaly is explained by the fact that
molluscs derive carbon from sources other than the atmosphere (e.g.,
weathered carbonate rocks) and therefore invalidate the initial
conditions for "carbon dating."
The problem for creationists is that they must explain why radiometric
dating methods produce concordant values 95% of the time. This sort of
consistent performance cannot be explained as random luck. A process
which yields concordant (but misleading) results must be demonstrated.
I suppose that if I gave a creationist five alarm clocks, each of which
worked 95% of the time. When they all said it was time for him to get
ready for work, I wonder if they would be ignored? There are plenty
of cases where multiple radiometric dating methods agree on the age
for a given object.
_Neglect of Geologic Data: Sedimentary Strata Compared with Young-Earth
Creationist Writings_, Daniel E. Wonderly; Pennsylvania, IBRI, 1987.
An old-earth creationist blasts young-earth creationists' comments on
the geologic column. Available for $8.45 (postage and handling
included) from IBRI / P.O. Box 423 / Hatfield, PA 19440. Should be
required reading for any young-earth creationist.
Chris Stassen (614) 366-9628 email@example.com
E-Mail Fredric L. Rice / The Skeptic Tank