>It seems to me that one of the most essential
>notions in the study of geology is the claim that
>one can make reliable rock/formation correlation's
>over great enough distances and with great enough
>frequency to be able to make sense out of the
>geologic pile over large distances. Now I realize
>that one need only step outside to be convinced that
>one can make correlations over small distances.
I would suggest one of two sources for this. First is Derek Ager's The
Nature of the Stratigraphical Record and an article I published in the
Creation Research Society Quarterly, Morton, G. R. (1984). Global,
Continental, and Regional Sedimentation Systems and Their Implications
Creation Research Society Quarterly. 21:23-33.
Both of these show how long distance correlation works. Take the Redwall
Limestone of the Grand Canyon. It is eroded (karsted) at the top, has zones
in which dead crinoids make up the majority of the rock fabric, and contains
a brachiopod, Productus giganteus and fragments of chert. Most often the
Limestone is overlain by redbeds, whose red color leaches out of the red
rocks and stains the upper part of the limestone. This is why the Redwall
limestone at the Grand Canyon gets its name. These traits can be traced
north into Colorado, where the equivalent limestone is called the Leadville,
Further north it is the Madisson Formation, in Canada, it is the Rundle and
further north in Alaska it is called the Lisburne limestone. In the
Midcontinent region it is called the Keokuk and Burlington formations.
While at the Grand Canyon, there is no underlying black shale, quite often
there is an underlying black shale. There one in Alaska, throughout the
midcontinent (called the Chattanooga Shale) through Oklahomas and into the
eastern US where the limestone is called the Ft. Payne Chert and the
underlying black shale is the Chattanooga.
In Belgium 24 iguanodon skeletons were removed from the red sediments
infilling a karst (erosion) in a crinoidal limestone. Such limestones are
also found throughout Russia and Central Asia and into Kashmir.
This is how long distance correlation works. One doesn't have to have the
fossils to achieve such correlation, but if you consider the fossils as
unique sedimentary particles, then you can add certainty to the correlation.
>I can accept that to some extent geology is a craft,
>much as pouring cement is a craft. I would not
>necessarily expect to find a "cement 401" textbook
>examining the foundation principles of pouring
>cement. However, many geologists give the
>impression that theirs is also an academic discipline.
Thanks for the complement to us geoscientists. :-(
>They seem to give the impression that the rest of
>society should be convinced of the truth of their
>conclusions. I find many texts giving a "description"
>of the principles of geology. I have never found
>a text giving a rationally convincing quantitative
>"defense" of the principles of geology.
Exactly what textbooks have you read? Can you name them for me, perhaps I
can point you to other places.
>
>I realize that the rock pile we all live on is
>enormously complex and a complete description
>is impossible in a textbook. What would I expect
>to see in such a foundations text? First, I would
>at least expect to see some sort of index or quantity
>defined for a formation that is a measure of the
>distance over which points in the formation can be
>reliably correlated using only those properties of
>the rock unit that are present everywhere in it,
>such as color, chemical composition, texture etc.
>I would expect to see example scatter plots each
>for a specific location, on which each formation
>present at that locality is represented by a point
>on the plot - the axes of the plot would be the
>formation thickness versus this correlation
>distance index.
Does the above brief description fit your bill?
I would expect to be informed
>about where I could go to find such scatter plots
>for most any locality I was interested in. I would
>expect also to see some index developed indicating
>the quality of the correlations represented by each
>such scatter plot. I would expect to see various
>distributions showing the variation pattern of such
>a quality index over the earth. I don't claim to have
>the best way figured out to do this but that is not
>the task of the student. I would expect to see some
>scheme showing this information, though. Again, I
>am amazed to not be able to find such a text from
>an academic community many of whom seem to
>think that their conclusions should be believed by
>the rest of society.
>
>A second group of notions I would expect to see
>developed in such a foundations text would be
>notions relating fossil correlation and/or other
>correlations based on potentially sparse data points,
>to the above types of correlation indices. I would
>expect to see indices developed relating fossil
>densities to the above homogeneous properties
>correlation distance measures. Again, I would
>expect to see scatter plots and distributions showing
>the global variation in such fossil correlation quality.
In other words, you are expecting a statistics book. Why should geology,
which settled on its foundations a century ago, have to repeat this because
Christians won't go on field trips to actually look at the rocks. Have you
ever been on a geologic field trip over a large subregional area?
>Let me go a little further to put my question in
>a less abstract setting. I have no doubt that
>rock correlations of various types which are
>of great practical value, can be made with
>considerable confidence. It seems clear that
>this can be done well especially within a basin
>or other such region, in the case of some of the
>formations. For example, I live near the "hogback"
>that runs along the mountains west of Denver CO.
>It is very easy to correlate the Dakota formation
>or the Fountain formation along that hogback
>over great distances. The Dakota forms the ridge
>of the hogback and the Fountain gives Red Rocks,
>Roxborough and Garden of the Gods Parks their
>distinctive formations. However, beneath the Dakota
>and above the Fountain are the Morrison and other
>formations. I have a good deal of difficulty in visibly
>correlating the Morrison versus other formations
>beneath it, between roadcuts that are only a couple
>of miles apart. I am not claiming that there is no way
>of reliably making such correlation by means other
>than what is blatantly visible, I am suggesting that
>after reading such a foundations text, I should
>know how to go about firmly establishing the
>degree of confidence in such a correlation.
Go to the local college and take a field mapping course. It takes about 6
weeks in a summer and is great fun.
glenn
Adam, Apes, and Anthropology: Finding the Soul of Fossil Man
and
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm