RE: [asa] geological dating

  -----Original Message-----
  From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu]On
Behalf Of Don Winterstein
  Sent: Saturday, October 17, 2009 2:40 AM
  To: asa
  Subject: Re: [asa] geological dating

  Evolution doesn't necessarily imply common descent. If you have organisms
coming into and passing out of existence in the order we observe, you have
evolution, whether or not it all happened by special creation.
No. If it is by special creation, it is not Evolution as in the ToE. Are you
using evolution in the broadest of senses, as in just change of an
assemblage. Then we are talking two different types of evolution.
   No one can say in detail what God's role was in this evolution we know,
and it's possible that he caused much to happen that would not have happened
without his special action. So indeed every organism could be a special
creation in some sense.

Irrelevant.

  [Science cannot legitimately say that the biotic world is not an
infinitude of special creations, but it would be in complete violation of
its methods and principles to say that it is. The role of scientists is to
see how far they can go in explaining things without invoking special
creations and creator(s).]

  In any case the utility of index fossils is evidence for evolution and
would be inconceivable without evolution.

No. If God specially created them in that order, involving no evolution
(think ToE), you wouldn't be able to tell the difference. Even as a
Geologist I can understand that. Kurt Wise, a creationist geologist
understands this as well, and struggles with it. I acknowledges that it
certainly looks like evolution occurred but just won't bring himself to
believe it is real. The index-ness would still be the same.

  The possibility of special creations opens the possibility of kinds of
order that are radically different from the one we observe.

Again, only if God specifically created them in the order that we see. Of
course, the order sure looks as if evolution (common decent) certainly
occurred, of course that is all we Geologists can go on, observations. And
with those observation, we have no scientific reasons to conclude otherwise.
  If the actual order had organisms oscillating between emergence and
extinction, then of course there would likely be no useful index fossils.

Who said anything about "oscillating?" Is that an inherent property of
special creation? The "special creation" I am referring to is not specific
to Flood Geology where index fossils would not exist - Kingina would be
found everywhere. Rather, millions of creation events through Geologic time,
that is espoused by OECs. So if God created Kingina only during the
deposition of the Georgetown Formation, it would only be found in the
Georgetown Formation of the Cretaceous, without any regards to evolution
(ToE) even occurring. This would be a creation the likes that Hugh Ross
promotes, a progressive creationism.

   An oscillating biosphere would constitute a whole other kind of
evolution. The utility of index fossils depends on a particular kind of
evolution, namely, monotonic--the kind we have.

  [It's not obvious--and in fact curious--why an omnipotent, omniscient
creator would choose this monotonic approach out of all available
possibilities.]

  As for age range, index fossils can only indicate an upper limit of age.
It's always possible that index fossils will turn up in formations younger
than the formations where they first appeared, even if their organisms
quickly went extinct: Sedimentary rocks can be "reworked."

Indeed, and the lithology would reflect that. That is irrelevant to my post.

  Trilobites from Cambrian to Permian did not constitute a single index.
There's great variation among the 17000 known species of trilobites--as also
among brachiopods. Not all lived at the same time.

While I did not spell it out, I figured it would have been understood. I
guess I shouldn't have done that. If trilobites are considered as some kind
of index, it would not be a species index, but rather a Class index. That is
all I was saying. As a Class index, the range of the entire Class Trilobita
occurs within the boundaries of C-P, since no observations of a member of
that class has been observed beyond that range...so far. Should any (in situ
or undisturbed) - observations fall outside that range, the index range is
expanded. Again, this has nothing to do with evolution. That's all. This
isn't hard.

Is that any clearer?

  Don

You missed the point of that comment and pretty much my entire post. On some
points you think you are being contrary yet saying the same thing or going
on about irrelevant points. A handy reference to have in your library when
the Treatise on Invertebrate Paleontology is not available is Invertebrate
Fossils - Moore - Lalicker - Fischer -1952.
    ----- Original Message -----
    From: skrogh
    To: asa
    Sent: Wednesday, October 14, 2009 8:21 AM
    Subject: RE: [asa] geological dating

    Sure you would. Even if evolution (common descent) didn't exist, and it
was all individual little creation events that brought the life forms into
being in a certain observed order, it wouldn't change the "index-ness."
This is getting the kart before the horse. Without evolution, you would
still be able to say this. What you wouldn't be able to say is that fossil x
could have developed from a certain lineage. Since index fossils do indeed
exist, it doesn't matter. Index fossils are only reliable in relative dating
until that fossil is found outside it's former range, and only tentative. I
did a study on the very unassuming brachiopod Kingena wacoensis, which was
later named Waconella wacoensis. This brach was only considered an index
fossil because its high reliability in what formation it just happened to be
observed (Georgetown Formation of the Cretaceous) and it has never been
observed outside of this formation. The idea of common descent has no
bearing on it being an index fossil, only that it has never been observed
outside of the Georgetown Formation. If it is observed outside the
formation, the formation wouldn't be expanded to include the fossil, but
rather the age range of the fossil would be expanded to accommodate the new
find and it would simply no longer be considered an index fossil for a
specific formation. It may be considered an index like trilobites which
spans from Cambrian to Permian.

     -----Original Message-----
    From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu]On
Behalf Of Don Winterstein
    Sent: Wednesday, October 14, 2009 9:03 AM
    To: asa
    Subject: Re: [asa] geological dating

      "evolution is not integral to the dating...."

      Index fossils are widely used for relative dating of rocks, so in that
sense evolution is integral to such dating. That is, if you find fossil x,
you know that the formation is no older than the time at which fossil x
first appeared. Without evolution you wouldn't be able to say this.

      Don

        ----- Original Message -----
        From: David Campbell
        To: asa@calvin.edu
        Sent: Tuesday, October 13, 2009 10:08 AM
        Subject: Re: [asa] geological dating

        A couple of minor caveats:

        In addition to 14C, there are some fossils containing radioisotopes
        that can be used for dating. For example, corals often contain
enough
        thorium to date, and various types of replacement may involve
        radioactive elements , e.g., the often uranium-rich dinosaur bones
in
        parts of the western U.S. or glauconitic molds of marine organisms
        (though of course, the date will reflect when the replacement
        occurred, not the original organism, and glauconite has a number of
        issues).

        However, in general an igneous rock is the best for radiometric
        dating. (A metamorphic high-pressure carbon isomorph might do
better
        for some other dating). Obtain dates on several different minerals
        and isotopes from a single rock, and you've got a very
        well-constrained age, with the caveat that a given rock may
        crystallize slowly. A volcanic ash layer associated with fossils is
        thus about the best-case scenario for dating.

        All sorts of long-term trends or variations can provide relative
dates
        and then be calibrated with radiometric dates. These include, among
        others, changes in stable isotope ratios, magnetic reversals,
        Milankovitch cycle-related changes, impact layers, and evolution.
The
        evolution is not integral to the dating; it just is the explanation
        for why you see change in organisms over time and can therefore be
        confident that, e.g., a layer with Chesapecten jeffersonius is older
        than a layer with low rib count Chesapecten madisonius, which is
older
        than normal Chesapecten madisonius, just as we know that an undated
        scrap of paper that identified Jefferson as the current president
        would be older than one citing Madison as the current president.

        --
        Dr. David Campbell
        425 Scientific Collections
        University of Alabama
        "I think of my happy condition, surrounded by acres of clams"

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Received on Sat Oct 17 13:03:22 2009