Thank you for the good references on paleosols.
About reefs,
>
>S> What about a limestone on top of thousands of feet of flood deposits
>S> containing an in situ coral reef with associated fragile crinoids or
>S> bryozoans preserved as well?
>
>K> In many such reef structures the fossils are not really organically bound,
>K> but are suspended in the matrix. Capitan Reef, for example, has been
>K> recognized as a gigantic debris flow. Some reefs that show organic
>K> structure are oriented upside down. They were probably transported from
>K> where they grew -- which would suggest high-energy water movement. The
>K> reef problem is very interesting.
>
>S> Capitan reef has NOT been recognized as a giant debris flow (except maybe
>S> by young-earth creationists who, once again, cannot have even one in
>situ reef
>S> in the geologic record or their model collapses). I refer interested
>people
>S> to a neat web site at:
>S>
>S> http://www.science.ubc.ca/~eoswr/slidesets/guad/slidefiles/guadc0.html
>
>K> Actually, I was indirectly quoting a person on a GSA fieldtrip to Capitan
>K> Reef who looked at the evidences for turbiditic structure (classical Bouma
>K> sequences) in the Yates formation (in the "backreef"), if I remember
>K> correctly, one who believed in long ages but recognized evidence of rapid
>K> emplacement of this whole set of formations. That may not be the accepted
>K> view in the present literature, but on that fieldtrip many of the men
>recognized
>K> it as such.
>
> It's not uncommon to find breccias and debris flows in the forereef or
>backreef
>areas around large reefs like Capitan (as a matter of fact, they're
>expected). That
>has no bearing whatsoever on the question of whether or not the reef
>itself is in situ.
>
We saw some angular gravels also inside Carlsbad Caverns, which is called
the reef core. There is an awfully well-defined line between the bottom
of the reef core and the reef talus, with less than about 10 m. relief,
which doesn't match with the way reefs grow in the ocean.
Currently as far as I am aware, the most accepted model for Capitan Reef is
that it is an underwater bank. I have heard that there is a new publication
coming out this spring as SEPM Concepts in Sedimentology and Palentology
No. 8, entitled "Geologic Framework of the Capitan Reef" the editors are
Art Saller and Paul M Harris. It will probably present a variety of
opinions.
Aside from Capitan Reef, other structures once interpreted as reefs have
been reinterpreted as debris flows. For example, you could look at
Mountjoy EW, Cook HE, Pray LC, McDaniel PN. 1972. Allochthonous carbonate
debris flows worldwide indicators of reef complexes, banks or shelf margins
Stratigraphy and Sedimentology, International Geological Congress, 24th
Session, Section 6, p 172-189, which describes five examples.
>S> I would also remind people that reefs are EXTREMELY common in Paleozoic
>S> carbonates around the world.
>
>K> That's where the upside-down (obviously transported) one I mentioned is.
>K> Bioherms like that one were clearly transported as a unit. Other "reefs",
>K> without real organically bound fossils (apparently not in situ coral reefs,
>K> but still called "reef structures" because of their shape) were transported
>K> broken up in limey mud from the area(s) where the organisms had grown.
>
> Just because SOME bioherms found in sedimentary rocks were transported
>doesn't
>mean that ALL were therefore transported.
True.
You've searched for examples of transported
>reefs and found a couple, big deal. You're ignoring the bulk of them
>which clearly
>formed in situ (e.g. Silurian pinnacle reefs around the Michigan Basin to
>name one
>group of them).
>
I don't mean to ignore them. One interesting thing about some of those is
that it is possible, at least for the ones that sit on Precambrian
basement, that they are true preflood reefs that did grow in place. They
would of course have species that are also found apart from any reef, in
sediments assigned to the Ordovician, Silurian, etc., so they would be
called Silurian (or Ordovician,) themselves, and yet would be truely in
situ reefs.
>S> Funny thing how, if they're all transported,
-- and even if some are really in situ --
that only tabulate corals ended
>S> up in Devonian/Silurian age rocks while Cenozoic rocks just have
>scleractinian corals
>
>K> Yes! While many other classes of Coelenterates (Porifera, Hydrozoa, and
>K> even Alcyonarids (Octocorallia, the "soft corals") continue through the
>K> permo- triassic transition fairly smoothly, the Tabulata and Tetracorallia
>K> die out entirely, and Scleractinians (and other Hexacorallia) begin. To
>K> me, this points to a possible sensitivity of the Tabulata and
>K> Tetracorallia, which caused their extinction when conditions changed.
>K> Perhaps the waters where they lived (with trilobites, brachiopods, and the
>K> rest pf the Paleozoic marine organisms) were not as saline as our seas are
>K> today, and these corals, in contrast to many of the other forms, could not
>K> survive inundation with water of greater salinity (or some other
>K> condition). Whatever it was, they did not survive. The lack of
>K> scleractinian remains with them indicates to me that the scleractinians did
>K> not live in the same place. They are found with Mesozoic (and Cenozoic)
>K> fossils, so I believe they lived in the waters of areas inhabited by
>K> "Mesozoic" animals, and they survived to speciate in the postflood seas.
>
> Once again, other than your ad hoc pleading, you are presenting no evidence
>that Cenozoic, Mesozoic, and Paleozoic organisms inhabited different
>environments.
>
I am taking the fossil record as ex-post-facto evidence.
>S> (makes a lot of sense from an old-earth, evolutionary point of view,
>
Old earth evolutionists take the fossil record as ex-post-facto evidence, too.
>K> Do you think the Scleractinians evolved from Tabulates? Or a common
>ancestor?
>
> I think it's an observable fact that Tabulates lived and thrived many
>millions
>of years earlier than Scleractinians and that different groups of
>organisms (not
>just cnidaria) were the dominant reef-builders at different periods of time.
>
> I don't know enough about the evolution of cnidaria to discuss their
>phylogenetic
>relationship.
>
How do you see millions of years as an observable fact?
>S> none whatsoever from a young-earth or flood-model view).
>
>K> Depends on your viewpoint. Making sense out of the fossil record from a
>K> flood perspective is a challenge and a joy to me. There is always more to
>K> be learned.
>
> There's more to be learned, I'll grant you that!
>
> We all have to examine our motives. If we're doing research hell-bent to
>prove or disprove some particular idea that we're emotionally attached to,
>then I think we should step back a bit and examine whether or not we're really
>looking at the evidence fairly.
>
I agree.
Karen