You asked for an example where large layers of sedimentary rock, distinct from those above and below it, could be found. Marine platforms are just one example (I gave several others). By marine platform, I am referring to the area between the coastline and the edge of the continental shelf (where the crust becomes 'oceanic' or basaltic). GoogleEarth (or even GoogleMaps satellite view) is a great tool to see just how large this area is.jlay wrote:So, would it be OK to say that the entire globe is a marine platform?
It is true that most of the Earth's surface was submerged for at least some time in the past. But this was not at the same time, or necessarily by marine incursion. Sea level changes, so the ocean now covers areas of land that were previously exposed (e.g. the English Channel, Florida Bay, Bering Strait, Black Sea, etc.). Some areas undergo uplift (like the Himalayas) while others subside (the Dead Sea basin) and work with or against sea level. When you put all of these processes together with the global tectonic picture, we begin to see how most of the Earth's surface might contain some kind of marine rock (at least at one point in the geologic column).
For a graphic example of where marine waters once covered the Earth, visit http://scotese.com/earth.htm. Each picture is the result of thousands of paleomagnetic data points and thousands of geologic maps. The fact that these data give even a reasonably coherent picture of the Earth's surface over time tells us that the processes responsible were not chaotic and catastrophic. The transition from each time slice to the next makes sense in terms of what we know about tectonics, sedimentation, erosion, etc.
Why speculation? At the end of my last response, I described the kind of detail we can ascertain from such rocks, and how they are genetically related to modern marine environments (if you recall the story of my colleague's thesis). The sedimentary structures, chemical makeup of the rock, chemical makeup of the organic matter trapped in the rock, etc. all corroborate the interpretation that sedimentary rocks at 20k feet were once part of a marine environment.jlay wrote: It is speculation to say that sedimentary rock we see at elevations of 20k feet were formed by these methods you reference.
No, it is not. And you quoted the examples I gave where other environments produce the same. River valleys, alluvial valleys, lakes, deserts—all of these produce stratified rocks.jlay wrote:So, certainly stratified rock is not limited to what we call marine platforms.
Any introductory text on sedimentology and stratigraphy will have illustrations of such models. In short, successive layers represent adjacent environments. Sand is deposited in nearshore (beach) environments, while mud is deposited deeper in the ocean. As the coastline progrades (migrates, if you will) out into the ocean, the result will be a broad mud layer covered by a broad, distinct sand layer. In a floodplain environment (think Mississippi River Valley without all the people and artificial levees), river channels migrate across the surface. When they do, they deposit several feet of sand across their path. When rivers flood, they redistribute mud across the entire floodplain. The result is a thick "layer" of mudstone/siltstone with thinner layers of sandstone throughout the formation. One exciting part of sedimentology is that we can see sandstone "river channels" cutting through mudstone layers all the time. These sandstones commonly contain fossils of fish teeth, turtle shell, etc.—things one would expect to find in an ancient floodplain environment.jlay wrote:And I would certianly like to see the explanations regarding these modesl of how each layer is not just distinct but that is is unique in its material make up.
These are two examples out of thousands, and since sedimentology and stratigraphy was my primary focus in school, I'd be happy to elucidate further.
I do disagree. There are several methods, for example, by which we can measure the current and ancient uplift rates of mountains. None of these methods give us reason to think modern processes (or near-modern rates) would fail to account for such features. The same goes for Mid-Ocean Ridges. Please cite specifically what you mean by "the effects of erosion and sedimentation".jlay wrote:The processes we see today at the current rates would not account for the geological features. You may disagree, but when one takes into account the effects of erosion and sedimenation, this creates a problem for the surface features as we observe them today, if one is holding to gradualism.
My statement is not arbitrary just because I do not have exhaustive knowledge. If I were to say "all YECs misunderstand X, Y, or Z", then I would be guilty of hasty generalization. Rather, I said "commonly" with reference to anecdotal evidence: I have never encountered an accurate representation of uniformitarianism in YEC literature or dialog, but I have encountered numerous documentable cases where they do misrepresent it. How should I rather describe this phenomenon?jlay wrote:Unless you have interviewed all YECers, you are making an arbitrary statement.
Imagine that an ESL teacher gave a presentation at a teacher's conference, and said: "Non-native English speakers commonly misuse the article in speech." Is she also guilty of prejudicial conjecture? Is her statement arbitrary? No, she is relying on her teaching experience to reason inductively to her main point. Moreover, her statement allows for exceptions and is not meant to be exhaustive. I apologize that my statement came across as arbitrary or unfair, but if you think I am guilty of such, please provide an example against my claim.
If YECs want to attack the principle of uniformitarianism in published works and in public view (I was critiquing a book in the article you cited), they should be expected to accurately represent it. I think you would also agree that if one were accusing the biblical text of containing errors/contradictions, he/she should be expected to accurately represent it (despite the fact that he/she does not hold to its views). Nonetheless, if you follow my argument, I concluded that when YECs misunderstand uniformitarianism, they attack it unnecessarily. The attack is unnecessary, because YECs employ uniformitarianism in their own research. Reconstructing global ocean currents during the Flood is an application of uniformitarianism; reconstructing water depth/velocity during the Flood based on sedimentary structures in the Grand Canyon (cf. Steve Austin) is an application of uniformitarianism!
I've witnessed many of these presentations myself—hence my challenge. YECs have simply not addressed a vast majority of the data. The example I had in mind was the heterogeneity of carbonate platform deposits, which, to my knowledge, has never been touched by YEC geologists. Carbonate chemostratigraphy (the subject of my thesis) is another field that has never been addressed by YEC geologists. The fact that YECs, Ph.D. or not, give presentations with models of how the Flood explains geology does not mean their models actually explain the data. There is a reason, I think, these models only exist in popular-level public arenas and privately published books: most geologists understand the complexity of the data and immediately recognize the flaws in the model. It is not just a matter of philosophical presuppositions, else why do so many Christians (including former YECs) also reject these models out of hand?jlay wrote:Having witnessed presentations by YEC, phd, Geologists, I do know there are such models. However, I would imagine that ones own philosophical presuppostions are going to determine how 'better' one thinks they are.
I don't mean to sound crass here. I only wish to paint the picture as it really is. Thanks again for the interchange.
Jon
