Summations Only

See Web-based Interactive Landform Simulation Model -- Grand Canyon (WILSIM-GC) Parameters, also referenced in my Message 1171. It references an estimate of the average slope retreat based upon studies of animal droppings.There are other estimates, but they tend to be complicated because they pose variable rates of slope retreat as a function of time period and position along the canyon, e.g., Rates of river incision and scarp retreat in eastern and central Grand Canyon over the past half million years: Evidence for passage of a transient knickzone.--Percy

No one else accepts your explanations either. Geologists look at the Coconino/Hermit boundary and say its a disconformity. That means the top of the Hermit is eroded. The short 20-foot stretch contains no erosion channels, but other sections of the boundary do. You're right, he doesn't say that. There are apparently no Schnebly Formation represented in the Grand Canyon, not even the inch I thought I saw in this image: See that skinny layer at the top of the Hermit and bottom of the Coconino? It doesn't look like it belongs to either layer. I wonder what it is. Right. I didn't listen that far the first time, I listened for a full minute this time. I don't like videos because I read far faster than people talk. Sure, of course - it's rock. You're inventing things again. People have little trouble walking across flat landscapes. But any minor unevenness is irrelevant because I wasn't comparing those landscapes to the Hermit Shale. You claimed that erosion makes landscapes uneven, and those images show that erosion flattens and evens a landscape.You ignored most of the issues I raised, namely:

• About "knife-edge tight", you're no longer claiming that it means a lack of gaps, right?
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• Do you understand that Baumgardner concedes that erosional channeling at formation boundaries exists?
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• Did you see the evidence of tectonic cracks in the Hermit Shale that filled with Coconino sand, as well as the explanation for how it happened?
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• Have you really changed your views on unconformities and now believe that "some erosion in a contact is the usual thing"?
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• Do you understand that you can't extrapolate a 20-foot stretch of strata boundary to the entire strata boundary?
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• Do you understand that the reason the boundary in that 20-foot stretch stands out so clearly is not because it is much different from that boundary in the rest of the canyon, but because that particular stretch of canyon wall just happens to be vertically flat, so the boundary stands out very clearly. It looks like the Hermit Shale (softer) eroded back underneath the Coconino (harder), causing the Coconino to shear off in flat vertical slabs. Since there is no debris at the base of this piece of canyon wall it must have been removed by canyon staff to make the wall easier to approach and view close up. As I mentioned, this is accessible down one of the most popular trails at the Grand Canyon, the Bright Angel Trail.

--Percy

No one is "getting" anything you say. Most of it is either fantasy or just plain wrong. You're determined to keep God out of the Flood, but your ignorance of how nature actually works results in impossible ideas, and so they may as well be miraculous anyway. For convenience, here's your favorite diagram again: When you call the Kaibab Uplift the "linch pin...of all the tectonic disturbance in the entire area", how could it have anything to do with the uplift at Cedar Break?How did the Supergroup layers tilt without affecting the layers immediately above, especially since the layers above had a lesser weight of layers upon them than the Supergroup and should have been easier to tilt or at least deform?How did the uplifting Supergroup layers cause the uplift of the Paleozoic layers to the immediate north of the Supergroup?Why do faults between the Supergroup blocks extend down into the Vishnu Schist but not up into the Paleozoic layers if the Paleozoic layers were already there when the tilting occurred?Where did all the cubic miles of missing material from the tilted Supergroup layers go? And the evidence that this isn't pure fiction is? What information (from the diagram or anywhere) tells you that the cause of the Kaibab Uplift and of the magma dikes were one and the same?What information tells you that the top strata of the Grand Staircase were broken up by "general shaking" causing geologic structures like the Pink Cliffs, the Grey Cliffs, the Vermilion Cliffs and the White Cliffs?The information we actually have tells us that the northern end of the Grand Staircase began eroding away with the uplift of the Colorado Plateau about 13 million years ago (see Geology of the Zion and Kolob canyons area). The uplift caused cracks in the strata which were opportunistically exploited by rivers such as the Virgin River. River flow in this region is episodic, being very light and slow much of the year but experiencing flash floods in the spring, hence canyon walls tend to be very steep because of rapid downcutting. What information tells you that the Hurricane Fault occurred at the same time as the general uplift of the Colorado Plateau, the Kaibab Uplift, and the magma dikes? By shaking you mean earthquakes? What evidence are you looking at that tells you the region experienced earthquakes that caused the cracks and joints in the rock? How do you know the cracks didn't form gradually from tectonic strain? Since a very common cause of earthquakes is movement along fault boundaries, the faults have to already be there before the earthquakes. It's hard to understand what you're saying here. Is there a granite layer you're referring to that is not the Vishnu Schist?And how do you have the layers forming at the same time as the uplifts? Don't the layers have to be present before the uplifts and erosion, rather than forming at the same time they're being uplifted and eroded. The Paleozoic layers couldn't form before the Vishnu Schist below them, so how could they be uplifted and shaken and cracked before they even exist? I don't know if you realize it, but the way you've described everything has deposition of strata happening at the same time as uplift and cracking of strata and of erosion of the strata. The impossibility of this should be obvious. What evidence do you have that says a tectonic event in the Grand Canyon region was responsible for the splitting of the continents? The dating of the breakup of supercontinents like Gondwana, Laurasia and Pangaea do not correspond to the dating for the uplift of the Colorado Plateau or the Kaibab Uplift. Since there have been multiple supercontinents that broke up in Earth's history, which one are you imagining is the one that broke up? There is no evidence that the movement of tectonic plates has ever been outlandishly fast. The speeds of the various plates ranges from 1 to 10 cm/year. I just provided the range of plate speeds. 2-3 centimeters per year is true of the North American Plate, but the Pacific Plate moves about 10 centimeters per year. There is no evidence that plate speeds have been dramatically different in the past than they are now - plate boundaries and sea floors provide copious evidence of plate speeds. Certainly speeds less than a centimeter per year are possible. Speeds greater than 10 centimeters per year are likely also possible, but not by a great amount, and certainly not the miles/day required in your flood scenario. What evidence and rational leads you to believe that rapid plate motion began when the flood waters began to recede? Where is the evidence of this "something happened on the sea floor"? "Under the continents"? Water draining? That it caused the Atlantic ridge?Why do you think volcanism only began with the breaking up of the continents, since volcanic ash and magma is easy to date, those dates don't support your scenarios, and there is copious evidence of volcanism throughout Earth's history. You can be as unconventional in your thinking as you like as long as you have evidence for what you think and your scenarios obey known physical laws and aren't miraculous.--Percy

Oh, I thought you were referring to something more than what you said in Message 1140. If that message is what you want to stand on, then concerning Walther's Law you said: The flume stream in Bertault's experiment is a) nothing like a flood; and b) does something that is not part of Walther's Law, which is to build diagonal sediments laterally. In Bertault's experiments a flume of sediment laden water build strata laterally across his tank at an angle of around 45 degrees. Look at time 5:50 to see the slant of his strata. Does that look anything like what we find in the geologic record? . Does that look anything like Walther's Law to you?About fossil order you say: This has a major problem all by itself without even looking at the video. According to you all fossils are the same age. If Bertault is exploring a scenario where the fossils are of different ages then he does not share your views.And floods cannot sort by age or by difference from modern forms. Floods will sort by size, density and shape, plus in a flood there's a large random element. So if you dump fossils of different ages and forms into a flood they'll be sorted by size, density and shape. That means that an older fossil could end up above a younger fossil. It means that a fossil very different from modern forms could end up above a fossil very similar to modern forms. But nothing like that is ever found in the fossil record.--Percy

That wasn't really my question. My question contained important context that this ignores. My actual question was: That's the question I asked. Rephrased, if discussion here upsets you so much, why don't you find something to do that you enjoy more and that makes you feel good? Thinking must be based upon knowledge of the real world and driven by evidence to have value. Your thinking is based on an eclectic personal interpretation of a religious book that you try to impose upon the real world. When you encounter disagreement it often makes you upset and unhappy. This causes you to say things like, "The thought of trying to explain any of that to you gives me a stomach ache," and "You do seem to make what to me is a small point into a huge problem and it just seems endless and impossible to find a way to explain something clearly to you."--Percy

I'm going to start with your last paragraph about whether the Coconino/Hermit boundary is really a disconformity: I first saw it mentioned that the Coconino/Hermit boundary is a discontinuity at the Wikipedia article on the geology of the Grand Canyon area:

quote:

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Like the Supai Group below it, the Permian-aged Hermit Formation was probably deposited on a broad coastal plain (see 6a in figure 1). The alternating thin-bedded iron oxide, mud and silt were deposited via freshwater streams in a semiarid environment around 280 million years ago. Fossils of winged insects, cone-bearing plants, and ferns are found in this formation as well as tracks of vertebrate animals. It is a soft, deep red shale and mudstone slope-former that is approximately 100 to 900 feet (30 to 274 m) thick. Slope development will periodically undermine the formations above and car- to house-sized blocks of that rock will cascade down onto the Tonto Platform. An unconformity marks the top of this formation.

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I wasn't sure whether to trust this information, but then I found more information, and it addresses what you say about little of the Hermit Formation being lost to erosion: This is from The Grand Canyon Panorama Project: Hermit Shale:

quote:

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The boundary between the Coconino and the Hermit Shale is quite remarkable. Here, on the North Bass Trail, we are just a few feet away from the boundary, and you can see that the rocks switch completely from the light tan Coconino to the dark red Hermit in just the space of a few inches. You might think that some huge environmental change took place in the geological blink of an eye to create this sharp boundary, but in fact there is an unconformity between the formations, meaning that the Hermit Shale was exposed on the surface and eroded away for some millions of years before the sands that formed the Coconino began to be deposited.

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But obviously you think this is wrong, and I've read that the Hermit Formation is one of the least studied layers, so maybe you think this information shouldn't be trusted? Yes, thanks for mentioning this. I discovered I was wrong about this and was going to work it into an upcoming message, but this saves me the trouble. I thought I'd discovered evidence of tectonism, but no such luck.--Percy

You posted three replies to my Message 1215. I'll reply to them here in this message.Replying to your Message 1216: Okay, let's call it the contact line. It's about one inch thick. How is that a "knife-edge tight" boundary? Here's the image for reference: Replying to your Message 1219: I think the only difference between me and everyone else is that no one else is pushing you as hard on this point. Pretty much no one accepts your explanations. How do you know you're not the one with paradigm blindness who needs to be smart enough or honest enough to get it?If the facts support your position then discussion will bring that out.Replying to your Message 1220: Oh, this sounds like your idea that the flood repeatedly advanced and retreated across the land due to tides, all while maintaining its loads or sorted sediments and fossils. One should not eschew interpretations for any other reason than that the evidence does not support them. In Message 1203 you said, "The contact as shown in that picture with the arrow is just one single line with no gaps,..." It's one single fine line that is about one inch thick, hardly "knife-edge tight." There's no ambiguity about where the boundary in the image is. No I couldn't, sorry. You don't mean "computer science" but "application software." We are all frustrated at the general regression in capability and quality in application software as the software industry increasingly caters to the nether regions of computer competence. And as more and more of the population transitions from computers to mobile platforms, fewer and fewer development resources are available for computer applications. For one example, in Windows 10 Microsoft replaced Paint with Paint-3D. Definitely not an improvement. Given the many examples of erosional channeling in many strata boundaries, a 20-foot stretch of boundary that has no erosional channeling means nothing. Uh, in your previous paragraph? Oops, too late. Sorry. I'm just calling attention to the implications of what you say. Except that is neither knife-edge tight nor unique. The Coconino/Hermit boundary is pretty much the same everywhere throughout the Grand Canyon. What is unique about the section in that image is that it is easy to get to on the Bright Angle Trail, and the flat vertical wall of Coconino at that location makes the boundary especially easy to see.--Percy

I just noticed I never replied to this. I understood most of your explanations and so there was no need to reply, except I have a comment about this one part: Speaking just for myself, thought I think this is true of more than just me, this is one of those things I "know" because it is an inevitable consequence of other things I know, but I never thought about it before. Radiometrically, stratigraphic layers not only increase in age with increasing depth, but also laterally backward along their path of formation. It's another facet of the radiometric qualities of the strata that no flood could produce. Thank you for this, such a fine sight to see. And thanks to Jar for his description. I thought the mural was a real storefront and missed the reflection and the girl. A just checked out the Wikipedia entry on Standin' on the Corner Park, and it mentions that the animated film Cars was set along Route 66.--Percy

Edge has convinced me that some of what I've read on the net about the Coconino/Hermit boundary is incorrect. What seems likely true is that that boundary lacks erosional channeling wherever it is visible in the Grand Canyon area. Here's the link again to Baumgardner's article: Noah’s Flood: The Key to Correct Interpretation of Earth History. Here's the part I was referring to:

quote:

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Figure 15. View of the contact between the Coconino Sandstone (above) and the Hermit Shale (below) in the Grand Canyon along the Bright Angel Trail. Note the lack of erosional channeling along this contact.

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He seems to be implying that there is no erosional channeling anywhere in the Coconino/Hermit boundary, and if he is then he is likely correct. So I'll repeat what I said earlier: Edge has convinced me that some of what I read about this boundary is incorrect, and that it is likely true that there is no erosional channeling in this boundary. Repeating again what I said just above, there is likely no erosional channeling visible in the Coconino/Hermit boundary in the Grand Canyon area. That short section is not unique but typical. What's unique about that section is not the boundary itself but rather how clearly the boundary stands out because of the vertical flatness of the Coconino wall and how accessible it is along the Bright Angel Trail. Here's that short section again, and note how vertical and flat the Coconino layer is: But there are other places in the Canyon where the boundary is just as clear, it just isn't as accessible and you can't just walk right up to it, as here: Again, you are correct. Edge believes the boundary is more a diastem than a disconformity. Edge believes these are mud cracks formed by drying (which can only occur while exposed to the air, not while buried or submerged), and since he said that I've found other references describing the same thing. For example, this is from the Wikipedia article on the geology of the Grand Canyon area:

quote:

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Some Coconino fills deep mudcracks in the underlying Hermit Shale...

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--Percy

After you've watched it again you can get back to us. What floods do is common knowledge. Floods happen all the time. That's pretty close. If you look up "flume" you'll find that it is "a deep narrow channel or ravine with a stream running through it." Bertault was creating artificial flumes in the laboratory. A river is not a flume, and a rising flood is like neither a river nor a flume. Again, look at time 5:50 and see the slant of his strata. To help you out, here is the video already primed to start at exactly time 5:50: He is showing an image of the layers right in the middle as they are forming, and they're all at an angle of 45 degrees (or thereabout). Not mentioned in the video is that he is feeding his "sediment" load into the flume at the other end (the left end) where the water feeds in. There are no sediments being held in suspension in some reservoir analogous to the flood.--Percy

Not really. For the most part you have a very poor intuitive sense and little knowledge of how the world really works. The views you express here are primarily based on what you wish occurred given your religiously based beliefs of what must have happened. This drives an interpretation of the evidence at all odds with the physical world. Another possibility is that you don't understand many of the implications or significance of your many misguided claims. The contact boundary of the Coconino/Hermit is unambiguous and can't be missed. It is also about an inch wide and definitely not "knife-edge tight". Here's the image: --Percy

Calling it a sharp contact seems fine, though I'm still wondering what that inch of "something" is.--Percy

I think you're mistaking a shadow for a "fine dark line". If there were truly a thin dark layer of strata at the bottom of the Coconino then it would not go completely unremarked upon by geologists.And if what you're calling the "one-inch thick beveled part" were truly part of the Hermit, then why isn't it the same color as the Hermit? It is instead the same color as the Coconino. Well, I do agree that this Coconino/Hermit contact isn't very relevant now that Edge has pointed out that some of the things on the web about it are incorrect, such as the discontinuity being millions of years old. Edge doesn't even believe it's a discontinuity but a diastem. That's the benefit of discussion, you learn things.But I think the feeling you express that the issues I've raised (which are pretty much the same issues others have raised) are "a billion irrelevant tedious questions" is more a reflection of your inability to provide answers. Well, yes, I can understand how someone who doesn't like their ideas questioned would feel this way. The issues that remain unanswered are:

• You say that erosion between strata is due to runoff. How do you envision the flood repeatedly advancing (deposition) and retreating (erosion) across the land due to tides all while maintaining its loads of sorted sediments and fossils? How do you explain ancient stream and riverbeds?
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• Why do you think Bertault's experiments support the flood given that they a) deposit strata at a 45 degree angle; b) require a flume rather than a flood; and c) postulate fossils of different ages?
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• Given that Bertault's ideas are so contrary to your own, why after so many years of arguing for Steno's unaltered views from centuries ago were you so quick to abandon Steno just on Bertault's say so.
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• How could a single tectonic event beneath what is now the Grand Canyon be responsible for everything we see in the Grand Staircase region, not to mention the breakup of continents?
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• What evidence leads you to believe that the Kaibab Uplift, the Hurricane Fault, the magma dikes, and I assume the Sevier Fault, too, though you haven't mentioned that yet, all happened at the same time?
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• What evidence leads you to believe that the top strata of the Grand Staircase that are now missing were broken up by "general shaking" that causing geologic structures like the Pink Cliffs, the Grey Cliffs, the Vermilion Cliffs and the White Cliffs?
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• What evidence tells you that continental drift used to be much faster than it is today?
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• What evidence tells you that this great speed of continental drift only began at the end of the flood?
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• You say that, "Something happened on the sea floor and under the continents that broke them apart and caused the water to drain, began the Atlantic ridge, began volcanism which gets triggered with the movement of the continents and so on." What is the evidence of this something that happened on the sea floor, and that it caused all these events?
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• What evidence is there of a tectonic event creating a drain on the ocean floor for flood waters? What evidence is there for fountains of the deep?
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• Since 3/4 of the globe is currently covered by water, how is a truly global flood that covers the remaining quarter much different?
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• Did you never wonder why no fishermen were able to get to their boats and survive the flood? Maybe that's who populated the land of Nod, where Cain's wife came from.
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• Why do you think volcanism only began with the breaking up of the continents, especially since volcanic deposits are easy to date showing that there has been volcanism throughout Earth's history?
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• If the Paleozoic layers were already present when the Supergroup layers tilted, why do the faults associated with the Supergroup extend down into the Vishnu Schist but not up into the Paleozoic layers?
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• If the Paleozoic layers were already present when the Supergroup layers tilted, then given that the weight of the Paleozoic layers was less than the weight upon the Supergroup layers, how were they able to resist tilting while the Supergroup layers could not?
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• If the Paleozoic layers were already present when the Supergroup layers tilted, then where did the cubic miles of rock of the now-missing portions of the Supergroup strata go?
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• If the Grand Canyon had been cut suddenly then the canyon walls would be vertical. How do you explain the sloping walls of the Grand Canyon?
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• What evidence suggests to you the extended periods of tectonic quiescence, particularly far from plate boundaries, is unusual, particularly in light of the many other parts of the world that have extensive strata without much faulting or deformation?
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• Why do you think the Great Unconformity is worldwide extent, especially given the presence in many parts of the world of strata from time periods represented by the Great Unconformity?
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• How do you explain the distribution of fossils in geological strata according to increasing difference from modern forms?
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• How do you explain the increasing radiometric age of strata with increasing depth?
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• How does a flood carry sediments thousands of miles across a continent and then separate them by type (not by size or density) and deposit them with distinct boundaries?
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• What evidence leads you to conclude that there is detachment along the Great Unconformity?
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• Why did you say that, "Radiometric dating is just not going to fly with me, it's all a bunch of conjectural stuff, not real evidence." What examination of the evidence led you to this conclusion, especially since even the RATE group found no problems with radiometric dating?
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• Do you now understand that erosion flattens and levels landscapes? If not why not?
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• AbE:
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• Why did sediments only deposit on land and never on sea floors?
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• The amount of scree and talus and rocks and boulders in the Grand Canyon greatly exceeds what could erode off the canyon walls in a mere 4500 years. How do you explain that?
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• How did the flood leave behind cross bedded sand dunes with animal tracks in the Coconino?
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• How did the flood transport and deposit sediments that include burrows, termite nests, worm holes, etc.?
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• Your scenario requires repeated inundations of the land to build the individual sedimentary layers. Each inundation delivers and deposits the sediment for a new layer, followed by a recession, and then the next inundation delivers and deposits new sediments for the next layer. If receding flood waters carved the Grand Canyon, then how is it that the receding waters between each inundation did not carve canyons, even small ones?
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• Here's a thought experiment about receding flood waters carving the Grand Canyon. Imagine a bathtub with a massive drain that can empty the tub in seconds. Fill this bathtub with water. Build a pile of sand in the middle that doesn't quite reach the surface. Open the drain. Why is there no flow of water across the pile of sand and no erosion?

--PercyEdited by Percy, : AbE.Edited by Percy, : Minor revision.

That would be incorrect. The shadow isn't present along the entire contact. It's easier to see in the other image that the shadow is due to the Coconino sticking out just a little bit above the Hermit. This makes sense since the Hermit is softer rock than the Coconino and erodes more quickly. Here's the other image. Be sure to click on it to expand it, it makes it much easier to see the Coconino sticking out a bit above the Hermit: Well, glad to see you never start anything. You called it a "fine dark line", not a shadow, so I assumed you thought it was something real rather than an artifact of the light, which means it would have to be a fine dark line of strata at the bottom of the Coconino. I was merely describing how what you said implied something that couldn't possibly be true. *I* understood it was a shadow, which is why I said, "I think you're mistaking a shadow for a 'fine dark line'." The image above reveals there to be no bevel. That little inch-wide section is just as vertical as the rest of the rock face. The "fine dark line" is a shadow, and we still don't know what that Coconino-colored inch-wide section is. This would be incorrect, on a couple counts. First, I did not misread the photo.Second, that section of Coconino is not "unique as such a tight contact in the whole Grand Canyon." In my Message 1254 I provided an image of the Coconino/Hermit boundary from elsewhere in the canyon, and it looks exactly the same. You replied about it in your Message 1260, so I'll address that here: I think your eyesight may be limiting you here. Here's the image again: The lower left of the image contains a blowup (bordered in yellow and labeled "B") of the section of the rockface that is pointed to by the yellow line in the main image that is labeled "A". Click on the image to expand it and look at the blown up section in the lower left. You'll be able to see that this section of the Coconino/Hermit interface is just like the one from the Bright Angel Trail, with that little inch-wide something between the Coconino and the Hermit, and with shadows cast from the Coconino because it sticks out just a tiny bit further from the rockface below it. I think if you stick with the discussion that you'll see the images support what I've been saying.So what about all those other issues?--Percy

Replying to your last few messages...Replying to your Message 1264 to me: As others have noted, without knowing the nature of that inch-wide something (whether it belongs to the Coconino or Hermit or is a transitional zone), it can't be known whether the term "knife-edge tight" is appropriate. But for the sake of discussion let's say we agree that the Coconino/Hermit boundary is "knife-edge tight." Since many strata boundaries in the Grand Canyon and at many, many places around the world are "knife-edge tight," why do you believe this significant? Hey, we agree on something! A "knife-edge tight" contact would be too narrow to have a shadow be cast that is in it. Do you sense of pattern here of casting blame instead of deliberating towards a resolution? Well, *something* is an inch thick. No one is contending that you're wrong that the inch-wide something belongs to the Hermit. Edge also seems to lean in that direction. The question is how you know, from a photo, that it belongs to the Hermit? While it doesn't matter to the larger discussion whether it does or not, there is an important point here, and that's that people can't just declare things so. They have to show that they're so. That's why Edge and Tanyperyx and HereBeDragons tend toward characterizations couched in tentative terms when there is insufficient evidence for solid conclusions. So why do you think the "lighter band beneath the contact doesn't belong to the Hermit"? If everywhere you go there's a problem...guess what?Replying to your Message 1266 to HereBeDragons: We do understand that you believe the Grand Canyon was formed rapidly by receding flood waters through massive erosion of still unconsolidated sedimentary deposits. This raises a couple additional questions:

• Your scenario requires repeated inundations of the land to build the individual sedimentary layers. Each inundation delivers and deposits the sediment for a new layer, followed by a recession, and then the next inundation delivers and deposits new sediments for the next layer. If receding flood waters carved the Grand Canyon, then how is it that the receding waters between each inundation did not carve canyons, even small ones?
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• Here's a thought experiment about receding flood waters carving the Grand Canyon. Imagine a bathtub with a massive drain that can empty the tub in seconds. Fill this bathtub with water. Build a pile of sand in the middle that doesn't quite reach the surface. Open the drain. Why is there no flow of water across the pile of sand and no erosion?

Reply to your Message 1268 to HereBeDragons: It feels insensitive to question anyone's health-related issue, but I have to agree with HereBeDragons that the timing of your lapses of vision has often seemed very convenient for you. Potentially productive lines of discussion have often been left hanging because you claim you can't see the images. You say images with a lot of white are difficult for you, but much text on the web is black on white, which doesn't seem to cause you a problem. Your frequent descents into sarcasm, complaint, blame and insult are often well-timed to thwart discussion, and this casts doubt on the sincerity of your commitment to reach mutual understandings, leading to the suspicion that your vision impairment claims might just be another arrow in your quiver of evasive tactics. I think we all want to be respectful of your vision challenges, but we don't want to be played for fools, either.Replying to your Message 1270 to Tanypteryx: Something is an inch thick, and it lies right at the Coconino/Hermit boundary. Instead of taking the word of this "someone" you should accept the evidence before your eyes. Maybe it isn't that you can't fathom but that you can't see. What "fine line" are you talking about? Is this the "darker fine line" that you still haven't revealed whether it's the shadow or something else? Your eyes are telling you things that aren't there. The inch-side something is very unlikely to be at an angle. Here's the image that shows it best. The best that you can claim after viewing this image is that while it doesn't render it impossible that the inch-wide something is at an angle, it definitely doesn't look that way in the image. Click on it to expand: Again, what do you mean by "fine line"? Where there's no shadow there's also no line. Look at the first vertical line from the left of sheered off rock in the Coconino layer. Where this vertical line meets the inch-wide something there is no shadow and no line. The Coconino transitions abruptly into this inch-wide something.This particular image also has pretty fair resolution. Blowing it up reveals that the texture of the inch-wide something is different from the Coconino, and it is different in both texture and color from the Hermit. Whatever this thin layer is, it is unlike the layers that adjoin it. Now maybe it's just that the very earliest Coconino deposits were different from those that came later. Or maybe it's some mixing of the Coconino and Hermit. Or maybe it's something else. I don't know, I'm not a geologist and I'm not there where I could study it anyway. Is there a rule that says a "knife-edge tight" contact can be an inch thick?Edge calls it a sharp contact, and I give informed views very serious consideration, but I also have to give serious credence to what I can see with my own eyes in that image. That inch-thick something is not the same as the layers above and below it. That will be obvious to anyone with decent eyesight and a high-resolution monitor. My Macbook Pro is 2880x1800.As Edge says, the inch-wide something is slightly recessive, hinting that it belongs with the Hermit. Also, the slabs of Coconino broke off at the top of it instead of the bottom, also hinting that it belongs with the Hermit. But Edge also mentions that in color it looks sandy, which isn't like the Hermit at all.There's no way to tell what's really going on from an image. A geologist would probably walk up to the rock face and take samples above, below and at the inch-wide something that he then subjects to multiple analyses, which would certainly include examination by both eye and under a microscope, and I don't know what else. But even though we sitting here in our easy chairs have to concede that we can't possibly know the answers, that doesn't change the fact that the image alone tells us the inch-wide something is not the same as either the Coconino or the Hermit. Well, yes follow the discussion. There is an inch-wide something at a contact you've called "knife-edge tight." You've called this contact unique, yet I've shown you an image of an even longer stretch of the Coconino/Hermit contact that looks just like that one, and here's yet another image of a different location where the Coconino/Hermit contact is just as clear and obvious as it was at other locations: But there are many, many miles of sharp contacts between layers in the Grand Canyon. They're just not as easy to see because they're not below the Coconino that breaks off in slabs, which makes it easy to see the boundary with the layer below. Many Grand Canyon strata contacts are just as tight, but it's harder to see them because the strata are softer or there's a lot of scree or they're the same color or there's vegetation obscuring it or something else or some combination. For example, this is Vasey's Paradise in the South Canyon of the Grand Canyon. It has a boundary between the Muav and the Redwall Limestone that has a sharp contact. Can you pick it out? I couldn't: Replying to your Message 1272 to Tanypteryx: Not helpful. Again, what "very fine line"? There's a shadow, but no line. There's a contact line between the bottom of the Coconino and the top of that inch-wide something. Is that what you're referring to? Without knowing what that inch-wide something is, without knowing whether it belongs to the Coconino or the Hermit, how can you know whether "knife-edge tight" is an appropriate description?Here's some irony. This paper by John Whitmore, a creationist (Sand injectites at the base of the Coconino Sandstone, Grand Canyon, Arizona (USA)), mentions "bedded sandstone clast breccias in structureless sandstone lenses at the base of the Coconino" in the abstract. I don't have access to the paper and can't get more detail, but maybe Edge or Tanypteryx or someone does. But clearly he's saying something is going on at the base of the Coconino.This earlier paper by the same creationist author, Sandstone clast breccias, homogenized sand, and sand intrusions: Evidence of substratal liquefaction in the basal Coconino Sandstone (Permian), Grand Canyon, Arizona, says in it's abstract:

quote:

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Field evidence and thin section analysis suggest the base of the Coconino Sandstone underwent substratal liquefaction prior to lithification of the unit. Previous work has indicated that the large sand-filled cracks often found at the base of the Coconino, penetrating into the Hermit Formation, are probably not mud cracks, but intrusions of liquefied sand.

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I can't get at the actual paper, and interpreting the above excerpt is beyond my pay grade (what is "substratal liquefaction" and what causes it), but it is still easy to tell that it's saying something went on at the base of the Coconino, and I'm betting that whatever it was took place in that inch-wide something. That is, this creationist paper implies that the inch-wide something is part of the Coconino, which makes perfect sense since it seems sandy and is the same color.Of course, I'd understand if you don't what to trust what a creationist author says.--Percy