Evidence that the Great Unconformity did not Form Before the Strata above it

You could use a flour sifter the "deposit" the sediment in even coats.But I think you would see enough effect with sand in water. Collored sand could be spread in thin layers in a glass container (old aquarium? and this would allow you to see a side section.Use a steel nut for the block and drop it down the inside face of the glass to observe the indentation\splash?Enjoy

The only sand I have is a jar of it that Coragyps sent, not enough to play around with for other purposes.I did think of using a nut and I may have some in the toolbox.Sifting the flour would work for layering and that's a good idea except that it's hard to get flour to absorb water so I'm going to have to start by mixing that up, then testing it for consistency, dropping pebbles or nuts into it to see how deep they go, before I try forming anything approximating layers.Edited by Faith, : No reason given.

Better watch yourself here, M'lady. You're turning into a real operating scientist.

That guy has a really great blog, huh? Some of the best photographs of the canyon around and he knows what he is looking at so it's not just a random picture. I've said it before... no picture can do justice to the Grand Canyon. Just calling the "Grand" Canyon is a major understatement.A couple comments about you markings. I am not sure about the Bright Angel Shale on the left side. It kind of looks like the Muav Limestone and Bright Angel Shale are in the background, but I did not think that there was a place where the Tapeats was not overlain with another formation, so I am not sure. At first I wasn't sure about the contact between the Tapeats and the Shinumo, but the more I looked at it, I think it's pretty close. But it is clear that there is Bright Angel Shale sitting directly on Shinumo Quatzite and the Tapeats pinches out against the Shinumo.ABE: Also wanted to mention that the angle of the bedding planes in the Tapeats changes as you go further to the right of the picture suggesting that it was depositing non-horizontally.Not flat!!From the same page that your image came from You were once looking for an image of the granite intrusion terminating at the Tapeats and this is a great one... except for some lady blocking the contact. **Come on, we care about the rocks, not his friends - LOL.** But, anyway, it should be clear the intrusion doesn't continue past the Great Unconformity.Also, a close up of the contact. The contact is about 6 - 8 inches wide with vishnu clasts suspended in Tapeats sandstone.I pretty sure that's not a sliding contact!HBDEdited by herebedragons, : added paragraphEdited by herebedragons, : figured I better add image I am referencing.

Actually, all bodies of water will deposit sediments as long as there is a supply. Walther's Law explains the distribution of sediment types in space and time. This is grossly simplified. Sediments are not going to just sit out there and wait for the water to do something. Sediments will be deposited immediately upon hitting slower flow regimes in the water. That's like 'right away'. It isn't 'needed', it just happens. Sure there are other types of erosion, but if you just look at Siccar Point, for instance, you can't say that the area is not eroded by wave action.You guys are talking about completely different things here and I'm not seeing the issue. If you want to see deposition by tsunamis there is plenty of evidence shown by the debris left behind. If you want to see erosion just look up 'Lituya Bay' sometime. It's all moot. Well, apparently, YECs aren't helping much, so someone has to do it. Like I said, if YECs would throw us a line, we might be able to address your arguments.

Yeah, there are some things I might question, but I will almost always defer to the guy who was there... Yes, that's the hazard of perspective. I can't tell how far in the background those outcrops are. I was also concerned about that with the unconformity, but without the heavy line it looks like the Tapeats is in direct contact with the Hakatai and the Shinumo. Again, that could be perspective, but I would say that the thickness variation is the best information. As far as a tilt to the rocks, Faith could always say that, "... well the whole area has been tilted." What we need to show is that the bedding in the overlying units is not so tilted, and it kind of looks that way, but certainty is tough unless you are there.One of the problems I have with Faith is that, yes, I can think of exceptions to almost every rule. The problem with them is that they do not fit in with other data that we may not be able to explain or see in a picture. I'm fairly confident here since IIRC, McKee had a schematic showing the same relationship. Yes, on a gentle surface, I'm sure that this is happening. Nevertheless, I think a lot of it has to do with compaction upon sediment loading, dewatering and lithification. In that case, we can say that Faith is partly correct, except that it would contradict her whole tectonic interpretation. Yes, this is a good example. The point is that there is NO PLACE where such intrusions cross the unconformity (the older grantitic intrusions, that is). Of course that could be the 'black swan' fallacy, but until we see one, it is the interpretation. It surely doesn't look like it. Shearing imparts a fabric to the rock and I have never seen a shear/fault plane without some evidence of a sheared fabric.

Yea, I think this drawing may be that same location. Pretty cool!HBD

One of the problems I have with water and water is that you will end up with more of a batter than particles in suspension.The reason for trouble mixing is surface tension, so you could add soap or (wood) alcohol to the water to cut that down.Enjoy

Heh, this is weird. I was researching the source of sand for the Tapeats Sandstone formation and found a reference by Art Chadwick, renowned YEC, who makes the following statments: The geological term 'dip' is the inclination of bedding planes in a rock body. This seems to indicate that irregular surfaces related to the unconformity on the Precambrian rock surface influence the orientation of the subsequent Tapeats sandstones.Does this mean that we can finally dispose of Faith's argument that the Great Unconformity is:1. not erosional in nature, and that2. it is "straight and flat"; and that3. strata cannot be deposited in a non-horizontal orientation?Or is this all just evidence for Faith's historical geology scenario?

I have either finely powdered sand or limestone too, Faith. And I still have your address if you want either. None of the dough-forming properties of wheat flour, and both are gluten-free as well.

Wow, I could build my own Grand Canyon almost! Thank you but I feel bad that I haven't done the experiment yet and I didn't even get out to look for pebbles today. Let's see if I get this done before I ask for more. But that's nice to know.

You need to explain what Chadwick meant because I can't answer your questions as is.ABE: Never mind, I figured it out.Edited by Faith, : No reason given.

Yes it will be more like a batter but I think that should work for the dropstone experiment. It wouldn't work for the horizontality experiment of course. It also makes paper mache glue, so when I'm finished I can make a piata. And if it really doesn't work very well then I'll start over with sand.Edited by Faith, : No reason given.

No. No, because it is straight and level where I showed that it is, so erosion didn't create that section... Still need to do some experiments for that. Ya never know.
Edited by Faith, : No reason given.

True, I could, though I don't see why I would.I want the experiment to show one of the two following possibilities: The left side would require further deposition to create a curved layer over the stone, the right side would not.Edited by Faith, : No reason given.