ETA: If Percy feels that we are getting off topic I am not going to pursue this any further.
I realize that I'm not Percy and I don't intend to spend much time myself with Faith's amazing nonsense, but I will say that if her nonsense motivates people to post educational things about Tennessee Geology as is currently happening (I'm in Tennessee), then I'm getting my moneys worth.
Faith's objections could be useful examples for you and I encourage her participation, but if discussions begin to develop around them then they should be taken to other threads.
I'm going to rule that questioning the basic tenets of geology, such as that tectonic forces and continental motions produce mountains, is on-topic because it would be very helpful to the thread's topic.
But I'm going to rule that asking what are the basic tenets of geology, such as how mountains are built, is off-topic. In this case you've participated in many threads where the process of mountain building has been described, and whether you agree with it or not it makes no sense to pretend ignorance of it.
Re: How do you get a mountain out of a slab of rock
In Message 806 I requested that there be no replies to the message, yet you're responding to it anyway. Do you somehow believe that using the general reply button makes it okay?
Questioning "how mountains are built" is not something I've done either that I know of. On this thread a few posts up, however, I did say this:
Now tell us where the mountains came from when all there is on the surface of the earth is the slab of rock from the previous time period, that as far as we can tell stayed a slab of rock until recent time ...
That is, when all you have is a slab of rock, which would have been the case with any of the strata that extend across the entire continent before the next "time period" came along, and when the slab stayed a slab, which they all did until recent time, there is no source of mountain building to be had. And if there are no mountains there is no landscape, there is only the slab of rock. I believe this topic is within the allowable subjects.
Are you saying that this is what YEC's believe happened? If so then yes, indubitably, it is on-topic. But if you're saying that this is what you think geology believes happened, then no, it isn't what geology believes happened, and if you want to argue this point then you'll have to take it to another thread.
Re: A Picture Book For Faith. See Spot Run. Run Spot, Run.
First you complain that Dr Adequate didn't explain how the strata form when he did, then when he points out that he *did* explain how the strata form you next complain that his example didn't address your scenario about continent spanning strata when it was intended to address your concerns about mountain formation and erosion and the strata that form from that erosion. This complaining just to complain isn't helpful. You also seem unaware that the principles Dr Adequate illustrated apply equally well to seas whose sediments eventually become part of continents.
Your participation in this thread could be very helpful if you brought up your objections and concerns in the context of the topic, which is about an earth science curriculum for receptive YECs. Full blown discussions of your favorite ideas don't really fit here.
About continent spanning strata, strata really only span the region of a homogenous depositional environment, which isn't static but can move around (for example, a coastline (which can represent as many as three adjacent homogenous depositional environments: sand, shale and limestone) will move back and forth as sea levels rise and fall). A stratigraphic layer could span a continent, but one wouldn't expect it to be common. For example, the Kaibab limestone spans several western states, but it's actual deposition was not simultaneous across the region. The Kaibab was deposited offshore from a coastline that shifted back and forth across the region as sea levels rose and fell. But the important point is that there is no requirement or expectation that strata should span continents.
I'm sure there are lots of legitimate challenges that you could raise. For example, if a shale sedimentary layer is miles and miles in extent in all directions, then doesn't that mean it could only have formed as a result of a single transgression or regression? But if that's true then why do people keep talking about multiple transgressions and regressions? Wouldn't multiple transgressions and regressions result in alternating sand, shale and possibly limestone layers, and not in a thick shale layer?
Re: A Picture Book For Faith. See Spot Run. Run Spot, Run.
So when a shale layer is great in extent it implies an underlying wide continental shelf, such as the one off our east coast?
The continental runoff suspended in the water that makes up shale deposits doesn't just disappear at the edge of the continental shelf, where the depth increases rapidly. What do deep water shale deposits look like?
That's a good diagram to return to. What I was originally wondering when I replied to Edge was how a shale layer of great extent could result from transgressing/regressing seas. I was imagining that that would produce a shale layer pattern like this (showing just the shale layer):
But Edge pointed out that shale deposits can occur hundreds of miles from shore so that not only do you get the pattern above, you also get a thick shale layer of great extent, as shown in this diagram with the tongues of shale and sandstone intertwined at the left margin of the Marcos Shale:
Repeating what I said last month, please, let's stop the off-topic jabber and nitpicking. This thread is for defining an educational curriculum, not for discussing the particulars in detail. Just post information, suggestions, corrections, additions, etc. To discuss anything in detail, please propose new threads over at Proposed New Topics.
Repeating what I said all those years ago, er, I mean hours ago, as in yesterday, this thread is for defining an educational curriculum, not for discussing the particulars in detail. Just post information, suggestions, corrections, additions, etc. To discuss anything in detail, please propose new threads over at Proposed New Topics.
The points recently made seem like great starting points for new discussions, so I really do wish someone would propose a new thread or threads over at Proposed New Topics.
But if I find I have to post this note again tomorrow I'll begin handing out short "just trying to get your attention" suspensions.
Precipitation and sedimentation are two different things. Precipitation is the result of a chemical reaction. Sedimentation is when solids suspended in a liquid fall out of suspension. The only way they're related is that after solids precipitate out of a solution via chemical reaction, those solids are then suspended in the liquid, and they will over time fall out of suspension, but they are called precipitates, not sediments.
There's an experiment anyone can perform that's been described to you many times. Take a few tablespoons of dirt and stir them into a large glass of water, then let it sit. While being stirred the dirt will remain suspended in the active and energetic water. Once the stirring stops there is no longer sufficient energy to maintain the larger particles in suspension and they will fall to the bottom, the larger first. Over time smaller and smaller particles will fall of suspension. The end result will be the dirt sorted by particle size, with the largest particles on the bottom and the smallest on the top.
It would be very unlikely for there to be no chemical reactions taking place in our dirt, but certainly not anything particularly noteworthy. There wouldn't be any expectation of noticeable precipitates.
In other words, the Earth's sedimentary layers consist primarily of sediments, not precipitates.