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Author Topic:   Continuation of Flood Discussion
RAZD
Member (Idle past 1404 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 46 of 1304 (731304)
04-29-2014 5:28 PM


Re: So just HOW does this model apply to the GC?
Thank you for laying that out, it's very helpful for visualizing what the model is all about. The lateral extensions are where the model is seen to be consistent, not the vertical stack.
Thanks, I probably spent too much time on it, but I wanted to see how it worked out.
I think you may have inadvertently included the Hermit Shale in your revised version of the Coconino Sandstone, however.
Edge Message 42 said it was terrestrial (I originally had it as mud and the coccino as sand), and I figure he is the expert here (I'm no geologist per se just a dabbler).

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edge
Member (Idle past 1705 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 47 of 1304 (731305)
04-30-2014 2:15 AM


Re: So just HOW does this model apply to the GC?
I think so too. The interesting thing is that, if the Hermit Shale were slid to the left, there would be an obvious discontinuity. We'd see deep water deposition "suddenly" (in geologic terms) change to aeolian deposition. So between the Hermit and Coconino would be an obvious place to look for evidence of "intermediate" layers that transitioned between deep and shallow water but are no longer there because of erosion. Or maybe evidence of a "sudden" uplift or something.
Typically, I read red beds as indicative of continental deposits.
Siltstone beds are dark red and crumbly, and fill shallow erosion channels that are widespread. Siltstone beds form recesses between thicker sandstone beds; locally contains poorly preserved plant fossils in channel fills in lower part of formation. Sandstone beds thicken and thin laterally either as channel fill or low sand dune accumulations.
USGS URL Resolution Error Page
Note the existence of channel fill and plant fossils. Discontinuous sand lenses commonly locate stream channels. There is also the suggestion of dunes, I believe in the upper part of the formation.
All these things suggest that the Hermit was deposited above sea level, containing numerous erosional surfaces as streams cut through a swampy area or coastal plain, likely very close to the sea.
As regression continued, eolian sands innundated the swampy lowland and formed a coastal erg (Coconino Sandstone) similar to the Namib Desert.
Edited by edge, : No reason given.

  
Faith 
Suspended Member (Idle past 1444 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 48 of 1304 (731306)
04-30-2014 4:48 AM


How does aerial deposition make such a flat layer?
As regression continued, eolian sands innundated the swampy lowland and formed a coastal erg (Coconino Sandstone) similar to the Namib Desert.
The problem I always have with the idea that the Coconino was deposited aerially is that it's so flat and straight on the bottom and the top. I have two pictures of it on my computer that I can't get to post here, which drives me crazy, but they show the extremely sharp tight contact lines, one of them between the Coconino and the Toroweap above, which I find extremely hard to explain if the Coconino is supposed to have been actual dunes before the deposition of the layer on top of it; and the other shows the similarly straight tight contact line between the Coconino and the Hermit beneath it. If "eolian sands innundated the swampy lowland" to deposit the Coconino on top of the Hermit shale, and formed anything that looks like the Namib desert on top of a "swampy lowland," how could there have been such a neat straight flat contact? That is what we expect to see from water deposition such as this model of rising and falling seas illustrates.
I know the Coconino has a crossbedding at an angle of repose that suggests it has to have been formed aerially, but this seems to me to be more than contradicted by its extreme flatness.
This link ought to go to a picture of the
Coconino sandstone that shows its straightness and flatness.
Here, This link ought to go to a collection of pitures of the Coconino, one of which shows it submerged in water and the tight contact between it and the Toroweap above.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.

  
Faith 
Suspended Member (Idle past 1444 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 49 of 1304 (731307)
04-30-2014 5:17 AM


Rox's post on related things
I just want to put here a link to the post that Moose just nominated for a Post of the Month, by roxrkool, which is certainly a very thorough and interesting post that could maybe be included in the discussion here in some way. She posted that diagram there that we are talking about. At the time it was too much for me to think about, too technical and detailed in the context, but now I'm beginning to get it so this could be a good reference to keep on the table.
Just have to comment here that the comparison she shows between the extent of the sandstone in the geologic column and the sand dunes in Africa assumes that such dunes could become strata like the Coconino sandstone, which I don't find at all likely, which is pretty much what I'm saying in the post above this one too.
On that other thread I was objecting to the idea of a gigantic rock pancake's representing a Time Period, and there are certainly more gigantic ones than the Navajo Sandstone, such as the Redwall Limestone that traverses the whole continent. In any case, my objection now is to the idea that a huge area of sand dunes could ever become a gigantic rock pancake.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.

  
petrophysics1
Inactive Member


Message 50 of 1304 (731308)
04-30-2014 6:21 AM


No scientific methodology
I know the Coconino has a crossbedding at an angle of repose that suggests it has to have been formed aerially, but this seems to me to be more than contradicted by its extreme flatness.
This link ought to go to a picture of the
Coconino sandstone that shows its straightness and flatness.
Ever measured the Coconino?
Ever measured sections through it from bottom to top where you describe it in detail? You know it's grain size, sorting, mineral content, color, cross bedding, flow direction, depositional dip, thickness etc. and their variations across an area.
Ever map it and all it's variations?
I've asked you five times to explain your procedure for determining the depositional environment of rocks. You do not have one, but somehow determined a flood deposited this, and that IS a depositional environment.
I concluded you looked at post cards and dreamed up about anything you wanted even if it violated well know physical and chemical laws. You measure nothing, you collect no data and so you think everything is interpretation. The concept of data forcing a conclusion on you is something you know nothing about since you know nothing about gathering geologic data.
I noticed you linked a picture in your quote above. As I said that is the sum total of your geologic methodology. That is not how it's done.
Here is what people who actually looked at the Coconino have to say:
Coconino Sandstone (Lower Permian)Tan to white, cliff-forming, fine-grained, wellsorted, cross-bedded quartz sandstone. Contains large-scale, high-angle, planar cross-bedded sandstone sets that average about 35 ft (11 m) thick. Locally includes poorly preserved fossil tracks and low-relief wind ripple marks on crossbedded planar sandstone surfaces. Lower 5—20 ft (2—6 m) is intertongued, thinbedded, partly calcareous, flat-bedded sandstone of Seligman Member of Toroweap Formation. Unconformable contact with underlying Hermit Formation is sharp planar, with relief generally less than 3 ft (1 m) but locally as much as 8 ft (2.5 m). Desiccation cracks in the Hermit, as much as 2 ft (0.05 m) wide and 12 ft (4 m) deep, are filled with tan sandstone of the Toroweap or Coconino, mainly in eastern third of map area. Thickness of the Coconino decreases east to west, whereas Brady Canyon and Seligman Members of Toroweap Formation increase proportionally in thickness. Forms a 500-ft (154-
m) thick cliff in southeast corner of map area, thinning northward to about 350 ft (122 m) and westward to about 150 ft (45 m) at western edge of map area.
USGS URL Resolution Error Page
The observations above blow your flood idea out of the water.

  
edge
Member (Idle past 1705 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 51 of 1304 (731309)
04-30-2014 9:56 AM


Re: How does aerial deposition make such a flat layer?
quote:
The problem I always have with the idea that the Coconino was deposited aerially is that it's so flat and straight on the bottom ...
No one here has suggested that the Hermit represents a terrain of anything other than low relief and that the actual contact is an unconformity. I would expect that contact to be sharp, relatively flat (even though it is not completely so, as you indicate) and extensive.
ETA: Mud cracks in the top of the Hermit that are filled with sand from the overlying Coconino are kind of hard to explain any other way.
quote:
... and the top. I have two pictures of it on my computer that I can't get to post here, which drives me crazy, but they show the extremely sharp tight contact lines, one of them between the Coconino and the Toroweap above, which I find extremely hard to explain if the Coconino is supposed to have been actual dunes before the deposition of the layer on top of it;
The top of the Coconino grades upward and laterally (Walter's Law) into the lower member of the Toroweap, so the upper contact is not as sharp as you might think, though weathering accentuates the change. This is transition back toward a marine environment as the Coconino submerged. I have no problem with a beach or intertidal zone planing off the tops of any sand dunes that remained from the Coconino deposition.
quote:
and the other shows the similarly straight tight contact line between the Coconino and the Hermit beneath it. If "eolian sands innundated the swampy lowland" to deposit the Coconino on top of the Hermit shale, and formed anything that looks like the Namib desert on top of a "swampy lowland," how could there have been such a neat straight flat contact?
See above.
quote:
That is what we expect to see from water deposition such as this model of rising and falling seas illustrates.
And yet the evidence says otherwise.
quote:
I know the Coconino has a crossbedding at an angle of repose that suggests it has to have been formed aerially, but this seems to me to be more than contradicted by its extreme flatness.
On a regional scale, I'd say it's not all that flat and uniform.
quote:
This link ought to go to a picture of the
Coconino sandstone that shows its straightness and flatness. Here, This link ought to go to a collection of pitures of the Coconino, one of which shows it submerged in water and the tight contact between it and the Toroweap abov
I don't see anything in these photos that contradicts an eolian environment. In fact, while the formational boundaries are concordant, it is pretty clear that there is local erosion between the Toroweap and the Coconino where cross beds in the Coconino are cut by the contact. The Toroweap is transgressing over the Coconino and planing off internal textures.
Edited by edge, : No reason given.

  
edge
Member (Idle past 1705 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 52 of 1304 (731310)
04-30-2014 2:01 PM


Re: Rox's post on related things
Just have to comment here that the comparison she shows between the extent of the sandstone in the geologic column and the sand dunes in Africa assumes that such dunes could become strata like the Coconino sandstone, which I don't find at all likely, ...
Based on what?
On that other thread I was objecting to the idea of a gigantic rock pancake's representing a Time Period, ...
Why is that?
... and there are certainly more gigantic ones than the Navajo Sandstone, such as the Redwall Limestone that traverses the whole continent.
Really? Then perhaps you can point out the Redwall or its equivalent in New York state.
In any case, my objection now is to the idea that a huge area of sand dunes could ever become a gigantic rock pancake.
Why is that?
I think what you are telling us is that you simply cannot believe certain things based on limited knowledge and a religious framework.

  
Faith 
Suspended Member (Idle past 1444 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 53 of 1304 (731311)
04-30-2014 3:25 PM


Re: Rox's post on related things
Seems to me that to turn sand dunes into a flat rock, and it IS flat and straight to the naked eye, couldn't happen by new sediments covering them over -- they would simply fall over the dunes into the valleys. Even wet sediment would do that although it might have some flattening effect, just not the VERY flattening effect that had to happen to produce the straight contact lines that are visible to the naked eye. Of course if you submerge the dunes they might flatten out some too, but then you wouldn't have that angle of repose that determines aerial deposition any more -- OR the actual flatness that exists. And you need pressure from above. You need a flattening of the sand and pressure from above. If the sand deposited in swamps how is any resultant sandstone going to be flat on the bottom? If another sediment deposits on the dry sand how is it going to be flat on the top? Seems pretty straightforward to me, but of course you're the Geologist and you just know it had to happen the way you say it happened whether it makes sense or not.
I can find the video if necessary, creationist video, that says the Redwall extends across the continent and even into the UK.
Edited by Faith, : No reason given.
Edited by Faith, : No reason given.

  
Taq
Member
Posts: 9970
Joined: 03-06-2009
Member Rating: 5.6


Message 54 of 1304 (731312)
04-30-2014 5:25 PM


Re: Rox's post on related things
Seems to me that to turn sand dunes into a flat rock, and it IS flat and straight to the naked eye, couldn't happen by new sediments covering them over -- they would simply fall over the dunes into the valleys.
If you cut away a real life, modern sand dune, this is what you see.
Earth & Environmental Sciences | College of Science and Engineering
Look at that. They are absolutely flat.
Edited by Taq, : Added credit for picture, which is a great website btw.

  
Coragyps
Member (Idle past 734 days)
Posts: 5553
From: Snyder, Texas, USA
Joined: 11-12-2002


Message 55 of 1304 (731313)
04-30-2014 6:56 PM


Re: How does aerial deposition make such a flat layer?
I know the Coconino has a crossbedding at an angle of repose that suggests it has to have been formed aerially...
You still haven't tried your angle of repose kit????

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 56 of 1304 (731314)
04-30-2014 6:57 PM


Re: Rox's post on related things
Well clearly that was caused by one of those global floods we've been having lately.

  
RAZD
Member (Idle past 1404 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 57 of 1304 (731315)
04-30-2014 7:03 PM


Re: Rox's post on related things
Look at that. They are absolutely flat.
The issue is the top layer of the dunes, a large wave shape on land with minor wind ripples on the surface..
Faith's hypothesis is that it would remain intact as the sea transgresses over them, when it is much more likely that the peaks are washed into the valleys by the waves. Sand is shown as the transition deposition between terrestrial and marine, and thus would have to undergo wave action as the sea rises, leaving a predominantly flattened surface with minor wave ripples.
Then as the sea transgresses further -- the process takes years -- the flattened sands would be covered by muds and then calcites.
Simple

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Taq
Member
Posts: 9970
Joined: 03-06-2009
Member Rating: 5.6


Message 58 of 1304 (731316)
04-30-2014 7:36 PM


Re: Rox's post on related things
Faith's hypothesis is that it would remain intact as the sea transgresses over them,
You mean Faith actually thinks that water will leave loose sand at such steep angles of repose? Seriously?
How about visiting any beach in the world. Look at where the sea meets the sandy beach. Notice the absolute absence of any sand dunes with 30 degrees of slope where the water is bashing up against the sand.
If Faith can't even get this simple observation right . . .

  
Faith 
Suspended Member (Idle past 1444 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 59 of 1304 (731317)
05-01-2014 1:22 AM


Re: Rox's post on related things
The crossbedding produces straight lines too, though not necessarily horizontal ones, but I'm talking about the HORIZONTAL surface of the rock that can supposedly form from sand dunes, that very flat straight surface, both top and bottom, clearly seen in pictures of the Coconino, which has nothing to do with the crossbedding but with formation of the sand into a layer that becomes sandstone. Show me how that forms, in such a way as to be just as flat and horizontal as any of the layers that are considered to have been formed inater.

  
Faith 
Suspended Member (Idle past 1444 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 60 of 1304 (731318)
05-01-2014 1:23 AM


Re: Rox's post on related things
I have NO idea what you are talking about. I've been told repeatedly that the Coconino sandstone exhibits an angle of repose that proves it formed on dry land. Period.

  
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