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Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
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Author | Topic: Continuation of Flood Discussion | |||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Thinking more about Walther's Law, not clear how the sediments deposit. As the water rises onto the land are the sediments precipitating out or what?
Also it seems they are all being deposited at the same time in their respective locations -- sand, mud, silt, carbonates, foram ooze -- rather than sequentially. At least the horizontal sequence is. Is this correct? This being the case how do we get different depositional environments? And if this model does apply to the Geological Column, how do we get the great separation in age from one sediment to another? I realize this has to have something to do with the difference between the lateral deposition and the vertical that develops as the sea level rises but I can't figure it out. RAZD's Message 39 is very helpful for picturing the model in relation to the Grand Canyon sequence of rocks, but I'm unable to see how we get different time periods from this model. Edited by Faith, : No reason given.
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Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Seems to me that gnudging should have had more effects on the strata of the Silurian/Devonian/Carboniferous level than seems to be the case in the GC area at least, and I don't know why that area should be an exception when you've got continents gnudging each other.
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Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Since you don't believe in the Flood you don't have to make it fit what we see today, you can just pronounce it impossible and forget about it. But obviously I can't stop where you stop. And besides I think my scenario is more feasible than yours. No way to test it, is there? Edited by Faith, : No reason given.
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
Your first bullet is pretty much mine too, the rain eroding the land down to solid rock, sediments as you say heading to lower elevations. I called that solid rock "bedrock" which started some kind of fuss with edge which never made any sense. I see on that old thread that roxrkool called it bedrock too. I guess it's only if I use a word that there's a problem. I haven’t researched it, but to me bedrock is more of an engineering term, something solid enough to build something heavy on. A term you hear more in geology is basement rock":
quote: Edge and roxrkool are experienced working geologist. I’m a much less experienced, not working geologist.
But I don't see the huge rivers you see. More likely thousands of small rivers or rivulets flowing off hills in a sea of mud that slides down in masses and sheets. So I don't see the delta buildup you see, or the formation of river valleys. I didn’t mention the upstream flow, but that is what would get the sediment down to the large rivers. It is really speculation, of what the water/sediment load ratio would be. I was visualizing more towards the water carrying a lot of sediment, but I’m sure that in at least some situations it would be flat out mud flow. Either would get the sediment moving down gradient, but I see the less dense and viscous flow as moving all the sediment better. The denser and viscous mud flow would leave more lag deposits behind, especially in lower gradient (less steep) areas. In other words, where things got less steep, the mud would pile up. But while the solids would stop, some of the water would continue moving. And remember, it’s raining really hard everywhere, so more water is always being added.
Soon rising sea and soaked sediments meet and mingle in a thick soup over the denuded bedrock. This is the ocean so we have tides and waves and currents to move things around. Now you’re (more or less) talking waves reworking a mass of sediments with grain sizes ranging from clay to boulders. The boulders would stay in place, and the finer sediments would disperse, the gravels close, the sand further away, the silt further away, and the clays even further away. You’d have the distribution shown in the various Walther’s Law diagrams that have been posted. But you’re not going to get limestone, which is of biogenic origin.
Here's where I figure Walther's Law might enter, as the water is rising over the land, starting the process of building up strata on the naked bedrock according to those sorting principles. That process could start later though, not sure what all has to be taken into account. Basically correct. But Walther’s Law isn’t really that of a sorting process. It’s a geometric description of what you get when depositional environments shift. Which I guess is sort of splitting hairs.
One way or the other the sediments are redeposited on the land mass in layers by the end of the Flood Three miles deep at least. So when the water recedes and erodes some of it away there's so much of it, and it's already so compacted in the lower layers, the erosion is far from scouring it down to bedrock again. But I think that the reworks sediments would form a relatively thin veneer on top of a much thicker heterogeneous clay/silt/sand/gravel/boulder horizon. And we don’t have enough sediment available to be eroded (my the way things are today scenario) to form widespread miles thick layers. Besides, you’d only get a single transgressive/regressive sequence, not the multiple that we can see in the geologic records (geologic column). And you wouldn’t get limestones or other biogenic deposits. And there’s always the problem of all the deposits that are not of marine origin, mixed in there in your geologic column.
Since you don't believe in the Flood you don't have to make it fit what we see today, you can just pronounce it impossible and forget about it. We just created a what the results of the flood would be scenario. And it doesn’t match up with what we actually see. This is part of why we say The Flood never happened.
But obviously I can't stop where you stop. And besides I think my scenario is more feasible than yours. You are not troubled by the fact that your feasibility scenario totally clashes with those of people who have done a lot of schooling and field work, studying geologic processes and their results? That’s kind of like if I (geologist) went a told a renowned brain surgeon that he didn’t know what he was doing.
No way to test it, is there? A lot of processes can be seen out in the field, and be modeled in the lab, even if we can’t perform an experiment on the world wide scale. Moose ps - To the real geologists - Feel free to correct me where I went wrong.
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0
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Thinking more about Walther's Law, not clear how the sediments deposit. As the water rises onto the land are the sediments precipitating out or what? Mud, silt, and sand are clastic sediments. They are fragments of pre-existing rocks. They are sorted because the coarser clasts settle out faster/closer to land, and the finer clasts get further from land. That's the short version. Limestones (carbonates) and foram oozes are of biogenic origin. The forams settle out of the water above, while the limestone is created more in place. Much of the limestone "critter product" is reworked by further biogenic actions ("critters chewing on other critter's shells"). Limestone come in a number a varieties, which I'm not going to get into here. That's also the short version. Part of the reason you get limestone, is because the clastic sediments are not making it out that far from shore.
Also it seems they are all being deposited at the same time in their respective locations -- sand, mud, silt, carbonates, foram ooze -- rather than sequentially. At least the horizontal sequence is. Is this correct? Correct. All are being deposited on the sea floor of the time. That Walther's Law diagram just up-thread is a good thing to look at closely. But remember, it is a diagram, an approximate illustration of reality. Reality is that the contacts between the different rock types are probably more gradational, both laterally and vertically. Also be aware that in geologic cross section diagrams, there is often an exaggeration in the vertical scale. What is shown as sloping is probably actually quite close to horizontal in the real world. This vertical exaggeration also makes things thicker than reality. This is done to enable showing feature detail that would be otherwise lost. Moose
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Percy Member Posts: 22504 From: New Hampshire Joined: Member Rating: 4.9 |
Faith writes: The point I was making about the Claron had nothing to do with its elevation, the point was that it was deposited at the TOP of the stack of strata of all the "time periods" before it [--"on top of" those beneath it, even if there were once layers above it]. That was my point about the whole Geologic Column, that it IS found as a STACK, which is what makes it a model for ascending time periods and evolution of life, so that if it is now supposedly continuing to deposit at the bottom of the sea... You're describing two different locations. The Claron is one location, one stack of sedimentary layers. The bottom of the sea is a different location, a different stack of sedimentary layers.
... it is no longer a continuous stack,... Well, it both is and isn't a continuous stack, because even if they were once a continuous stack of layers stretching across a broad region, different parts of the stack will experience different tectonic forces. Consider this flat stack of layers:
_______________________________________________ _______________________________________________ _______________________________________________ _______________________________________________ _______________________________________________ And then one side uplifts and the other subsides to produce this:
____________________ ____________________\ ____________________\\ ____________________\\\ ____________________\\\\ \\\\\ \\\\\ \\\\\____________________ \\\\____________________ \\\____________________ \\____________________ \____________________ The forces of weathering erode the uplifted side, and the eroded material is carried by wind, rain, rivers and streams to the subsided side, forming additional layers:
____________________ ==> eroded material ____________________\\\ ____________________\\\\ \\\\\______________________ \\\\\_____________________ \\\\\____________________ \\\\____________________ \\\____________________ \\____________________ \____________________ ...and it certainly is no longer accumulating fossils in the line of evolution. It most certainly is "accumulating fossils in the line of evolution." As the eroded materials forms sediments in the subsided region, deceased life will become buried and gradually fossilize. --Percy
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Percy Member Posts: 22504 From: New Hampshire Joined: Member Rating: 4.9 |
Let's address the last part first:
Faith writes: ABE: "Environments" enter the picture with the fossil contents of the rock. No. A sedimentary layer representing a past environment does not have to contain fossils.
Someone back there asked how I can reject the idea of stacked environments though accepting Walther's Law. All I can say is I don't see environments in the layers described by that model, just sediments that get laid down in a particular order. Consider this diagram again:
Sand is deposited immediately offshore in a sand environment such as a beach. It lithifies to sandstone. "Siliciclastic muds" are deposited further offshore in an environment consisting mostly of the runoff from land. It lithifies to sandstone, mudstone, siltstone and shale. "Carbonate sediments" are deposited far offshore in an environment of warm quiet seas and microscopic creatures whose skeletons comprise the vast majority of the layers. It lithifies to limestone. The material in sedimentary layers comes from the environments in which those layers were deposited. --Percy
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JonF Member (Idle past 197 days) Posts: 6174 Joined: |
This being the case how do we get different depositional environments? One location will experience different environments as it rises and falls, travels around the globe, and external factors (such as overall sea level) change.
And if this model does apply to the Geological Column, how do we get the great separation in age from one sediment to another? Various ways.One common one is that layers A B C D E deposit in that order over a long time, then the environment changes from depositional to erosional (maybe the land raises like the Colorado Platequ), layers E D C erode away in that order, then the environment changes back to depositional and layers F G H deposit in that order. Big age separation between layers B F because of the missing C D E layers. You really need to learn to think in terms of millions of years, even though you don't believe it's real, to understand geology. Edited by JonF, : No reason given.
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Percy Member Posts: 22504 From: New Hampshire Joined: Member Rating: 4.9 |
Faith writes: The deposition of any of those sediments doesn't necessarily take time although their formation may, and even there probably nowhere near as long as OE thinking assumes. There is no such thing as OE thinking, only evidence-based thinking. There's nothing particularly appealing about the concept of an ancient Earth other than that all the evidence says the Earth is ancient. We assume nothing. The processes we observe today depositing sedimentary layers are very slow. At a rate of say 4 cm/year it would take 40,000 years for a sedimentary layer to accumulate to a depth of a mile. Also, radiometric dating confirms that the layers are ancient and mostly formed slowly. The tiny particle size comprising the sedimentary layers require that they formed slowly, because it takes a great deal of time for tiny particles to fall out of suspension in even quiet water.
Beach sand is not created on the beach, it's created by tossing in the water and then it's deposited on the beach. I should have provided more detail about how beach sand is produced. Beach sand is produced by weathering forces, mostly on land. The forces of weathering carry eroded material to the lowest point, usually lakes and seas. The most energetic water exists at the interface between land and water in the form of waves. Only the larger and denser materials from land can deposit in an energetic environment, which would be sand. The smaller and lighter particulates are carried further out from shore and are deposited as siliciclastic muds. --Percy
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New Cat's Eye Inactive Member |
Seems to me that gnudging should have had more effects on the strata of the Silurian/Devonian/Carboniferous level than seems to be the case in the GC area at least, and I don't know why that area should be an exception when you've got continents gnudging each other. As the layers above them build up, they get more and more pressure on them, which smushes them down and flattens and hardens them.
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edge Member (Idle past 1735 days) Posts: 4696 From: Colorado, USA Joined: |
The point I was making about the Claron had nothing to do with its elevation, the point was that it was deposited at the TOP of the stack of strata of all the "time periods" before it ... That was my point about the whole Geologic Column, that it IS found as a STACK, ...
Yes, the geological column is shown as a 'stack', at each location on the earth where we find it. Each 'stack' is different depending on the location and its particular geological history. As one location is underwater, others are undergoing erosion, others are are deserts and some are swamps. It' not all that hard to understand.
... which is what makes it a model for ascending time periods and evolution of life, so that if it is now supposedly continuing to deposit at the bottom of the sea it is no longer a continuous stack, and it certainly is no longer accumulating fossils in the line of evolution.
No, the 'stacking' simply continues elsewhere as erosion occurs at the Grand Canyon. Sedimentation does not need to be continuous at any one location or at all locations as you seem to think.
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edge Member (Idle past 1735 days) Posts: 4696 From: Colorado, USA Joined: |
Mud, silt, and sand are clastic sediments. They are fragments of pre-existing rocks. They are sorted because the coarser clasts settle out faster/closer to land, and the finer clasts get further from land. That's the short version.
These are good points. I'd like to add that I sometimes think of carbonates, such as the Chalk of western Europe as being somehow 'isolated' from siliciclastic contamination. Limestones (carbonates) and foram oozes are of biogenic origin. The forams settle out of the water above, while the limestone is created more in place. Much of the limestone "critter product" is reworked by further biogenic actions ("critters chewing on other critter's shells"). Limestone come in a number a varieties, which I'm not going to get into here. That's also the short version. Part of the reason you get limestone, is because the clastic sediments are not making it out that far from shore. Edited by edge, : No reason given. Edited by edge, : No reason given.
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edge Member (Idle past 1735 days) Posts: 4696 From: Colorado, USA Joined: |
I didn’t mention the upstream flow, but that is what would get the sediment down to the large rivers. It is really speculation, of what the water/sediment load ratio would be. I was visualizing more towards the water carrying a lot of sediment, but I’m sure that in at least some situations it would be flat out mud flow. Either would get the sediment moving down gradient, but I see the less dense and viscous flow as moving all the sediment better. The denser and viscous mud flow would leave more lag deposits behind, especially in lower gradient (less steep) areas.
Just to be clear, a lag deposit is what is left behind after the winnowing of sediments, leaving behind larger or heavier fragments. However, yes, the mudflows tend to leave behind some very interesting deposits, such as those filling valleys around Mount Saint Helens. As they flowed down the stream channels they eventually encountered more water flow and became more diluted until they formed a thin layer of light colored silt in the Columbia River delta. Different conditions in different environments, but all from the same process.
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edge Member (Idle past 1735 days) Posts: 4696 From: Colorado, USA Joined: |
Seems to me that gnudging should have had more effects on the strata of the Silurian/Devonian/Carboniferous level than seems to be the case in the GC area at least, and I don't know why that area should be an exception when you've got continents gnudging each other.
Can you give us some geological principle that says all locations must undergo tectonism or erosion or volcanism within a given time period?
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edge Member (Idle past 1735 days) Posts: 4696 From: Colorado, USA Joined: |
Sand is deposited immediately offshore in a sand environment such as a beach. It lithifies to sandstone.
I think we should focus more on the two schematic stratigraphic columns at the bottom of the diagram. What you see are two locations with different columns, both occurring at the same time; and each showing more than one depositional environment. "Siliciclastic muds" are deposited further offshore in an environment consisting mostly of the runoff from land. It lithifies to sandstone, mudstone, siltstone and shale. "Carbonate sediments" are deposited far offshore in an environment of warm quiet seas and microscopic creatures whose skeletons comprise the vast majority of the layers. It lithifies to limestone. The material in sedimentary layers comes from the environments in which those layers were deposited. In fact, the diagram shows a correlation line between the two columns showing how we compare two different sequences. Now, carry that back in time over dozens of sections and you will start to get a complete picture of the regional geological history. Obviously this diagram is a simplification of the process, but it is a real task done by stratigraphers around the world.
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