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Author | Topic: Formations really do match detailed lab expts of sorting under rapid currents | ||||||||||||||||||||
edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
quote: I think you are confused about laminations, beds, formations and time. Perhaps if you took some geology courses, you wouldn't sound so silly.
quote: Here you don't seem to understand that a formation is not a time-stratigraphic unit. A formation is really just a convenient package of rocks that is useful in geological mapping. We have understood that formations can transgress time since Geology 101.
quote: Why wouldn't it be?
quote: Then show us evidence that you undstand 'this stuff'.
quote: This is just another case of 'a little knowledge being a dangerous thing.'
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
quote: Wow, I don't know where to begin!
quote: This makes no sense at all. The experiments that I am aware of simply show that sands can be laminated during high flow regimes. It says nothing about the deposition of an entire environment on the scale of a sedimentary basin. By the way, you still have to prove to me that a sand grain could be deposited before the one underneath it, or that one lamination is younger than the lamination beneath it. You are confusing relative elevation with timing here. You need to get outside the box.
quote: Once again, your statements belie you lack of training and basic understanding. You are confusing vertical position with time equivalence. This is not what superposition is all about. But then, you would know this if you had some background in the science. By the way, TB, do you really think that geologists have not recognized this feature of progradation until creationists came along to tell us about it?
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wehappyfew Inactive Member |
As I re-read some of your posts, TB, I find some more clues indicating where you are confused about some essential concepts in sedimentology.
Line-by-line, let's review:
TB writes:
We have several problems here: although the strata within the Tonto facies are sperated by bedding planes (essentially by definition)1. The Tonto group is not a "facies", it is a large accumulation of many, many facies. 2. The 3 formations within the Tonto Group are NOT seperated by bedding planes, as should be clear by now from my explanations in previous posts. 3. Your assumption that this is "essentially by definition" reveals a lack of understanding of what constitutes a formation, stratum, facies, and/or bedding plane. TB writes:
I have seen closer to 45-50 million years. Saying that the Tonto Group represents the passage of "70 million years" is an oversimplification. At any one location, the 3 formations may span something like that time interval (I haven't checked the actual data in any specific loacations), but the 70 Mya it took in western Arizona occurred earlier than the 70 Mya of depostion in southeastern Utah.
So the 70 million years traversed by the Tonto is not really true? TB writes:
Exactly. The Muav in the west is older than the Tapeats in the east. This is evident both by the law of superposition (the bedding planes are inclined), and by index fossil assemblages.
Are you saying that some of the Mauv limestone was laid before some of the Tapeat sandstone? TB writes:
Nope. The Law of Superposition remains unbroken. My fellow geologists do not assign any "gaps" to the Tonto, I believe it is considered a continuous record of tens of millions of years of deposition in any given locality. At DIFFERENT localities, the time intervals may not be contemperaneous, however.
...I can almost gaurentee you that your fellow geologists would put a near 70 million gap between those formations. You are clearly distancing yourself from the principle of superposition in this case and I applaude that. TB writes:
Just to be clear, time-transgressive sequences are being formed today. A modern prograding delta deposits at least 4 main types of sediment: Do yuo get anything like 300 foot facies of stuff forming on top of 300 foot beds on top of 300 foot beds today? 1. Freshwater meandering delta channels, oxbows, swamps, etc. 2. Nearshore sands, in the form of beach, tidal and shallow water sand waves 3. Slightly deeper water silts 4. Deep water shales (clay-sized particles) All of these are deposited simultaneously today. The top surface of the delta, beach, and offshore ocean bottom represent the top of a potential bedding plane that might be preserved in the sedimentary record. This bedding plane extends unbroken from the land out to deep sea. The sediments grade imperceptably in many cases along this bedding plane from sand to silt to shale. If you look under ground, you find that today's beach sands are being deposited on top off finer grained shallow-water sediments, and the shallow water sediments overly deeper water shales, and so on. In the past, the delta was farther inland, so going down into the ground is like going back in time (superposition again), and into a sedimentary environment formed in deeper and deeper water. This simple picture can be complicated by things like subsidence, sea-level change, sediment starvation, etc. The Mississippi River delta right now is subsiding rapidly, for example. That means river floodplain sediments are being reworked into, and overridden by, beach sands as the shoreline retreats. Most of the sediment load of the river that normally would replenish the delta is bypassing the floodplain as a result of Man's intervention.
TB writes:
What you "don't see" is a reflection of how limited your knowledge of mainstream geology is. Time-progressive formations are not a new or surprising phenomena to geologists.
If your agreeing with us on the hydrological sorting mechanism that is great but I don't see that ackowledged by the stratigraphic dating guys.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
quote: In our continuing effort to educate Tranquility Base, I submit the website below as a primer on some aspects of sedimentology. As you will see, this is not a trivial subject to be mastered by reading a few advanced papers, and some background is helpful. I would like TB to pay particular attention to Walther's Law. http://www.dc.peachnet.edu/~pgore/geology/geo102/facies.htm
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
quote: Just an added note - The prograding delta is for all practical effect the same as a regressing sea. Moose
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Tranquility Base Inactive Member |
weyhappy
You show me where there are 1000 foot deep transgressive sequences with only three facies occurring anywhere today. Sorting that would occur on the scale required for the Tonto group is the Flood. [This message has been edited by Tranquility Base, 12-06-2002]
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Tranquility Base Inactive Member |
To all of my teachers here
I enjoy learning from you but what sort of teacher pretends that his student doesn't understand something he does? In the very first post of this thread I outlined what transgressive, prograding seqeunces are all about (I summarized it in plain English for the typical reader here):
quote: That was my first post! Most of you are quite rude. I am perfectly aware that regressive seqeunces have been understood for a long time, at least as long as J. Walther of Walther's law (about 100 years ago) if not longer. But I have never, ever read that applied to an entire 1000 foot bed stratigraphically except by creationoists. And if that is the case then the only difference between us is that we would point out that 1000 vertical feet covering only 3 facies and the 800 kilometres traversing 3 prograding beds speaks of something much larger than a slow marine invasion. Austin estimates 0.5 to 2 metres/sec for about 3 days would generate the entire Tonto deposit. The vertical and horizontal scope is very different to your beaches.
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edge Member (Idle past 1736 days) Posts: 4696 From: Colorado, USA Joined: |
quote: Ummmmmmm, one that gets the impression that the student is willfully ignorant?
quote: I'm not sure what current directions have to do with it, but since you bring it up why is the transgression occurring in the opposite direction of the current flow?
quote: We have been over this. Your lab experiments do not model the entire system. You do not have silts, muds and lime deposits in the flume experiments. Why is TC not backing you up on this, by the way? Oh, maybe because his references point out this fact.
quote: "Under current..." Wow! this is pretty deep 'stuff.' This does not express any kind of understanding. Check out your current directions.
quote: Yes, the time-stratigraphic unit is the lamination, not the bed. You would understand this if you got some basic training in geology.
quote: So, have you made any progress?
quote: Most of us have a terminal case of exasperation that you completely ignore any data that contradicts your mythical scenario.
quote: Then why do you not understand that a lamination is not a bed is not a time marker.
quote: THat is because your investigation is limited. If you truly understood transgressive and regressive sequences, then you would understand this. There are plenty of examples.
quote: Three beds? Three facies? Really, where do you get this stuff?
[quote]Austin estimates 0.5 to 2 metres/sec for about 3 days would generate the entire Tonto deposit. The vertical and horizontal scope is very different to your beaches.[/B][/QUOTE] No it is not ... it is happening today. Do you not read our posts? Talk about rude! So where does Nevins get his velocities? Does he realize that this is not a flood, but a mudflow? In fact it is not possible to generate limestones under such conditions. A surge that could depoosit the Tonto group in a few days could not permit the deposition of limestone with all of that suspended clastic material. It is also impossible to get evaporites. Sorry, TB, but your lack of background in this area is exposed with every sentence you post. You are getting in deeper and deeper, so to speak. And by the way, we need to talk about your grades...
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Tranquility Base Inactive Member |
Edge
Austin's reconstruction has 800 horizontal kms from Nevada to New Mexico being laid from west to east via advancing flood waters with mostly 0.5 to 2 m/s flow velocity (W to E). From west to east we have Muav limestone, Bright Angel shale, Tapeats sandstone and the Great Unconformity. It's fine with me if you think this stuff was laid via hydrodynamic sorting vertically at the same time as horizontally.
quote: I thought we were talking about the 1000 foot Tonto series with three facies: M limestone, BA shale, T sandstone. It is these three which form a transgressive seqeunce from Nevada to NM or are we talking past each other? I apologize about referring to these also as beds. I am unaware of the exact definition of a bed and tend to use it to mean a collection of strata. But I know what a facies and a stratum are technically. Feel free to educate me on the definition of a bed. Should I refer to the Tonto as a bed or a formaiton or either? [This message has been edited by Tranquility Base, 12-06-2002]
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Tranquility Base Inactive Member |
So, since none of this is controversial to anyone then it doesn't matter to any of you that what is normally given a 70 my age difference could have been partially ocurring at the same time? That represents about 13% of the Phanezoic geo-col from the Cambrian to the Quaternary. How can you guys ever date a fossil by its position in the Cambrian in that case?
Anyway, if you're prepared to believe that 13% of the Phanezoic is partially overlapping then we will point out that at that sort of rate the pre-Cenozoic Phanezoic could have been formed in about 6 or 7 such episodes. The scale of depositon calls for flow rates that would have deposited it all in a matter of months. [This message has been edited by Tranquility Base, 12-07-2002]
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wehappyfew Inactive Member |
1000m transgressive sequences take a long time to form. Your request is nearly unreasonable. The fact that modern transgressive sequences are universally thin (often tens of meters since the LGM of 40kya) should be a clue that 1000m in five days is not feasible.
Here are some of the numerous examples of modern transgressive sequences: Woods Hole Coastal and Marine Science Center | U.S. Geological Survey"A Continuous Holocene transgressive sequence recorded in an 8-M core taken from northern Chesapeake Bay A complete sediment sequence that records the Holocene sea level rise, beginning about 8000 yr BP, is well preserved in an 8-m sediment core (RR98-9)..." "We identified three distinct lithofacies (C, RE, and OE) in core RR98-9. Lithofacies C, a basal channel deposit, is preserved in the lower 50 cm. it is a massive, dark greenish gray (SGY 4/1), moderately sorted, coarse-grained pebbly sand with common wood -fragments. These channel sands were deposited before about 7800 yr BP. Atop lithofacies c is lithofacies RE, whose base is marked by an oyster bed. Lithofacies RE is approximately 320 cm thick and is characterized by dark gray (5Y 4/1) to dark greenish gray (5GY 4/1) muddy sand to sandy mud, with scattered oyster beds J15 to 40 cm-thick) and common woody organic layers. Filled burrows are well preserved in the upper loo cm of this lithofacies. The lithology, shell and organic debris, and burrows suggest that RE was deposited in a restricted estuarine environment, probably a sand flat or tidal channel. Lithofacies RE was deposited during the interval of 7800-3740 yr BP. The youngest lithofacies preserved in this trangressive sequence, lithofacies OE, is about 410 cm thick and is composed of massive to diffusely laminated, slightly sandy (trace to 10%) clayey mud." Notice the fining upward character of the 3 facies, indicative of transgression. http://www.sci.qut.edu.au/...rch/geopsed.htm#plaeogeographicThird abstract down on the right side: "The onset of Tertiary sedimentation was marked by the deposition of a regionally widespread transgressive silisiclastic unit known as the Gobernador Formation, which was deposited under continental conditions in the south-southwest of the basin, changing to coastal marine conditions in the east-northeast. Over most of the area, this quartz-dominated sandstone unit is overlain by marine shelf mudstone, but to the north-northeast part of the study area, the Gobernador Formation passes vertically to the transgressive bioclastic limestones of the masparrito Formation." "The thickness of the Gobernador Formation varies from 12 m to 220 m..." So a transgression that spans the whole Teriary can accumulate a pretty significant thickness. http://www.gl.rhbnc.ac.uk/palaeo/2palynology.html"The Nanggulan Formation has been shown to be a transgressive sequence containing a series of stacked rising sea level sequences. These sequences may be comparable to the cycles (third order) from TA 3. 4 to TA 4. 1 or from 43. 0 Ma to 36.0 Ma. These sequences support palynological zones. The coastal plain setting (lower unit) changes upward into brackish or marginal marine, then into shallow marine (lower part of middle unit). The palaeoenvironment then shifts into deeper marine, characterised initially by gravity flow deposits and finally by deep water, fine-grained, volcanics and marls."
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Tranquility Base Inactive Member |
^ But the fact that the three facies that make up the Tonto are about 300 feet thick each but look like a transgressive sequence belies the catastrophic scale. That is the point I am trying to make. The strata can be followed horizontally despite the fact that the age of a stratum traverses much of the age of the bed! In your case a single stratum ridiculously traverses much of 70 million years. It is so obvious that these huge beds were deposited rapidly.
ah2gfwj sbswbng (my oldest son typed that and I'll leave it here for posterity) [This message has been edited by Tranquility Base, 12-07-2002]
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wehappyfew Inactive Member |
TB writes:
I think you are forgetting that the designation "Cambrian" is determined by the fossils, not the other way around.
So, since none of this is controversial to anyone then it doesn't matter to any of you that what is normally given a 70 my age difference could have been partially ocurring at the same time? That represents about 13% of the Phanezoic geo-col from the Cambrian to the Quaternary. How can you guys ever date a fossil by its position in the Cambrian in that case? The concept of time-transgressive rock formations is not new.
TB writes:
The understanding that rock units are often time-transgressive is an integral part of geology.
Anyway, if you're prepared to believe that 13% of the Phanezoic is partially overlapping then we will point out that at that sort of rate the pre-Cenozoic Phanezoic was could have been formed in about 6 or 7 such episodes. TB writes:
Ummm... no else here is buying your fantasies about rapid formation of hundreds of feet of limestone and other rocks. Chemically, it is impossible, as has been pointed out to you already. Geologically, modern anologs show precisely what is expected - the 1000meters of the Tonto Group requires a lot of time and a slow average rate of transgression. The long time scale is revealed in every detail of the rock. But your sources have carefully glossed over the details: The scale of depositon calls for flow rates that would have deposited it all in a matter of months.YEC-faslifiers such as well-sorted, well-rounded mature sands in the Tapeats and other Cambrian sandstones; extensive bioturbation, burrows, trilobite fragments and fossils; the complete and utter lack of any land animal or plant in the basal unit of the Tapeats; and many, many more. It looks like we are moving to the fingers-in-the-ears stage of the lesson plan, gents. It's about time to pack it in. Chalk up another in the list: Cyclothems, galactocentrism, helium diffusion in zircon, Paluxy mantracks, and now transgressive sequences. Did I miss any?
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Tranquility Base Inactive Member |
^ Lots of rhetoric Wehappy.
So no comment on the fact that the facies sorted hydrodynamically from each other are about 300 feet thick each?
Wehappy writes: I think you are forgetting that the designation "Cambrian" is determined by the fossils, not the other way around. Nevertheless the 70 million year difference, 13% of the Phanezoic, just became overlapping. [This message has been edited by Tranquility Base, 12-07-2002]
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mark24 Member (Idle past 5225 days) Posts: 3857 From: UK Joined: |
TB,
quote: Why, then, can I see multiple coarse flat bedded conglomerates within a foot of each other?
Mark ------------------Occam's razor is not for shaving with.
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