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Author Topic:   Young earth explanations for Angular Unconformities
bdfoster
Member (Idle past 3260 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 25 of 202 (418341)
08-27-2007 4:03 PM
Reply to: Message 21 by The Matt
08-27-2007 9:22 AM


Re: compelled to reply
This is true. Uplift and deformation can happen surprisingly quickly in geologic terms, especially in tectonicly active areas like southern California. Of course happening in the flood year is laughable. The Saugus Formation in the northern L. A. basin is the Pleio-Pleistocene deposits of the ancient Santa Clara river. The deposits are not associated with the modern drainage but with an ancestral, much larger river. The youngest of these deposits are only about 500,000 years old, but they are deformed to very steep inclinations along the San Gabriel fault. I don't know if there is any formal unit that overlies the Saugus, but the Saugus itself overlies older units with angular unconformity. I can't find the specific reference I was looking for, but that's the basic story. The rates of uplift and deformation are crazy here in So. Cal. especially near the faults.


Brent

This message is a reply to:
 Message 21 by The Matt, posted 08-27-2007 9:22 AM The Matt has not yet responded

  
bdfoster
Member (Idle past 3260 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 50 of 202 (420324)
09-07-2007 12:51 PM
Reply to: Message 49 by Adminnemooseus
09-06-2007 1:03 AM


They're everywhere
Here's a couple of angular unconformities. Not really spectacular "text book" examples. But it just goes to show they're everywhere. Not just one or two flukes.

In the first one, from northern California, the lower steeply inclined unit is Cretaceous Great Valley sequence. It's hard to see the bedding in the upper unit but it is flat. The unit is the Pliocene Tehama Formation. There's A couple of notable features: first, a fault in the lower right of the picture with drag folds that indicate the direction of movement. The hanging wall (upper block) has moved up. The fault doesn't appear to extend into the Tehama although there may have been an erosional scarp. Also, at the base of the flat lying Tehama is a "basal conglomerate" that includes eroded material from the lower unit. It clearly indicates the lower unit was solid rock before the upper unit was deposited.

In the second one, from southern California, I'm not sure what the units are. The lower one is probably a marine sandstone, part of the Tertiary section that is common in this area. the upper unit is probably a very old stream terrace (old for a stream terrace, probably Pleistocene) deposit associated with a river that is about 200 feet downslope, or perhaps not associated with any modern drainage. The thing to note about this one is that the upper unit is composed mostly of sandstone boulders derived from the lower unit, and granitic boulders from the local mountains. Most stream terraces are adjacent to the stream they are associated with. So I think this unit may have been deposited by an ancestral river that is no longer reflected in the modern landscape. It is a mysterious enigmatic unit, and it may have formed in a "catastrophic" flood. But one thing is certain: it formed much later than the sandstones that it covers. And whatever flood formed it was not global. The extent of this unit is confined to this particular valley. Whatever flood, or more likely floods, that formed it didn't even cover the local drainage divides.


Brent

This message is a reply to:
 Message 49 by Adminnemooseus, posted 09-06-2007 1:03 AM Adminnemooseus has not yet responded

Replies to this message:
 Message 51 by Ihategod, posted 09-09-2007 11:21 AM bdfoster has responded

  
bdfoster
Member (Idle past 3260 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 53 of 202 (420956)
09-10-2007 12:26 PM
Reply to: Message 51 by Ihategod
09-09-2007 11:21 AM


Re: They're everywhere
I'm not sure what the significance of being near the surface is. An erosion surface is the main feature of all unconformities. Erosion surfaces form at the earth's surface so I'm not sure why this would be a problem. Nevertheless, in the first photo the upper unit, the Tehama Formation, thickens eastward from this location to about 2000 feet in the middle of the Sacramento Valley. The unconformity, with Great Valley sequence overlain by either the Tehama or other formations, is traceable in the subsurface in oil and gas wells throughout the valley. Numerous unconformities, most of them not angular occur above this major angular unconformity in the subsurface of the Great Valley. Subsurface erosion surfaces can even be mapped, showing typical surface features like weathering and stream channels. An ancient impact crater has been found in the subsurface of the Great Valley.

In the lower picture, yes the upper unit is quite young. I called it a very old terrace because it is elevated a couple hundred feet above the modern drainage. Young modern terraces are right next to the modern channels. This is one of the youngest deposits in the area. But it is in the road cut so it must pre-date the road. And a close look at the deposit indicates it was not formed in a single event. Some of the deposit consists of unsorted material ranging in size from boulders to sand. Some boulders not well rounded and are in a sandy matrix with no preferred orientation.This suggests deposition by debris flow. But other parts have gravel that is well rounded and sorted, suggestimg normal channel deposition. There are even sandy lenses that look like sand bars. The upper material does indeed appear to have been depositged rapidly, but clearly not in one event. Rapid deposition like this does not go against the basic principles of geology, it is in perfect accord with them. There is no problem finding modern analogs for this type of deposit.

The geologic mechanisms used to explain these unconformities are totally incompatible with flood geology. In the early days of geology, unconformities like these could not be explained by the geologic mechanisms of 18th century catastrophism. It was recognized that after deposition, the deformed sediments had to have been tilted, uplifted and eroded prior to the deposition of the upper sediment. The overlying units often contain eroded and weathered pieces of the underlying units, as well as material derived from rocks that did not esist when the upper rocks were deposited. In the Sierra Nevada granitic rock intrudes older deformed meta-sedimentary rock. Both are truncated by an erosion surface and overlain by younger Tertiary sediment. The Tertiary sediment contains material from the tilted meta-sediment and the granitics that intrude them. What flood geology mechanism could explain this? Remember it has to explain the presence of lithified, weathered pieces of underlying rocks and pieces igneous rock that has intruded (and therefore must be younger) the underlying rock. You've got one year to do it! Noah's flood year. Mainstream geology has all the time in the world.

Edited by bdfoster, : No reason given.


Brent

This message is a reply to:
 Message 51 by Ihategod, posted 09-09-2007 11:21 AM Ihategod has not yet responded

  
bdfoster
Member (Idle past 3260 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 56 of 202 (421185)
09-11-2007 12:40 PM
Reply to: Message 55 by The Matt
09-11-2007 3:26 AM


Re: They're everywhere
I'm now fairly sure that you haven't understood any of the basic principles in the slightest.
Explain how you think each of these are violated.

It may be that Vashgun is saying, angular conformities were formed in the deluge. They have horizontal sediment overlyling tilted sediment. Therefore superposition and original horizontality must be false. If they were true it would violate his logical premise, that angular conformities were formed in the deluge.


Brent

This message is a reply to:
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Replies to this message:
 Message 57 by jar, posted 09-11-2007 12:48 PM bdfoster has not yet responded
 Message 58 by Ihategod, posted 09-12-2007 6:40 PM bdfoster has responded

  
bdfoster
Member (Idle past 3260 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 61 of 202 (421605)
09-13-2007 11:23 AM
Reply to: Message 58 by Ihategod
09-12-2007 6:40 PM


Re: They're everywhere
Im not saying throw the los and lot out, it just looks like those principles don't apply to unconformities. The only thing that violates my logical premise, is your saying there is a dichotomy between the laws and what my eyeballs are seeing.

But we've been over this. It's impossible for LOS not to apply. To suggest that there is any chance at all that a sediment is older than the surface on which it is deposited is like saying the sun didn't rise today. Original horizontality is indeed an assumption that is made in the interpretation of angular unconformities. In the upper picture I posted it is assumed that that the inclined sediments were not originally deposited with such a steep inclination. That's a reasonable assumption. It is consistant with the way modern sediments are observed to be deposited. To assume otherwise, that the sediments were originally deposited at their present inclination, betrays an unwillingness to accept the obvious and proper interpretation of angualar unconformities: that flood geology is absolutely impossible.

BTW to suggest that honest responsible geologists, some who happen to be Christians, twist the obvious and interpret angular unconformities the way young earthers suggest, is beyond unconscionable. Christians should not be involved in this kind of intelectual dishonesty.

Edited by bdfoster, : No reason given.

Edited by bdfoster, : No reason given.


Brent

This message is a reply to:
 Message 58 by Ihategod, posted 09-12-2007 6:40 PM Ihategod has responded

Replies to this message:
 Message 62 by Ihategod, posted 09-16-2007 3:07 AM bdfoster has not yet responded

  
bdfoster
Member (Idle past 3260 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


(1)
Message 78 of 202 (423862)
09-24-2007 4:59 PM
Reply to: Message 73 by CTD
09-24-2007 8:40 AM


I can't believe this thread.

CTD writes:

I just don't see these things as a problem for YEC flood models. Unless one assumes that all geology has to be accounted for by a single flood.

All YEC flood models have a substantial part of the sedimentary record resulting from the deluge. It's the only event in biblical history that could even conceivably produce the vast accumulations of sedimentary rock on the planet in the time frame allowed by biblical literalism. Some flood models have the pre-flood and post-flood boundaries at different places. For example some say that Precambrian sediments are pre-flood. Some say that Tertiary sediments are post-flood. But the facts of the geoligic column, a history written in God's own hand, won't allow anything this simple. Vast thicknesses of sediment occur in both Precambrian and Tertiary systems. If the pre-flood boundary is taken to be at the Precambrian/Paleozoic boundary, then all Precambrian sedimentation, which amount to thousands of feet in some basins, must have occurred by normal non-catastrophic means. The same problem exists for the vast thicknesses of Tertiary sediments. Having large parts of the geologic column not deposited by the flood creates as many problems as it solves. If a global flood is needed to explain much of the geologic column, what explains the rest? But the farther removed are the upper and lower boundaries of the flood, the more features the flood has to explain. Everything stratigraphically contained by the flood deposits must be accounted for by the flood. Things like unconformities, paleosols, vast accumulations (thousands of feet thick and millions of cubic feet) of flood basalts, vast accumulations of evaporites, vast accumulations of deep water limestone and chert, vast accumulations of lake varves, surfaces that have clearly been exposed to air (with mudcracks, footprints of air-breathers) etc. Any one of these can occur at the base of the flood, but there are countless examples of them stratigraphicly contained in the sedimentary record.

In the seventeenth and eighteenth centuries before much geology was known, flood geology was understandably much more acceptible. But with the discovery of the geologic features mentioned above it became impossible to keep flood geology as a paradigm. Flood geology is absolutely falsified by these geologic features.

CTD writes:

But just for example, what's wrong with an unconformity being at the grand canyon if prior to the flood there were rocks of one type, and then more were deposited on top of them? I really don't see a problem with this, and it seems to be the favorite. I believe the model I'm thinking of for the newer formations is Walter Brown's.

I read Walt Brown's book "In the Beginning". Two of the bald faced lies I remember were that there are no magnetic reversals on the sea floor, and there are no meteorites in the geologic record. We could probably do a whole thread on each of those claims. But for now, the statements are wrong, they are matters of fact and not opinion, and Walt Brown, with a PhD in mechanical engineering should know better. He has an elaborate theory for the flood. I think he calls on the flood to account for the fossiliferous deposits (post-Precambrian). He calls for liquefaction to account for faunal succession (the regular arrangement of fossils). Once again, as an engineer he should know this is impossible. Liquefaction only occurs in sand and some silt. Liars like Walt Brown and ministries like ICR and AIG that push 18th century geology are an embarrassment to Christianity.

Edited by bdfoster, : No reason given.

Edited by bdfoster, : No reason given.

Edited by bdfoster, : No reason given.


Brent

This message is a reply to:
 Message 73 by CTD, posted 09-24-2007 8:40 AM CTD has responded

Replies to this message:
 Message 79 by CTD, posted 09-25-2007 1:28 AM bdfoster has responded

  
bdfoster
Member (Idle past 3260 days)
Posts: 60
From: Riverside, CA
Joined: 05-09-2007


Message 82 of 202 (424071)
09-25-2007 12:46 PM
Reply to: Message 79 by CTD
09-25-2007 1:28 AM


CTD writes:

One of the main features of Walter Browns model is a subsequent flood in the Grand Canyon area which would take place when trapped waters burst free. I have personally played with water and mud dams, and the shapes of the formations match up very well with my results.

This type of flooding is documented in the geologic record. It caused the features now seen in the Channeled Scablands area of eastern Washington. Not exactly the incised meanders and differential erosion seen in the Grand Canyon. The Grand Canyon could not have been eroded in soft sediment as this model requires. The Grand Canyon has vertical cliffs in sandstone and gentle slopes in the shales, like most natural landscapes. But this is the opposite of what is seen in unconsloidated sediment. Anyone familiar with construction sites will know you can't dig a trench in wet sand. Wet sand won't hold a face for 5 minutes much less 5,000 years. Wet clay OTH has cohesion, and will hold a vertical face.

CTD writes:

I'm not aware of the meteorite issue, but I know about the pole reversal thing. There's no need to call anyone a liar for not believing in them. The evidence is slim, and subject to interpretation. And there's no reasonable mechanism which would cause such an event.

Magnetic pole reversals are one of the most solidly established phenomena of historical geology. They were known to occur on land long before they were discovered on the sea floor. Remnant magnetism in rocks has been known since the time of the Curries. Pole reversals were found to occur in vertical sequences of rock. The initial discovery of reversals on the sea floor resulted from aerial magnetometer surveys. These surveys measured the total magnetic field of an area. Because the remnant magnetism in rocks is very small, and it has to pass through the ocean and the atmosphere to reach the plane's instrument, the remnant magnetism is swamped by the earth's magnetic field. So the areas of reversal corresponded to areas where the measured magnetic field was slightly less than average. These were interpretted to be reversals. Walt'Brown mentions that the reversals were inferred from aerial surveys. Most people probably don't know this, and it shows he has researched it. But he doesn't mention that the reversals have been confirmed by thousands of oriented drill cores from the Ocean Drilling Project and the Deep Sea Drilling Projects. The fact of pole reversals is well established. The cause of the reversals is a completely different issue. But the fact that rocks of different age have different geomagnetic orientation is indisputable. Entire fields of study have sprung up around paleomagnetism and magnetic stratigraphy.

Brown's meteorite thing was that in a billions of year old geologic column you would expect countless meteorite impacts. But there are no known meteorites from the geologic record, therefore it must be relatively young. Well first of all meteorites are one of the rarest commodities on the planet. There are only about 25,000 authenticated meteorites that have ever been found. The British Museum of Natural History catalogues them. It is incredibly rare to find a meteorite if no one saw it fall. They look much like any other rock. Even finding a meteorite on the surface of the earth is a rare thing, and Walt Brown wants us to find them in a random vertical slice through the geologic column?!?! And yet they have been found in spite of what Brown says. Numerous large impact structures are known in the geologic record. Chicxulub is just one. They are all studied extensively by research teams that live for finding out everything there is to know about impacts. Scores of hapless grad students spend hours examining cores and looking for little pieces of meteorite, and then publish the results.

Don't get me wrong I would never call someone a liar for being misled by Brown's book. But there's no excuse for people like Brown.

Edited by bdfoster, : No reason given.

Edited by bdfoster, : No reason given.


Brent

This message is a reply to:
 Message 79 by CTD, posted 09-25-2007 1:28 AM CTD has not yet responded

  
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