Long build up of Sediments

In message 19 Faith asked: This is a massively good question, and one that I don't recall ever previously encountering from a creationist. Indeed, it's rare for even the evolution side to raise that point. I was about to raise the point myself, and found that Faith had beat me to it!Now, others have covered the answer already, so I will not. But I will say that the question is not a problem in the old Earth time frame, but it certainly is in the young Earth time frame.Skipping ahead, Faith (in the message this is a reply to) says: Now, we could quibble over what is really meant by the term "geologic column", and such has been done elsewhere in earlier topics. But as Faith uses the term, "geologic column" seems to mean the entirety of the Earth's continental crust. Faith seems to think that the vertical sequences of rock of the Earth's crust are the same everywhere. This is very wrong, but again is not a detail I wish to here explore.What I will focus on it the two quoted statements. Faith asserts "The entire geologic column was formed by the flood. THAT's the beginning and end of the flood." Now, the entire so called "geologic column" is not all sedimentary rocks (a Faith flood problem in itself), but a big part of it is. So I turn Faith's own question back on her.How does Faith explain where all the sediment comes from that has piled up to such a depth? Faith is seemingly saying that the flood has reworked the entire pre-existing continental crust into what is currently the form of the continental crust. And if indeed such is the case, what was the nature of the Earth's "geologic column" prior to the flood?May have to later transplant this discussion into the Faith/Moose "Great Debate" topic, which BTW I did do a recent minor reply to recently.POTM soon coming to Faith, for that question quoted at the top of this message.Moose

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Professor, geology, Whatsamatta U
Evolution - Changes in the environment, caused by the interactions of the components of the environment. "Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham

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"The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness." - John Kenneth Galbraith

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"I know a little about a lot of things, and a lot about a few things, but I'm highly ignorant about everything." - Moose

I don't know the specific source of the cite information, but my impression is that you see mountains as being just tall stacks of more or less horizontal strata. While that might sometimes be the case (the Unita Mountains?), often mountain ranges are complex folded and faulted messes. You can have a mountain much higher than the stratagraphic thicknesses of the strata that make them up. There may also be substantial volumes of igneous intrusives in the mountain (research the term "Batholith" for more on very large igneous intrusives, including seeing http:///WebPages/Glossary_Geology.html#B).Also remember, it's not a simple case of the mountains being uplifted and then being eroded down. Erosion is already happening as the mountains are being uplifted.In northeastern Minnesota we have the remains of a very early mountain range (rocks dated at 2.7 billion years old), the area now being relatively low hills. These rocks (research topic: Ely Greenstone) have been intensely folded and faulted. Much of the strata is now vertical rather than horizontal, and there is evidence for vertical displacement by faulting of the magnitude of tens of kilometers.A specific example in northern Minnesota, is where the Ely Greenstone is in fault contact with another formation. The EG, while being heavily folded and faulted itself, is of low metamorpic grade (it has not been subjected to very high temperatures and pressures). But the formation it is in fault contact with is of high metamorphic grade (anphibolite facies). It can be determined what temperatures and presures were required to form the metamorphic minerals of the rock. Now I'm about to pull a number out of my shakey memory, but if anything, it might well be an understatement. It is thought to have once been under pressures that indicate that it was once buried 20 kilometers (c. 60,000 feet). Now it is at the surface. This means that something like 20 kilomenters of rock have been eroded off to expose this rock. Again, I'm not real certain about that 20 km figure. It might actually be more like 40 km. Is there a metamorphic petrologist out there?Geo-critiques of the above blathers welcome.Moose

I don't have the greater context of the point, but apparently Jar is trying to point out that erosion DOES NOT happen between already in place sedimentary layers - Erosion does not happen beneath the top surface of the total sediment pile.Now, erosion may happen during the time period after one strata is deposited and before the next strata is deposited. Indeed, in many cases erosion is happening at one spot, only to have the sediment immediately redeposited right close by. Think a modern river or beach. Sediment is moving around - If a particle is moved from a rest position, it is erosion; If a particle comes to rest from movement, it is deposition. Thus, in detail, many sediments may be chock full of errosional surfaces, which, of course, are the depositional surfaces of what lies above.Now a phrase along the lines of "errosion has happened between layers" might actually be used, but it is meaning that the existing sediments were eroded prior to the next sediments up being deposited.Very minor disclaimer to the above info: There are such a thing as sediment "volcanos" and sediment dikes (dykes to the British sorts). This happens when the sediments contain enough fluids to behave as a fluid (think quicksand). In such cases, sediments can be squeezed from locations below, either into the above sediments or even out onto the sediment surfaces. I think this is a very minor effect in the geologic record.Moose

Consulting the Dictionary of Geological Terms: Varieties of unconformities include:Angular unconformaty - Strata below has a different orientation than those above. Much erosion has happened.Nonconformaty - Strata is on top of older intrusive igneous rock or metamorphic rock. Much erosion has happened.Disconformity - Unconformaty between parallel strata. May be purely a non-depositional event.I talked about this upthread a bit, but...Unconformities exist in a wide range of degrees. The unconformity may be a multi-billion year gap, or it may be a few seconds gap. Indeed, if you want to look at the situation in extreme detail, the time between one sand grains deposition and the next sand grains deposition could be considered an unconformity.Now, your "sudden layer transitions" seem to be what I would file under "disconformities". It may be difficult to determine how significant of a non-deposition/erosion gap it is. It could be many years; It could be essentially zero time.Moose

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Professor, geology, Whatsamatta U
Evolution - Changes in the environment, caused by the interactions of the components of the environment. "Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham

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"The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness." - John Kenneth Galbraith

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"I know a little about a lot of things, and a lot about a few things, but I'm highly ignorant about everything." - Moose