I've been watching this film at You Tube of a talk by creationist Paul Garner about the formation of the Grand Canyon. GREAT talk. You'll never find this sort of information at EvC.
The talk is all about the evidence in the Grand Canyon for catastrophic deposition of the layers as opposed to deposition over hundreds of millions of years.
He presents a creationist division of the layers into pre-Flood, which is the Precambrian or basement rocks of the Canyon, Flood-deposited, which is the main body of the strata above that to the rim at the Kaibab Plateau, and post-Flood, which is those strata which can be seen in the Grand Staircase but no longer exist over the Grand Canyon. (I was very happy to see him affirm that the layers that constitute the Grand Staircase to the north are understood to have originally covered the Grand Canyon area as well.)
This dividing of the layers into time units is the sort of system I've always found hard to accept because I see no difference in the presentation of the layers themselves to the naked eye that would suggest any reason to attribute different mechanisms of deposition to them. But the "PreCambrian" basement rocks do present a different appearance so I can see how they can be thought of as a separate kind of deposition that pre-existed the Flood. .
He organizes his talk to address five kinds of evidence demonstrated in the canyon for its formation by the Flood of Noah:
- Fossils of marine organizsms high above sea level
- Rapid burial of fossil organisms
- Extraordinary extent of the sedimentary rock layers
- Rapid or no erosion between the layers
- Many strata deposited in rapid succession
On No. 3 He gives the evidence of the enormous horizontal extent of the different layers, the lowest Tapeats sandstone that rests on the basement unconformity, for instance, extending across the entire continent of the US and up through Canada, also being found on other continents although he doesn't give an illustration of that. Same with the Redwall Limestone, which has an enormous range across the North American continent, and he mentions that the same basic formation can be found in England as well. The Coconino sandstone covers the Southwest into Colorado and Texas, as deep as 800 feet in some places. Such a huge extent of the layers is evidence that they were not laid down by any processes known to be occurring today, which is the usual claim.
Addressing No. 4 he points out the knife-edge contact between some layers conventionally explained as unconformities which assumes there to be layers missing between them. He also discusses the erosion between the Great Unconformity and the lowest horizontal layer that rests on it, the Tapeats sandstone, as having to have been PHYSICAL erosion. He says there is no evidence of the chemical erosion of weathering that would have occurred if the lower layer had been exposed as land surface for millions of years, which is the usual theory, and he shows an embedded boulder that suggests the erosion was caused by a rapid catastrophic debris flow that "simultaneously broke up and transported blocks of the underlying precambrian rocks in a matrix of sandstone."
I've had my own theory about this boundary as the level at which the force of the underground volcano along with the tectonic force which triggered it, met the resisting weight of the more-than-two-mile depth of wet layers that were at that time all laid out above. I see this collision of forces as having formed the basement rock, including the metamorphic rock or schist and of course the granite, and the Great Unconformity itself, all confined beneath the stack above under great heat and pressure, the force being enough to uplift the stack above into its current position, cracking the uppermost layers which permitted the rushing in of the water which scoured out the canyon.
EVIDENCE that the strata were all in place when the uplift occurred is the fact that the strata conform to the curved sides of the uplift instead of butting into them, which is what would have happened if they'd been laid down at any time afterward. THEREFORE the tectonic-volcanic action that caused the uplift came after all the strata had been deposited, or at or after the end of the Flood.
The abrasion at the boundary between the basement rocks and the Tapeats layer would have been violent in the extreme, easily accounting for the kind of erosion he's talking about.
His analysis is great just as it stands, but I still like my explanation for how the canyon got cut in the first place as a result of the tectonic-volcanic uplift from beneath, which also explains how the uppermost layers got broken up and washed away, their also being the major agent of the scouring of the canyon as they went, and it's also another way of explaining the erosion between the Tapeats and the Precambrian rocks that he explains in terms of a catastrophic debris flow. His explanation has a different cause and different timing but is the same kind of violent physical action I pictured.
He observes that the bend in the whole stack of strata over the East Kaibab Monocline is evidence for their simultaneous deposition, which I've also observed in north-south diagrams of the conformation of the whole stack over the uplift. The conformation of the strata as a whole stack to any such curve is evidence for rapid deposition. So I'm showcasing this as both a great well documented thoroughly scientific presentation of the evidence for the Flood that is so nicely exhibited in the Grand Canyon, and a confirmation of some of my own ponderings on the subject. http://www.youtube.com/watch?v=5aNlb3lFhFM