|This is part four of a six-part series examining supposed evidences for a global flood that have recently appeared on the Answers in Genesis web site.|
|The people at AiG are my brothers and sisters in Christ, and I share their love for the Lord Jesus Christ, their respect for the Bible as the Word of God, and their desire to see people come to faith in Christ. However, I view their arguments for a young Earth and geological catastrophism as unnecessary Biblically, poor apologetics, and a serious obstacle to the evangelism of scientists.|
|Unfortunately, few people in our churches or Christian education system have the geological background to critically analyze these arguments. The result is that people read articles like these from AiG, find them to be rather impressive, and believe that these present sound arguments in defense of the Bible. The opposite, however, is true. A vast majority of Christian geologists find the arguments for a young-Earth and the geologic work of the Flood to be untenable. It is my strong opinion that the young-Earth arguments of organizations like AiG have no place in our churches and Christian education system.|
|Part one examined the young-Earth creationist (YEC) argument that fossils at high elevations are proof of a global flood.|
|Part two examined the YEC argument that sedimentary rocks that contain dense accumulations of fossils can best be described by the action of Noah’s Flood.
|Part three examined the YEC perception that transcontinental rock layers, such as the sandstone layer that is found at the base of the Paleozoic sediments throughout much of North America, can best be explained by Noah’s flood.
“Flood evidence number four” from Answers in Genesis is called “Sand Transported Cross Country.” In this article, young-Earth creationist Dr. Andrew Snelling attempts to show that the only possible explanation for long-distance transport of sediment grains is by means of a global flood. In reality, standard geological explanations for trans-continental transport of sand grains work just fine, and there are numerous problems with the young-Earth creationist “flood geology” attempts to explain this aspect of geological history.
As you read what I have to say, remember that the Bible does not say that the sedimentary rock record was deposited by Noah’s flood. This inference is dogma in young-Earth circles, but is not found in the Bible.
Snelling begins by giving what I believe is an accurate description of several sandstone layers in the southwestern United States. Sand grains for the Coconino Sandstone and Supai Group in the Grand Canyon clearly came from a considerable distance. These layers are both underlain by extensive layers of shale or limestone that contain little sand, and cannot be the source rocks for the quartz sand grains.
As a third example of long-distance sand grain transport, Snelling cites the Navajo Sandstone, which is younger than the layers of the Grand Canyon. The Navajo Sandstone is interpreted by most geologists to be the remains of a vast terrrestrial sand dune field, and makes up some of the spectacular cliffs and other rock formations places like Zion and Canyonlands national parks in Utah.
In regards to the Navajo Sandstone, Snelling states:
“Within this sandstone, we find grains of the mineral zircon, which is relatively easy to trace to its source because zircon usually contains radioactive uranium. By “dating” these zircon grains, using the uranium-lead (U-Pb) radioactive method, it has been postulated that the sand grains in the Navajo Sandstone came from the Appalachians of Pennsylvania and New York, and from former mountains further north in Canada. If this is true, the sand grains were transported about 1,250 miles (2012 km) right across North America.”
This is good and pretty non-controversial so far, but it goes downhill from here. Snelling continues:
“This “discovery” poses somewhat of a dilemma for conventional uniformitarian (slow-and-gradual) geologists, because no known sediment transport system is capable of carrying sand across the entire North American continent during the required millions of years. It must have been water over an area even bigger than the continent. All they can do is postulate that some unknown transcontinental river system must have done the job. But even in their scientific belief system of earth history, it is impossible for such a river to have persisted for millions of years.”
Oh my. I read this and started shaking my head. It is not at all difficult to visualize a river system that is capable of carrying sand thousands of miles over a very long period of time. Where do the quartz and zircon grains eroded from the northern Rocky Mountains in Montana end up? In the Gulf of Mexico, thousands of kilometers away. Or think of sand grains being transported in other major river systems, such as the Nile or Amazon. These rivers are capable of transporting enormous quantities of sediments over time. The standard geological understanding of the Mississippi River system is that it has been in existence since some time in the early to mid Tertiary Period, perhaps originating during the Eocene Epoch (34-56 million years ago). It is not inconceivable that river systems flowing from the Appalachians at the time of Navajo Sandstone deposition (Triassic-Jurassic) could also have maintained their basic drainage patterns for tens of millions of years.
“Yet the evidence is overwhelming that the water was flowing in one direction. More than half a million measurements have been collected from 15,615 North American localities, recording water current direction indicators throughout the geologic record. The evidence indicates that water moved sediments across the entire continent, from the east and northeast to the west and southwest throughout the so-called Paleozoic. This general pattern continued on up into the Mesozoic, when the Navajo Sandstone was deposited. How could water be flowing across the North American continent consistently for hundreds of millions of years? Absolutely impossible!”
Yes, there was a consistent direction of water flow in the center of the North American continent throughout much (though not all) of the Paleozoic Era, from the Appalachian Mountains westward over the continent. This makes a lot of sense; rivers do tend to flow from mountains to lowlands (the Appalachians had been formed by the earlier collision of the North American plate with Europe and Africa). The standard geological explanation for long-distance sediment transport, rather than being “absolutely impossible” makes a lot of sense.
Snelling then makes a radical leap:
“The only logical and viable explanation is the global cataclysmic Genesis Flood. Only the water currents of a global ocean, lasting a few months, could have transported such huge volumes of sediments right across the North American continent to deposit the thick strata sequences which blanket the continent.”
I have shown that long-distance sediment transport is not a problem from the conventional geological interpretations of these rock units. On the other hand, there are a number of problems with explaining rock layers such as the Navajo Sandstone by means of a global, catastrophic flood:
- The problem of erosion — The volume of the Navajo Sandstone is about 40,000 cubic kilometers. In order to produce this much quartz sand, a considerably larger volume of granitic rocks would have had to have been eroded. If the sediments were eroded from the rocks of the pre-flood world, then erosion of several tens of thousands of cubic kilometers of granitic rocks would be necessary at the beginning of the flood. Even with a global flood, this is a tremendous amount of erosion of resistant rocks in a very short time.
- The problem of mineralogy– After erosion, some type of mineralogical sorting process would have had to occurred to separate quartz from the other components of granite, such as feldspar and mica. The Navajo Sandstone is a clean sandstone, meaning that it is composed largely of quartz grains. The zircons discussed in the article are present in low concentrations, and other minerals (feldspars, micas) have low abundances as well. Once the granitic rocks that were the source for the Navajo were eroded, some process would have had to sort out the non-quartz/zircon grains.
- The problem of sediment transport — If eroded from igneous rocks in the Appalachians, the flood would have had to somehow keep those sand grains together as a coherent package as they were transported across the continent. This is a major problem for young-Earth creationist flood geology. Floods tend to disperse sediments rather than keeping them together. The idea that the flood picked up 40,000 km3 of sand from the Appalachians and deposited it all together in the Southwest would be like saying that the sediments of the Yellowstone River in Montana stay together without mixing as they are transported down the Missouri and Mississippi Rivers and then get deposited all together in the same place in the Mississippi Delta. Fluvial transport of sediments simply doesn’t work that way.
- The problem of depositional environments — For a number of reasons, geologists interpret the Navajo Sandstone as having formed in a vast sand dune environment, similar in many ways to the modern Sahara Desert. Evidence includes types of sedimentary structures that match modern sand dune environments (dunes, ripples, and so forth) and fossil evidence (see below).
- The problem of body fossils — the Navajo Sandstone contains few body fossils, such as bones or shells. Most of what is found are either terrestrial (e.g. reptiles and mammal-like reptiles) or invertebrates that could be interpreted as living in fresh or brackish water environments rather than marine. There are also a few isolated examples of stromatolites, which are mound-like fossils of bacterial mats. These form in high salinity environments that are protected from browsers, such as in inter-dune saline flats (sabkhas) or protected areas along the shoreline. If the Navajo was deposited in the flood, why are there no clearly marine fossils mixed in? How did fossils like stromatolites get transported and preserved in the chaotic waters of the flood?
- The problem of trace fossils — Trace fossils are signs of living organisms such as footprints and burrows. Trace fossils found within the Navajo Sandstone include vertebrate footprints (what were they doing wandering around on the dry surface of the Earth half way through the flood?) and a variety of invertebrate features such as worm burrows, scorpion tracks, and spider tracks. These all indicate a terrestrial environment.
- The problem of current directions — The situation is more complicated than Snelling indicates in his article. Flow directions can be determined from sedimentary structures in the rocks, such as ripple marks. Paleocurrents for the Navajo Sandstone are primarily from the north. Sediments were apparently carried by streams flowing from east to west from the Appalachians to what is now the northern Rocky Mountains. Sea and wind currents then carried the Navajo sediments south along the western coast of the United States. At times in the Paleozoic and Mesozoic, North American paleocurrent patterns were much more complex than Snelling indicates.
- As with most young-Earth attempts to describe the geological history of the Earth, the problem boils down to “too many events, too little time.” While all of this was going on for the Navajo Sandstone, a thousand other sedimentary rock layers were being formed, magma was being intruded, volcanoes were formed and eroded, and numerous other geological events occurred, all in a one-year period. To quote Snelling: “Absolutely impossible!”
My conclusion is that the standard geological interpretation for long-distance sediment transport works, and the young-Earth flood geology interpretation doesn’t. Because it does not work, flood geology is anti-apologetics rather than apologetics. To use these sorts of arguments in defense of the Bible may bring some to faith in Christ, but it will drive others away.
Up next: Flood Evidence #5: Rapid or no erosion between strata.
With love for the body of Christ.
9 thoughts on “Six bad arguments from Answers in Genesis (Part 4)”
Regarding the Navaho sandstone, I ran across this booklet online that has some interesting details. What struck me was it gave a possible explanation for red sandstone rocks I’ve seen around here (NY) with white patches in them. Also it talks about the iron concretions in the sandstone – evidently this was written before the Mars rovers found the “blueberries”, which sound like the same type of thing.
Click to access pi-77.pdf
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Looks like Snelling has an extremely strong argument here. If the Navajo formation covers thousands of square miles and is hundreds of feet thick, and is essentually PURE sandstone that came from one source area, how could that concievably have been transported across the continent in a Mississippi River basin type fashon and be deposited in such a pure state? A sand grain from the Rocky Mountains will be deposited in the Gulf of Mexico along with tons of sediment that is not from the Rock Mountians. It is inconcievable that you would find an pure desposit hundreds of feet thick and thousands of square miles in arial extent in the Gulf that is made exclusively from material originating in the rockies. Also, it would seem that a sandstone deposit with the kind of LARGE depositional cross-bedding features seen in the Navaho would require a very energetic depositional environment operating the entire time that the formation was being deposited. The energetic depositional environment would have to extend over essentially the entire arial extent of the depost simultaneously – if it were river deposited we would find erosional channels being cut in the previously laid beds as the river shifted around and kept depositing the sand in different areas of the deposit as the deposit built up over time.
Wow, that IS good evidence for a global flood.
Thanks for your comment.
I agree that large-scale cross-stratification would be a common type of sedimentary structure formed in something like a world-wide flood as advocated by the young-Earth creationists. In fact, it should be a dominant feature of the sedimentary rock record if the flood geologists are correct.
I disagree with your assessment of Snelling’s work for the following reasons:
–The large-scale cross-bedding of the Navajo Sandstone is a good match to modern dune environments.
–As I stated, paleontological evidence works strongly against the flood geology explanation. This evidence includes reptile tracks and terrestrial invertebrate tracks and burrows.
–Perhaps the modern Mississippi isn’t the best analogy because it has three primary source areas for sediments. Sediments deposited in the Mississippi delta today come from the Rocky Mountains, Appalachians, and the upper Midwest. Paleogeographic reconstructions of the Triassic/Jurassic for the United States presents a simpler fluvial system, with streams carrying sediments from the Appalachians westward across North America. The only sand-sized grains that would survive this transport would be those with high resistance to both chemical and physical weathering, such as quartz and zircon. It is not at all difficult to visualize a combination of fluvial transport, beach transport (longshore drift), and wind transport working together to create a large dune field such as what exists in the Namib Desert along the South Atlantic coast of Africa.
–You said something about finding erosional channels being cut into the Navajo sands if it had been deposited by rivers. The inferred depositional environment of the Navajo Sandstone is sand dunes along an arid coastline. The sand was carried to the coast by rivers, but the rivers did not create the sand dunes, so we would not expect to find large stream channels. What we do find is interdune salt flats (sabkhas), which would be difficult to explain in the YEC flood scenario.
My conclusions are still that long-distance transport of sediments is not a problem for standard geological interpretations, and that the YEC interpretation of units such as the Navajo Sandstone has significant problems.
Thank you friend for confirming that you are in agreement with Snelling’s data.
1. You wrote that he gives an “accurate description of several sandstone layers in the southwestern United States. Sand grains for the Coconino Sandstone and Supai Group in the Grand Canyon clearly came from a considerable distance.”
2. And that, “Yes, there was a consistent direction of water flow in the center of the North American continent….”
First and foremost the coconino sandstone has “an average thickness of 315 feet (96 m), covers an area of at least 200,000 square miles (518,000 km2), and thus contains at least 10,000 cubic miles (41,700 km3) of sand.” Snelling http://www.answersingenesis.org/articles/am/v3/n4/sand-transported
1.The Nile River Delta is a triangle roughly 100 miles north and south with 150 miles of coastline. Even if this was a square(and it is not–you are talking 15000 miles^2,
The Cocanino sandstone is by comparison 200,000 miles^2 –conservatively 20 times larger.
2. There should be large evidence of silt and a mixture of biologically decomposed sediment to show sedimentation over time and signs of slow continental drainage over millions of years.
The sandstone is quartz sand with no similarity to that of river silt or deltas.
3. There is no sign of standard geology’s story of an ancient river system.
Let’s see the data of this river system that would have transported the vast amounts of relatively pure quartz sand.
Please include this with the above entry. Concerning comments made by Mark–entry #4,”evidence [against flood model] includes reptile tracks and terrestrial invertebrate tracks and burrows.”
Please refer to Dr Leonard Brand’s work of Loma Linda University in California. http://www.answersingenesis.org/creation/v15/i1/flood.asp Look at “Those Footprints” section.
Just one excerpt “His careful analysis…revealed that all but one had to have been made by animals moving up cross bed slopes. Furthermore, these tracks often show that the animals were moving in one direction while their feet were pointing in a different direction. It would appear that the animals were walking in a current of water, not air. Other trackways start or stop abruptly, with no sign that the animals’ missing tracks were covered by some disturbance such as shifting sediments. It appears that these animals simply swam away from the sediment.”
Thanks for your comments.
Yes, several of the young-Earth geologists (e.g. Snelling, Austin, Wise) make accurate geological descriptions. This is a significant improvement over the situation in young-Earth creationism a couple decades ago.
I don’t think you make a strong argument with your three points in comment #5.
1. You are comparing apples with oranges. If the Coconino SS is aeolian (windblown) as mainstream geologists maintain, then it is improper to compare it to a deltaic environment such as the Nile delta. It would be better to compare it to a coastal dune environment, such as the Namib desert of southwestern Africa. The Namib dune field is smaller than the Coconino, but larger than the Nile delta. Or one could use the sand seas (ergs) of the Sahara or Arabian deserts as a model, and these are comparable in size to the Coconino.
2. Again, the pure quartz sand of the Coconono is similar to what is found in sand dunes, not to what is found in fluvial or deltaic environments. Geologists say that the sand was transported from the Appalachians by streams, and then along the coast, but ultimately deposited by wind. We should not expect to find appreciable clay, silt, or organic material in the Coconino if it is composed of aolian deposits.
3. Geologists acknowledge that the river system is not preserved. It is an inference that could be wrong. That does not mean that Snelling is right; I have outlined a number of significant problems with his interpretation.
I don’t think Brand, Snelling, or Austin make a good case for the vertebrate tracks in the Coconino SS being formed under water rather than on subaerial dune surfaces. They present some interesting lab work on footprints; it would be good to look for rebuttals to this before making a judgment one way or the other. My problem is not in what they present, but in what they overlook. In the article by Snelling and Austin that you had a link to, they discuss the formation of sand waves under water (this is covered in undergraduate-level sedimentology courses). They conclude that the cross-bedding in the Coconino SS could have been formed in water 90 m deep moving at 0.95 to 1.65 m/s. I won’t argue about their numbers on this. But the problem is the formation of footprints in these sorts of conditions. What in the world were little lizards doing wandering around under 90 meters of water, in water moving over 1 m/s, in conditions of heavy sedimentation? How did they keep their feet on the sand? And what would the chances be for preservation of their footprints in these conditions?
Thanks for thinking about these things and for commenting.
No comment from Steve?
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