“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.

Snelling continues:

“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.