-After our discussion, I was excited to learn as much as possible about the other sand dune formations found around the world. I quickly realized that the formation and movement of sand dunes are not as obvious as they might appear to the untrained eye. For example, the Barchan Dunes, which are found all around the world, appear to be shaped by water (at least, I thought they did). Thanks to the "Historical Imagery" tool though, I learned that these sand formations are moved fairly quickly by wind.
As I dug deeper into the various dune fields, I learned that there really hasn't been that much research done on them. Imagine that! Not too many people are eager to wander out into the middle of a lifeless desert to study how sand moves... Another thing that stood out to me is that most of the sand dune formation research was done nearly 100 years ago, by one man. His work still forms the foundation of modern science in this field. He never had access to satellite data though.
We are the first generation that has easy access to our entire planet, thanks to Google Earth. Using this tool, along with the Historical Imagery, we can understand how our planet changes over time.
In one of the research papers linked above, the scientists admit that the sand dunes found in the Scablands of Eastern Washington were created during the ice age floods, roughly 12,800 - 10,000 years ago. This sand is likely the remains of some mountain ranges up north, which were eroded as the Cordilleran Ice Sheet was catastrophically melting.
Based on this understanding, I began to look at our sand dunes around the world. The Nebraska Sand Hills, which are the largest dune field in the Western Hemisphere, have been dated to 12,600 years ago. That was the oldest sediment date found in the sand dunes. If that dating is accurate, it coincides almost perfectly with the initial meltdown of the Laurentide Ice Sheet. Therefore, the formation of the Nebraska Sand Hills may be similar to the formation of the Scabland dunes. As the Laurentide Ice Sheet began melting due to some catastrophe, large flows of meltwater came pouring down south. Some of these flood waters may have washed over Nebraska, and deposited a large amount of sand. This would have all taken place during the start of the Younger Dryas.
As we know, the Younger Dryas started with a bang, and then got very cold. It remained that way for roughly 1,200 years. At ~11,600 years the Younger Dryas ended due to another large warming spike and we eventually transitioned into the present Holocene epoch. With the help of the National Map Viewer, and the "Tinted Hillshade Overlay" we can clearly see which way the flood waters went. (To the east of Nebraska). Therefore, I would say it's possible the initial event that triggered the Younger Dryas sent a pulse of meltwater down into Nebraska, depositing most of the dune field. Then, at the end of the Younger Dryas, the meltwater formed a new path through South / North Dakota and Minnesota. This became the major outlet for most of the meltwater, which is why it is so well-defined. This also explains why the Nebraska Sand Hills still exist, they were spared from most of the direct flood waters of the melting Laurentide Ice Sheet.
Assuming this hypothesis is correct, it would help to explain the formation of other dune fields found around the world. This brings us to the Catastrophism vs Uniformitarianism debate. The Uniformitarians look at our present rates of change and erosion, and apply that same speed throughout history. In other words: slow, incremental, one grain of sand at a time. The canyons we see, like the Grand Canyon, took millions of years to erode. The mountains we see, like the Rockies, took millions of years to grow.
A catastrophist sees the world through a different lens, all around him are clear signs of fast, intense erosion and deposition. The mountains may have been formed much faster, especially if a comet or asteroid slammed into the planet and accelerated the movement of plates and faults. Or at the very least disturbed them enough to become more active. This could also trigger volcanoes to erupt, continental plates to jolt and create tsunamis, and much more.
These catastrophic events could even lead to large floods, which are capable of moving large quantities of sand...