At http://westerndigs.org/oldest-known-footprints-in-north-america-identified/ … a surprisingly large number of human footprints have been preserved in sedimentary rocks in N America – going back to the Younger Dryas, or shortly before. This seems to make a lie of the idea sedimentary rock is only found over long periods of time – as some of those footprints date from little more than four or five thousand years ago. The processes that changed mud or silt into rock must still exist – and must still be taking place in the modern world. Why do geologists find so little evidence of Holocene sedimentary deposits in that case?
In addition, the discovery may seem to show that the now arid Chihuahua desert of northern Mexico, where it abuts the Texas border, was an entirely different kind of landscape in the Early Holocene. Like the Sahara desert, the Mexican desert was in fact a quite pleasant place in which to live – and humans appear to have thrived. The climate was wet, and vegetation verdant. Was a little bit of this ancient landscape buried and preserved as a result of an unknown upheaval in the natural world? Why otherwise should footprints have been preserved in fresh mud?