During the last Ice Age when the oceans were up to 300 feet lower than they are today an extensive cave system on the Yucatan Peninsula of Mexico was exposed above sea level allowing it to be inhabited by land animals. When the great ice sheets melted from the Earth’s surface causing the oceans to rise, these caves systems were drowned and are now only accessible by divers. In 2012 divers exploring one of these drowned caves systems discovered a nearly complete human skeleton on the cave floor over 3000 feet from the nearest entrance. Now pieces of that skeleton have been dated yielding an estimated age of at least 13,000 years before present. (Stinnesbeck et al. 2017)
What is particularly fascinating about these remains is the evidence that this skeleton must have come to rest in its current location well before the cave was flooded by rising sea levels. Some of the bones have stalagmites that have grown on top of them. In fact, it was by dating the age of the stalagmite that had grown on top of the bone that scientists were able to set a lower limit to the age of the bones themselves. These stalagmite must have grown from water dripping onto the bones when the cave was dry. Later, ground water filled the cave stopping stalagmite formation and preserving the remains as they appear today for many thousands of years.
What do these bones tell us about the history of human occupation of the New World? This skeleton represents one of the oldest dated human remains found in the New World. The fact that it was found in a cave that was once above sea level but is now many meters below sea level tells us that this person had entered the cave during the last Ice Age when sea levels were much lower than they are today exposing extensive cave systems that had been produced by underground rivers prior to the sea level drop. During this time when the caves were exposed many animals utilized the caves including giant sloths and other South American Ice Age animals.
A tight squeeze: When did this person live in the young-earth chronology?
Young earth creationists (YECs) believe that all people alive today are dispersed descendants of a group of people who had gathered at Babel in the Middle East about 4250 years ago (see timeline below). According to the YEC timeline of history, some of those people left Babel and migrated through Asia over the Bering Strait. This land bridge between North America and Asia had just formed during an Ice Age that began 4250 years ago. From there people migrated down into North America, Central America and eventually populated South America.
The Ice Age is said to have lasted from 4250 before present to about 4000 years before present or a total of only 250 years. There are many human remains in the New World that testify to human occupation during the most recent Ice Age. Hence, in the YEC timeline man must have migrated to North America from the Middle East and established populations across two continents in less than 250 years. In fact, the timeline below suggests that the New World wasn’t even accessible for nearly 100 years after Babel and then humans finally enter into the Americas just about 2100 years ago near the end of the Ice Age.
The evidence from the bones sitting below sea level in a cave in Mexico further highlights the absurd nature of this proposed rapid migration and population expansion. Not only does this require that this people must have migrated all the way to Central America while the oceans were much lower than they are today but this particular person had to enter the cave, die there, decompose and then stalagmites had to form on top of its bones. That whole stalagmite was dated and not only was it very old but the dates from different parts of the stalagmite indicate it took over 1000 years to grow. This time of growth had to occur while the cave was above sea level and so this person must have died in the cave well before the end of the last Ice Age because there had to be enough time for the stalagmites to form before the cave was drowned.
YECs will dispute the time it takes to form a stalagmite but even if this they may form quickly the stalagmites unequivocally show us that the bones were laid in the cave while it was dry and that some period of time was necessary for further cave formation before being drowned.
Once again, our observations of the world around us are difficult if not impossible to reconcile with the YEC chronology of earth’s history. Is it reasonable to believe that less than 200 years, one or a few families would have traveled from the Middle East up through Asia, cross into North America and then made their way down into Central America all the while splitting off group members to populate areas along the way? Why continue to leave areas that are ideal habitats to migrate across mountains, through cold and icy regions, cross rivers, and deep deserts? How could populations have expanded so quickly in just 200 to 300 years that it allowed people to find their way to almost every part of the New World before the end of the Ice Age? Constant migration wouldn’t seem to be ideal conditions for population growth especially since the world they would have encountered would have many predators at the time such as many kinds of large cats (saber-tooth cats and lions).
Normally stalagmites grow very slowly and there is nothing in this particular cave to suggest that we would expect growth any different that we observe today. The very presence of a stalagmite on top of the bones contradicts the very restricted YEC timeline of the Ice Age and human occupation of North America. All of the observations we make of human remains and cultural artifacts found in the Americas are readily accommodated by an old earth model of Earth’s history.
YEC explanations for these bone and others observations require a set of unrealistic ad-hoc proposals that stretch all reasonable bounds of rational inquiry.
I’ve written about another set of bones found in another cave in Mexico that tells a similar story: Underwater Cave Yields Fossilized Teenage from the Ice Age
Stinnesbeck W, Becker J, Hering F, Frey E, González AG, et al. (2017) The earliest settlers of Mesoamerica date back to the late Pleistocene. PLOS ONE 12(8): e0183345. https://doi.org/10.1371/journal.pone.0183345