Closing In On the K-T Boundary of Dinosaur Extinction


Closing in on the K-T boundary.

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Evolutionary scientists for three decades have debated about the asteroid hypothesis of dinosaur extinction. Even those evolutionists who subscribe to the popular asteroid idea have difficulty explaining the lack of dinosaur fossils immediately below the K-T boundary. A dinosaur fossil found in Montana’s Hell Creek Formation by Yale paleontologist Tyler Lyson just 13 cm below the boundary is “the closest bone to the boundary” yet found.

The Cretaceous-Tertiary (K-T) boundary is thought by asteroid proponents to contain sediment deposited after an asteroid’s impact. The gap between dinosaur fossils and the boundary suggests to other evolutionists that the dinosaurs were extinct long before the asteroid collision. But Lyson says, “Here we have a specimen that basically goes right up to the boundary, indicating that at least some dinosaurs were doing fine.”

Numerous causes for dinosaur extinction have been proposed. Some have suggested gradual extinction. Others argue for a catastrophic cause. Worldwide atmospheric dust blocking sunlight in the aftermath of asteroid collision is one such scenario. Widespread volcanism is another suggested scenario that could have blocked sunlight needed to maintain the food supply for herbivores.

The K-T boundary marks a so-called “mass extinction event.” Fossils of many species are virtually absent in layers above the boundary. Not only do dinosaur fossils end at the K-T boundary, but also fossils of many plants and marine reptiles. The evolutionary timescale suggests the K-T boundary extinction occurred 65 million years ago.

When the asteroid extinction hypothesis was first proposed, the nearest dinosaur fossils were 3 meters (over 9 feet) below. Since that depth represented 100,000 years on the evolutionary timescale, it seemed dinosaurs were long dead before the fateful asteroid left its crater in the Yucatan Peninsula. About two decades ago, dinosaur fossils were found at 60 cm and 37 cm below the boundary. This latest find is the closest to date.

Many evolutionary scientists disagree with Lyson’s interpretation of the find as strong support for the asteroid hypothesis. “Sadly, it is only one bone,” says soil scientist Gregory Retallack, pointing out that gradual extinction would have allowed a few dinosaur bones near the boundary. Biologist J. David Archibald adds, “Finding one fragment of dinosaur [does not] suddenly make this gap go away; . .&nsp;. the gap is real.”

Proponents of the asteroid hypothesis believe a layer of iridium at the K-T boundary came from the asteroid and spread all over the world. Evolutionary geologists believe the iridium came from space because they believe any iridium on earth should have sunk in our molten planet millions of years before the K-T layer was formed.

There is, however, too much iridium to attribute to the asteroid. The dust from asteroid impact would not spread very far. Volcanoes, on the other hand, produce iridium and do tend spread their dust clouds worldwide.

As the Flood waters rose, animals would have naturally sought higher ground. Footprints, often in patterns typical of uphill climbing, memorialize many animals’ final efforts to flee the rising waters. Ultimately, even the larger dinosaurs were overwhelmed and buried.

So how do creation scientists explain the disappearance of dinosaurs from the fossil record above the Cretaceous layer? Global Flood geology explains the fossil layers in the geologic column. Many dinosaur footprints and body fossils are found in and below the Cretaceous layer. As the Flood waters rose, animals would have naturally sought higher ground. Footprints, often in patterns typical of uphill climbing, memorialize many animals’ final efforts to flee the rising waters. Ultimately, even the larger dinosaurs were overwhelmed and buried.

Rock layers above the Cretaceous are consistent with findings expected in the waning half of the Flood year and the post-Flood time. Fossils there include mammals and birds as well as reptiles and amphibians. These mobile animals would have been the last ones overwhelmed and buried.

And what of the iridium deposits? Since widespread volcanism would have been associated with the Flood, Flood geology also explains the iridium deposition and explains it better than the asteroid hypothesis does.

Thus, even though dinosaur discoveries are closing in on the K-T boundary, evolutionary scientists disagree on their interpretation of the facts. The evidence is consistent with the biblical Flood model. The catastrophic cause of mass extinction of most of the dinosaur population was the global Flood. Those descended from the ones which got off the Ark eventually succumbed to the same sorts of pressures which cause extinction in animal populations today.

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