Clues From the Past

In general, when people think of fossils, they think of bones – especially dinosaur bones. But, fossils are not just bones, but also soft body parts and trace fossils too. Trace fossils are called ichnofossils. The most obvious type of trace fossils are footprints of vertebrate animals like dinosaurs, but there are also many other kinds of trace fossils, like burrows, trilobite tracks, fossil nests, and even fossilized dung.

Ichnofossils have to be preserved very rapidly because most are impressions of some kind, often made by very small creatures like crickets. This is an important evidence for the world wide flood. We find a lot of tracks and burrows in flood layers because animals and people were trying to get away from the flood, either through running or hiding. Also, most ichnofossils are preserved when impressions are made in fine-grained sand, and then rapidly buried in a different type of sediment (usually coarse grained).

Ichnofossils are more than just marks in the rock – they are clues from the past about how those layers were laid down, who was on top of them, and when they were made. But, clues don’t really speak for themselves, rather, you have to have a detective investigating the clues and coming to logical conclusions about what happened based on those clues and whatever information you had beforehand. Just like I mentioned last week, you are the judge, you have to come to a conclusion on your own that you are responsible for, and ichnofossils are some of your clues. We will look into ichnofossils in greater depth over the next few weeks in this Clue Series.