This post is about the recent footprints found in the dried up river bed in texas. I’m aware about carbon dating, but I thought you have to have organic material. And to add on top of that, wouldn’t the layer of earth that dates back be eroded/built upon by sediments in the river?
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ELI5 answer: Dino steps in mud, mud turns to rock and leaves footprint. Scientists find footprint and figure out who’s foot it belongs to. Based on who’s foot fits the footprint we can figure out an age.
Non ELI5 answer: Footprints like that are considered “trace fossils” as in it is a trace of the organise rather than direct evidence. Dating trace fossils is exceptionally difficult, especially so for footprints but this will depend on the material that the trace fossil is found.
By using “absolute dating” we can date the material the tracks were made in to get an idea at least of how old the rocks are. The problem with trace fossils like footprints, they are left behind in what is now a sedimentary rock and most absolute dating techniques won’t work on sedimentary rock that are that old.
In this case they would have used “relative dating” where they would figure out which dinosaur the footprints belonged to. Based on the ages that have been calculated for that specific dinosaur from other sites around the world, we can then make a pretty good guess of how old the prints are. Obviously this will only work if it’s an organism that we previously know about and have good age control on it’s position in the fossil record.
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